go.mod: bump client-go and api machinerie

I had to run `make generate`.
Some API functions got additional parameters `Options` and `Context`.
I used empty options and `context.TODO()` for now.

Signed-off-by: leonnicolas <leonloechner@gmx.de>

vendor/golang.org/x/tools/go/ast/astutil/imports.go

@@ -275,9 +275,10 @@ func DeleteNamedImport(fset *token.FileSet, f *ast.File, name, path string) (del
 
 				// We deleted an entry but now there may be
 				// a blank line-sized hole where the import was.
-				if line-lastLine > 1 {
+				if line-lastLine > 1 || !gen.Rparen.IsValid() {
 					// There was a blank line immediately preceding the deleted import,
-					// so there's no need to close the hole.
+					// so there's no need to close the hole. The right parenthesis is
+					// invalid after AddImport to an import statement without parenthesis.
 					// Do nothing.
 				} else if line != fset.File(gen.Rparen).LineCount() {
 					// There was no blank line. Close the hole.

vendor/golang.org/x/tools/go/ast/astutil/util.go

@@ -1,3 +1,7 @@
+// Copyright 2015 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
 package astutil
 
 import "go/ast"

vendor/golang.org/x/tools/go/gcexportdata/gcexportdata.go

@@ -100,7 +100,7 @@ func Read(in io.Reader, fset *token.FileSet, imports map[string]*types.Package,
 // Write writes encoded type information for the specified package to out.
 // The FileSet provides file position information for named objects.
 func Write(out io.Writer, fset *token.FileSet, pkg *types.Package) error {
-	b, err := gcimporter.BExportData(fset, pkg)
+	b, err := gcimporter.IExportData(fset, pkg)
 	if err != nil {
 		return err
 	}

vendor/golang.org/x/tools/go/internal/gcimporter/bimport.go

@@ -332,7 +332,7 @@ func (p *importer) pos() token.Pos {
 	p.prevFile = file
 	p.prevLine = line
 
-	return p.fake.pos(file, line)
+	return p.fake.pos(file, line, 0)
 }
 
 // Synthesize a token.Pos
@@ -341,7 +341,9 @@ type fakeFileSet struct {
 	files map[string]*token.File
 }
 
-func (s *fakeFileSet) pos(file string, line int) token.Pos {
+func (s *fakeFileSet) pos(file string, line, column int) token.Pos {
+	// TODO(mdempsky): Make use of column.
+
 	// Since we don't know the set of needed file positions, we
 	// reserve maxlines positions per file.
 	const maxlines = 64 * 1024
@@ -976,10 +978,11 @@ const (
 	aliasTag
 )
 
+var predeclOnce sync.Once
 var predecl []types.Type // initialized lazily
 
 func predeclared() []types.Type {
-	if predecl == nil {
+	predeclOnce.Do(func() {
 		// initialize lazily to be sure that all
 		// elements have been initialized before
 		predecl = []types.Type{ // basic types
@@ -1026,7 +1029,7 @@ func predeclared() []types.Type {
 			// used internally by gc; never used by this package or in .a files
 			anyType{},
 		}
-	}
+	})
 	return predecl
 }
 

vendor/golang.org/x/tools/go/internal/gcimporter/gcimporter.go

@@ -344,7 +344,7 @@ func (p *parser) expectKeyword(keyword string) {
 
 // PackageId = string_lit .
 //
-func (p *parser) parsePackageId() string {
+func (p *parser) parsePackageID() string {
 	id, err := strconv.Unquote(p.expect(scanner.String))
 	if err != nil {
 		p.error(err)
@@ -384,7 +384,7 @@ func (p *parser) parseDotIdent() string {
 //
 func (p *parser) parseQualifiedName() (id, name string) {
 	p.expect('@')
-	id = p.parsePackageId()
+	id = p.parsePackageID()
 	p.expect('.')
 	// Per rev f280b8a485fd (10/2/2013), qualified names may be used for anonymous fields.
 	if p.tok == '?' {
@@ -491,7 +491,7 @@ func (p *parser) parseMapType(parent *types.Package) types.Type {
 //
 // For unqualified and anonymous names, the returned package is the parent
 // package unless parent == nil, in which case the returned package is the
-// package being imported. (The parent package is not nil if the the name
+// package being imported. (The parent package is not nil if the name
 // is an unqualified struct field or interface method name belonging to a
 // type declared in another package.)
 //
@@ -696,7 +696,7 @@ func (p *parser) parseInterfaceType(parent *types.Package) types.Type {
 
 	// Complete requires the type's embedded interfaces to be fully defined,
 	// but we do not define any
-	return types.NewInterface(methods, nil).Complete()
+	return newInterface(methods, nil).Complete()
 }
 
 // ChanType = ( "chan" [ "<-" ] | "<-" "chan" ) Type .
@@ -785,7 +785,7 @@ func (p *parser) parseType(parent *types.Package) types.Type {
 func (p *parser) parseImportDecl() {
 	p.expectKeyword("import")
 	name := p.parsePackageName()
-	p.getPkg(p.parsePackageId(), name)
+	p.getPkg(p.parsePackageID(), name)
 }
 
 // int_lit = [ "+" | "-" ] { "0" ... "9" } .

vendor/golang.org/x/tools/go/internal/gcimporter/iexport.go

@@ -6,8 +6,6 @@
 // This file was derived from $GOROOT/src/cmd/compile/internal/gc/iexport.go;
 // see that file for specification of the format.
 
-// +build go1.11
-
 package gcimporter
 
 import (
@@ -28,7 +26,10 @@ import (
 const iexportVersion = 0
 
 // IExportData returns the binary export data for pkg.
+//
 // If no file set is provided, position info will be missing.
+// The package path of the top-level package will not be recorded,
+// so that calls to IImportData can override with a provided package path.
 func IExportData(fset *token.FileSet, pkg *types.Package) (b []byte, err error) {
 	defer func() {
 		if e := recover(); e != nil {
@@ -48,6 +49,7 @@ func IExportData(fset *token.FileSet, pkg *types.Package) (b []byte, err error)
 		stringIndex: map[string]uint64{},
 		declIndex:   map[types.Object]uint64{},
 		typIndex:    map[types.Type]uint64{},
+		localpkg:    pkg,
 	}
 
 	for i, pt := range predeclared() {
@@ -73,7 +75,7 @@ func IExportData(fset *token.FileSet, pkg *types.Package) (b []byte, err error)
 	// Append indices to data0 section.
 	dataLen := uint64(p.data0.Len())
 	w := p.newWriter()
-	w.writeIndex(p.declIndex, pkg)
+	w.writeIndex(p.declIndex)
 	w.flush()
 
 	// Assemble header.
@@ -95,14 +97,14 @@ func IExportData(fset *token.FileSet, pkg *types.Package) (b []byte, err error)
 // we're writing out the main index, which is also read by
 // non-compiler tools and includes a complete package description
 // (i.e., name and height).
-func (w *exportWriter) writeIndex(index map[types.Object]uint64, localpkg *types.Package) {
+func (w *exportWriter) writeIndex(index map[types.Object]uint64) {
 	// Build a map from packages to objects from that package.
 	pkgObjs := map[*types.Package][]types.Object{}
 
 	// For the main index, make sure to include every package that
 	// we reference, even if we're not exporting (or reexporting)
 	// any symbols from it.
-	pkgObjs[localpkg] = nil
+	pkgObjs[w.p.localpkg] = nil
 	for pkg := range w.p.allPkgs {
 		pkgObjs[pkg] = nil
 	}
@@ -121,12 +123,12 @@ func (w *exportWriter) writeIndex(index map[types.Object]uint64, localpkg *types
 	}
 
 	sort.Slice(pkgs, func(i, j int) bool {
-		return pkgs[i].Path() < pkgs[j].Path()
+		return w.exportPath(pkgs[i]) < w.exportPath(pkgs[j])
 	})
 
 	w.uint64(uint64(len(pkgs)))
 	for _, pkg := range pkgs {
-		w.string(pkg.Path())
+		w.string(w.exportPath(pkg))
 		w.string(pkg.Name())
 		w.uint64(uint64(0)) // package height is not needed for go/types
 
@@ -143,6 +145,8 @@ type iexporter struct {
 	fset *token.FileSet
 	out  *bytes.Buffer
 
+	localpkg *types.Package
+
 	// allPkgs tracks all packages that have been referenced by
 	// the export data, so we can ensure to include them in the
 	// main index.
@@ -195,6 +199,13 @@ type exportWriter struct {
 	prevLine int64
 }
 
+func (w *exportWriter) exportPath(pkg *types.Package) string {
+	if pkg == w.p.localpkg {
+		return ""
+	}
+	return pkg.Path()
+}
+
 func (p *iexporter) doDecl(obj types.Object) {
 	w := p.newWriter()
 	w.setPkg(obj.Pkg(), false)
@@ -267,6 +278,11 @@ func (w *exportWriter) tag(tag byte) {
 }
 
 func (w *exportWriter) pos(pos token.Pos) {
+	if w.p.fset == nil {
+		w.int64(0)
+		return
+	}
+
 	p := w.p.fset.Position(pos)
 	file := p.Filename
 	line := int64(p.Line)
@@ -299,7 +315,7 @@ func (w *exportWriter) pkg(pkg *types.Package) {
 	// Ensure any referenced packages are declared in the main index.
 	w.p.allPkgs[pkg] = true
 
-	w.string(pkg.Path())
+	w.string(w.exportPath(pkg))
 }
 
 func (w *exportWriter) qualifiedIdent(obj types.Object) {
@@ -394,7 +410,7 @@ func (w *exportWriter) doTyp(t types.Type, pkg *types.Package) {
 			w.pos(f.Pos())
 			w.string(f.Name())
 			w.typ(f.Type(), pkg)
-			w.bool(f.Embedded())
+			w.bool(f.Anonymous())
 			w.string(t.Tag(i)) // note (or tag)
 		}
 

vendor/golang.org/x/tools/go/internal/gcimporter/iimport.go

@@ -63,8 +63,8 @@ const (
 // If the export data version is not recognized or the format is otherwise
 // compromised, an error is returned.
 func IImportData(fset *token.FileSet, imports map[string]*types.Package, data []byte, path string) (_ int, pkg *types.Package, err error) {
-	const currentVersion = 0
-	version := -1
+	const currentVersion = 1
+	version := int64(-1)
 	defer func() {
 		if e := recover(); e != nil {
 			if version > currentVersion {
@@ -77,9 +77,9 @@ func IImportData(fset *token.FileSet, imports map[string]*types.Package, data []
 
 	r := &intReader{bytes.NewReader(data), path}
 
-	version = int(r.uint64())
+	version = int64(r.uint64())
 	switch version {
-	case currentVersion:
+	case currentVersion, 0:
 	default:
 		errorf("unknown iexport format version %d", version)
 	}
@@ -93,7 +93,8 @@ func IImportData(fset *token.FileSet, imports map[string]*types.Package, data []
 	r.Seek(sLen+dLen, io.SeekCurrent)
 
 	p := iimporter{
-		ipath: path,
+		ipath:   path,
+		version: int(version),
 
 		stringData:  stringData,
 		stringCache: make(map[uint64]string),
@@ -142,20 +143,18 @@ func IImportData(fset *token.FileSet, imports map[string]*types.Package, data []
 		p.pkgIndex[pkg] = nameIndex
 		pkgList[i] = pkg
 	}
-	var localpkg *types.Package
-	for _, pkg := range pkgList {
-		if pkg.Path() == path {
-			localpkg = pkg
-		}
+	if len(pkgList) == 0 {
+		errorf("no packages found for %s", path)
+		panic("unreachable")
 	}
-
-	names := make([]string, 0, len(p.pkgIndex[localpkg]))
-	for name := range p.pkgIndex[localpkg] {
+	p.ipkg = pkgList[0]
+	names := make([]string, 0, len(p.pkgIndex[p.ipkg]))
+	for name := range p.pkgIndex[p.ipkg] {
 		names = append(names, name)
 	}
 	sort.Strings(names)
 	for _, name := range names {
-		p.doDecl(localpkg, name)
+		p.doDecl(p.ipkg, name)
 	}
 
 	for _, typ := range p.interfaceList {
@@ -165,17 +164,19 @@ func IImportData(fset *token.FileSet, imports map[string]*types.Package, data []
 	// record all referenced packages as imports
 	list := append(([]*types.Package)(nil), pkgList[1:]...)
 	sort.Sort(byPath(list))
-	localpkg.SetImports(list)
+	p.ipkg.SetImports(list)
 
 	// package was imported completely and without errors
-	localpkg.MarkComplete()
+	p.ipkg.MarkComplete()
 
 	consumed, _ := r.Seek(0, io.SeekCurrent)
-	return int(consumed), localpkg, nil
+	return int(consumed), p.ipkg, nil
 }
 
 type iimporter struct {
-	ipath string
+	ipath   string
+	ipkg    *types.Package
+	version int
 
 	stringData  []byte
 	stringCache map[uint64]string
@@ -226,6 +227,9 @@ func (p *iimporter) pkgAt(off uint64) *types.Package {
 		return pkg
 	}
 	path := p.stringAt(off)
+	if path == p.ipath {
+		return p.ipkg
+	}
 	errorf("missing package %q in %q", path, p.ipath)
 	return nil
 }
@@ -255,6 +259,7 @@ type importReader struct {
 	currPkg    *types.Package
 	prevFile   string
 	prevLine   int64
+	prevColumn int64
 }
 
 func (r *importReader) obj(name string) {
@@ -448,6 +453,19 @@ func (r *importReader) qualifiedIdent() (*types.Package, string) {
 }
 
 func (r *importReader) pos() token.Pos {
+	if r.p.version >= 1 {
+		r.posv1()
+	} else {
+		r.posv0()
+	}
+
+	if r.prevFile == "" && r.prevLine == 0 && r.prevColumn == 0 {
+		return token.NoPos
+	}
+	return r.p.fake.pos(r.prevFile, int(r.prevLine), int(r.prevColumn))
+}
+
+func (r *importReader) posv0() {
 	delta := r.int64()
 	if delta != deltaNewFile {
 		r.prevLine += delta
@@ -457,12 +475,18 @@ func (r *importReader) pos() token.Pos {
 		r.prevFile = r.string()
 		r.prevLine = l
 	}
+}
 
-	if r.prevFile == "" && r.prevLine == 0 {
-		return token.NoPos
+func (r *importReader) posv1() {
+	delta := r.int64()
+	r.prevColumn += delta >> 1
+	if delta&1 != 0 {
+		delta = r.int64()
+		r.prevLine += delta >> 1
+		if delta&1 != 0 {
+			r.prevFile = r.string()
+		}
 	}
-
-	return r.p.fake.pos(r.prevFile, int(r.prevLine))
 }
 
 func (r *importReader) typ() types.Type {

vendor/golang.org/x/tools/go/internal/packagesdriver/sizes.go

@@ -1,160 +0,0 @@
-// Copyright 2018 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-// Package packagesdriver fetches type sizes for go/packages and go/analysis.
-package packagesdriver
-
-import (
-	"bytes"
-	"context"
-	"encoding/json"
-	"fmt"
-	"go/types"
-	"log"
-	"os"
-	"os/exec"
-	"strings"
-	"time"
-)
-
-var debug = false
-
-// GetSizes returns the sizes used by the underlying driver with the given parameters.
-func GetSizes(ctx context.Context, buildFlags, env []string, dir string, usesExportData bool) (types.Sizes, error) {
-	// TODO(matloob): Clean this up. This code is mostly a copy of packages.findExternalDriver.
-	const toolPrefix = "GOPACKAGESDRIVER="
-	tool := ""
-	for _, env := range env {
-		if val := strings.TrimPrefix(env, toolPrefix); val != env {
-			tool = val
-		}
-	}
-
-	if tool == "" {
-		var err error
-		tool, err = exec.LookPath("gopackagesdriver")
-		if err != nil {
-			// We did not find the driver, so use "go list".
-			tool = "off"
-		}
-	}
-
-	if tool == "off" {
-		return GetSizesGolist(ctx, buildFlags, env, dir, usesExportData)
-	}
-
-	req, err := json.Marshal(struct {
-		Command    string   `json:"command"`
-		Env        []string `json:"env"`
-		BuildFlags []string `json:"build_flags"`
-	}{
-		Command:    "sizes",
-		Env:        env,
-		BuildFlags: buildFlags,
-	})
-	if err != nil {
-		return nil, fmt.Errorf("failed to encode message to driver tool: %v", err)
-	}
-
-	buf := new(bytes.Buffer)
-	cmd := exec.CommandContext(ctx, tool)
-	cmd.Dir = dir
-	cmd.Env = env
-	cmd.Stdin = bytes.NewReader(req)
-	cmd.Stdout = buf
-	cmd.Stderr = new(bytes.Buffer)
-	if err := cmd.Run(); err != nil {
-		return nil, fmt.Errorf("%v: %v: %s", tool, err, cmd.Stderr)
-	}
-	var response struct {
-		// Sizes, if not nil, is the types.Sizes to use when type checking.
-		Sizes *types.StdSizes
-	}
-	if err := json.Unmarshal(buf.Bytes(), &response); err != nil {
-		return nil, err
-	}
-	return response.Sizes, nil
-}
-
-func GetSizesGolist(ctx context.Context, buildFlags, env []string, dir string, usesExportData bool) (types.Sizes, error) {
-	args := []string{"list", "-f", "{{context.GOARCH}} {{context.Compiler}}"}
-	args = append(args, buildFlags...)
-	args = append(args, "--", "unsafe")
-	stdout, err := InvokeGo(ctx, env, dir, usesExportData, args...)
-	if err != nil {
-		return nil, err
-	}
-	fields := strings.Fields(stdout.String())
-	if len(fields) < 2 {
-		return nil, fmt.Errorf("could not determine GOARCH and Go compiler")
-	}
-	goarch := fields[0]
-	compiler := fields[1]
-	return types.SizesFor(compiler, goarch), nil
-}
-
-// InvokeGo returns the stdout of a go command invocation.
-func InvokeGo(ctx context.Context, env []string, dir string, usesExportData bool, args ...string) (*bytes.Buffer, error) {
-	if debug {
-		defer func(start time.Time) { log.Printf("%s for %v", time.Since(start), cmdDebugStr(env, args...)) }(time.Now())
-	}
-	stdout := new(bytes.Buffer)
-	stderr := new(bytes.Buffer)
-	cmd := exec.CommandContext(ctx, "go", args...)
-	// On darwin the cwd gets resolved to the real path, which breaks anything that
-	// expects the working directory to keep the original path, including the
-	// go command when dealing with modules.
-	// The Go stdlib has a special feature where if the cwd and the PWD are the
-	// same node then it trusts the PWD, so by setting it in the env for the child
-	// process we fix up all the paths returned by the go command.
-	cmd.Env = append(append([]string{}, env...), "PWD="+dir)
-	cmd.Dir = dir
-	cmd.Stdout = stdout
-	cmd.Stderr = stderr
-	if err := cmd.Run(); err != nil {
-		exitErr, ok := err.(*exec.ExitError)
-		if !ok {
-			// Catastrophic error:
-			// - executable not found
-			// - context cancellation
-			return nil, fmt.Errorf("couldn't exec 'go %v': %s %T", args, err, err)
-		}
-
-		// Export mode entails a build.
-		// If that build fails, errors appear on stderr
-		// (despite the -e flag) and the Export field is blank.
-		// Do not fail in that case.
-		if !usesExportData {
-			return nil, fmt.Errorf("go %v: %s: %s", args, exitErr, stderr)
-		}
-	}
-
-	// As of writing, go list -export prints some non-fatal compilation
-	// errors to stderr, even with -e set. We would prefer that it put
-	// them in the Package.Error JSON (see https://golang.org/issue/26319).
-	// In the meantime, there's nowhere good to put them, but they can
-	// be useful for debugging. Print them if $GOPACKAGESPRINTGOLISTERRORS
-	// is set.
-	if len(stderr.Bytes()) != 0 && os.Getenv("GOPACKAGESPRINTGOLISTERRORS") != "" {
-		fmt.Fprintf(os.Stderr, "%s stderr: <<%s>>\n", cmdDebugStr(env, args...), stderr)
-	}
-
-	// debugging
-	if false {
-		fmt.Fprintf(os.Stderr, "%s stdout: <<%s>>\n", cmdDebugStr(env, args...), stdout)
-	}
-
-	return stdout, nil
-}
-
-func cmdDebugStr(envlist []string, args ...string) string {
-	env := make(map[string]string)
-	for _, kv := range envlist {
-		split := strings.Split(kv, "=")
-		k, v := split[0], split[1]
-		env[k] = v
-	}
-
-	return fmt.Sprintf("GOROOT=%v GOPATH=%v GO111MODULE=%v PWD=%v go %v", env["GOROOT"], env["GOPATH"], env["GO111MODULE"], env["PWD"], args)
-}

vendor/golang.org/x/tools/go/packages/doc.go

@@ -1,222 +0,0 @@
-// Copyright 2018 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-/*
-Package packages loads Go packages for inspection and analysis.
-
-The Load function takes as input a list of patterns and return a list of Package
-structs describing individual packages matched by those patterns.
-The LoadMode controls the amount of detail in the loaded packages.
-
-Load passes most patterns directly to the underlying build tool,
-but all patterns with the prefix "query=", where query is a
-non-empty string of letters from [a-z], are reserved and may be
-interpreted as query operators.
-
-Two query operators are currently supported: "file" and "pattern".
-
-The query "file=path/to/file.go" matches the package or packages enclosing
-the Go source file path/to/file.go.  For example "file=~/go/src/fmt/print.go"
-might return the packages "fmt" and "fmt [fmt.test]".
-
-The query "pattern=string" causes "string" to be passed directly to
-the underlying build tool. In most cases this is unnecessary,
-but an application can use Load("pattern=" + x) as an escaping mechanism
-to ensure that x is not interpreted as a query operator if it contains '='.
-
-All other query operators are reserved for future use and currently
-cause Load to report an error.
-
-The Package struct provides basic information about the package, including
-
-  - ID, a unique identifier for the package in the returned set;
-  - GoFiles, the names of the package's Go source files;
-  - Imports, a map from source import strings to the Packages they name;
-  - Types, the type information for the package's exported symbols;
-  - Syntax, the parsed syntax trees for the package's source code; and
-  - TypeInfo, the result of a complete type-check of the package syntax trees.
-
-(See the documentation for type Package for the complete list of fields
-and more detailed descriptions.)
-
-For example,
-
-	Load(nil, "bytes", "unicode...")
-
-returns four Package structs describing the standard library packages
-bytes, unicode, unicode/utf16, and unicode/utf8. Note that one pattern
-can match multiple packages and that a package might be matched by
-multiple patterns: in general it is not possible to determine which
-packages correspond to which patterns.
-
-Note that the list returned by Load contains only the packages matched
-by the patterns. Their dependencies can be found by walking the import
-graph using the Imports fields.
-
-The Load function can be configured by passing a pointer to a Config as
-the first argument. A nil Config is equivalent to the zero Config, which
-causes Load to run in LoadFiles mode, collecting minimal information.
-See the documentation for type Config for details.
-
-As noted earlier, the Config.Mode controls the amount of detail
-reported about the loaded packages, with each mode returning all the data of the
-previous mode with some extra added. See the documentation for type LoadMode
-for details.
-
-Most tools should pass their command-line arguments (after any flags)
-uninterpreted to the loader, so that the loader can interpret them
-according to the conventions of the underlying build system.
-See the Example function for typical usage.
-
-*/
-package packages // import "golang.org/x/tools/go/packages"
-
-/*
-
-Motivation and design considerations
-
-The new package's design solves problems addressed by two existing
-packages: go/build, which locates and describes packages, and
-golang.org/x/tools/go/loader, which loads, parses and type-checks them.
-The go/build.Package structure encodes too much of the 'go build' way
-of organizing projects, leaving us in need of a data type that describes a
-package of Go source code independent of the underlying build system.
-We wanted something that works equally well with go build and vgo, and
-also other build systems such as Bazel and Blaze, making it possible to
-construct analysis tools that work in all these environments.
-Tools such as errcheck and staticcheck were essentially unavailable to
-the Go community at Google, and some of Google's internal tools for Go
-are unavailable externally.
-This new package provides a uniform way to obtain package metadata by
-querying each of these build systems, optionally supporting their
-preferred command-line notations for packages, so that tools integrate
-neatly with users' build environments. The Metadata query function
-executes an external query tool appropriate to the current workspace.
-
-Loading packages always returns the complete import graph "all the way down",
-even if all you want is information about a single package, because the query
-mechanisms of all the build systems we currently support ({go,vgo} list, and
-blaze/bazel aspect-based query) cannot provide detailed information
-about one package without visiting all its dependencies too, so there is
-no additional asymptotic cost to providing transitive information.
-(This property might not be true of a hypothetical 5th build system.)
-
-In calls to TypeCheck, all initial packages, and any package that
-transitively depends on one of them, must be loaded from source.
-Consider A->B->C->D->E: if A,C are initial, A,B,C must be loaded from
-source; D may be loaded from export data, and E may not be loaded at all
-(though it's possible that D's export data mentions it, so a
-types.Package may be created for it and exposed.)
-
-The old loader had a feature to suppress type-checking of function
-bodies on a per-package basis, primarily intended to reduce the work of
-obtaining type information for imported packages. Now that imports are
-satisfied by export data, the optimization no longer seems necessary.
-
-Despite some early attempts, the old loader did not exploit export data,
-instead always using the equivalent of WholeProgram mode. This was due
-to the complexity of mixing source and export data packages (now
-resolved by the upward traversal mentioned above), and because export data
-files were nearly always missing or stale. Now that 'go build' supports
-caching, all the underlying build systems can guarantee to produce
-export data in a reasonable (amortized) time.
-
-Test "main" packages synthesized by the build system are now reported as
-first-class packages, avoiding the need for clients (such as go/ssa) to
-reinvent this generation logic.
-
-One way in which go/packages is simpler than the old loader is in its
-treatment of in-package tests. In-package tests are packages that
-consist of all the files of the library under test, plus the test files.
-The old loader constructed in-package tests by a two-phase process of
-mutation called "augmentation": first it would construct and type check
-all the ordinary library packages and type-check the packages that
-depend on them; then it would add more (test) files to the package and
-type-check again. This two-phase approach had four major problems:
-1) in processing the tests, the loader modified the library package,
-   leaving no way for a client application to see both the test
-   package and the library package; one would mutate into the other.
-2) because test files can declare additional methods on types defined in
-   the library portion of the package, the dispatch of method calls in
-   the library portion was affected by the presence of the test files.
-   This should have been a clue that the packages were logically
-   different.
-3) this model of "augmentation" assumed at most one in-package test
-   per library package, which is true of projects using 'go build',
-   but not other build systems.
-4) because of the two-phase nature of test processing, all packages that
-   import the library package had to be processed before augmentation,
-   forcing a "one-shot" API and preventing the client from calling Load
-   in several times in sequence as is now possible in WholeProgram mode.
-   (TypeCheck mode has a similar one-shot restriction for a different reason.)
-
-Early drafts of this package supported "multi-shot" operation.
-Although it allowed clients to make a sequence of calls (or concurrent
-calls) to Load, building up the graph of Packages incrementally,
-it was of marginal value: it complicated the API
-(since it allowed some options to vary across calls but not others),
-it complicated the implementation,
-it cannot be made to work in Types mode, as explained above,
-and it was less efficient than making one combined call (when this is possible).
-Among the clients we have inspected, none made multiple calls to load
-but could not be easily and satisfactorily modified to make only a single call.
-However, applications changes may be required.
-For example, the ssadump command loads the user-specified packages
-and in addition the runtime package.  It is tempting to simply append
-"runtime" to the user-provided list, but that does not work if the user
-specified an ad-hoc package such as [a.go b.go].
-Instead, ssadump no longer requests the runtime package,
-but seeks it among the dependencies of the user-specified packages,
-and emits an error if it is not found.
-
-Overlays: The Overlay field in the Config allows providing alternate contents
-for Go source files, by providing a mapping from file path to contents.
-go/packages will pull in new imports added in overlay files when go/packages
-is run in LoadImports mode or greater.
-Overlay support for the go list driver isn't complete yet: if the file doesn't
-exist on disk, it will only be recognized in an overlay if it is a non-test file
-and the package would be reported even without the overlay.
-
-Questions & Tasks
-
-- Add GOARCH/GOOS?
-  They are not portable concepts, but could be made portable.
-  Our goal has been to allow users to express themselves using the conventions
-  of the underlying build system: if the build system honors GOARCH
-  during a build and during a metadata query, then so should
-  applications built atop that query mechanism.
-  Conversely, if the target architecture of the build is determined by
-  command-line flags, the application can pass the relevant
-  flags through to the build system using a command such as:
-    myapp -query_flag="--cpu=amd64" -query_flag="--os=darwin"
-  However, this approach is low-level, unwieldy, and non-portable.
-  GOOS and GOARCH seem important enough to warrant a dedicated option.
-
-- How should we handle partial failures such as a mixture of good and
-  malformed patterns, existing and non-existent packages, successful and
-  failed builds, import failures, import cycles, and so on, in a call to
-  Load?
-
-- Support bazel, blaze, and go1.10 list, not just go1.11 list.
-
-- Handle (and test) various partial success cases, e.g.
-  a mixture of good packages and:
-  invalid patterns
-  nonexistent packages
-  empty packages
-  packages with malformed package or import declarations
-  unreadable files
-  import cycles
-  other parse errors
-  type errors
-  Make sure we record errors at the correct place in the graph.
-
-- Missing packages among initial arguments are not reported.
-  Return bogus packages for them, like golist does.
-
-- "undeclared name" errors (for example) are reported out of source file
-  order. I suspect this is due to the breadth-first resolution now used
-  by go/types. Is that a bug? Discuss with gri.
-
-*/

vendor/golang.org/x/tools/go/packages/external.go

@@ -1,79 +0,0 @@
-// Copyright 2018 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-// This file enables an external tool to intercept package requests.
-// If the tool is present then its results are used in preference to
-// the go list command.
-
-package packages
-
-import (
-	"bytes"
-	"encoding/json"
-	"fmt"
-	"os/exec"
-	"strings"
-)
-
-// Driver
-type driverRequest struct {
-	Command    string            `json "command"`
-	Mode       LoadMode          `json:"mode"`
-	Env        []string          `json:"env"`
-	BuildFlags []string          `json:"build_flags"`
-	Tests      bool              `json:"tests"`
-	Overlay    map[string][]byte `json:"overlay"`
-}
-
-// findExternalDriver returns the file path of a tool that supplies
-// the build system package structure, or "" if not found."
-// If GOPACKAGESDRIVER is set in the environment findExternalTool returns its
-// value, otherwise it searches for a binary named gopackagesdriver on the PATH.
-func findExternalDriver(cfg *Config) driver {
-	const toolPrefix = "GOPACKAGESDRIVER="
-	tool := ""
-	for _, env := range cfg.Env {
-		if val := strings.TrimPrefix(env, toolPrefix); val != env {
-			tool = val
-		}
-	}
-	if tool != "" && tool == "off" {
-		return nil
-	}
-	if tool == "" {
-		var err error
-		tool, err = exec.LookPath("gopackagesdriver")
-		if err != nil {
-			return nil
-		}
-	}
-	return func(cfg *Config, words ...string) (*driverResponse, error) {
-		req, err := json.Marshal(driverRequest{
-			Mode:       cfg.Mode,
-			Env:        cfg.Env,
-			BuildFlags: cfg.BuildFlags,
-			Tests:      cfg.Tests,
-			Overlay:    cfg.Overlay,
-		})
-		if err != nil {
-			return nil, fmt.Errorf("failed to encode message to driver tool: %v", err)
-		}
-
-		buf := new(bytes.Buffer)
-		cmd := exec.CommandContext(cfg.Context, tool, words...)
-		cmd.Dir = cfg.Dir
-		cmd.Env = cfg.Env
-		cmd.Stdin = bytes.NewReader(req)
-		cmd.Stdout = buf
-		cmd.Stderr = new(bytes.Buffer)
-		if err := cmd.Run(); err != nil {
-			return nil, fmt.Errorf("%v: %v: %s", tool, err, cmd.Stderr)
-		}
-		var response driverResponse
-		if err := json.Unmarshal(buf.Bytes(), &response); err != nil {
-			return nil, err
-		}
-		return &response, nil
-	}
-}

vendor/golang.org/x/tools/go/packages/golist.go

@@ -1,821 +0,0 @@
-// Copyright 2018 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-package packages
-
-import (
-	"bytes"
-	"encoding/json"
-	"fmt"
-	"go/types"
-	"io/ioutil"
-	"log"
-	"os"
-	"os/exec"
-	"path/filepath"
-	"reflect"
-	"regexp"
-	"strconv"
-	"strings"
-	"sync"
-	"time"
-
-	"golang.org/x/tools/go/internal/packagesdriver"
-	"golang.org/x/tools/internal/gopathwalk"
-	"golang.org/x/tools/internal/semver"
-)
-
-// debug controls verbose logging.
-var debug, _ = strconv.ParseBool(os.Getenv("GOPACKAGESDEBUG"))
-
-// A goTooOldError reports that the go command
-// found by exec.LookPath is too old to use the new go list behavior.
-type goTooOldError struct {
-	error
-}
-
-// responseDeduper wraps a driverResponse, deduplicating its contents.
-type responseDeduper struct {
-	seenRoots    map[string]bool
-	seenPackages map[string]*Package
-	dr           *driverResponse
-}
-
-// init fills in r with a driverResponse.
-func (r *responseDeduper) init(dr *driverResponse) {
-	r.dr = dr
-	r.seenRoots = map[string]bool{}
-	r.seenPackages = map[string]*Package{}
-	for _, pkg := range dr.Packages {
-		r.seenPackages[pkg.ID] = pkg
-	}
-	for _, root := range dr.Roots {
-		r.seenRoots[root] = true
-	}
-}
-
-func (r *responseDeduper) addPackage(p *Package) {
-	if r.seenPackages[p.ID] != nil {
-		return
-	}
-	r.seenPackages[p.ID] = p
-	r.dr.Packages = append(r.dr.Packages, p)
-}
-
-func (r *responseDeduper) addRoot(id string) {
-	if r.seenRoots[id] {
-		return
-	}
-	r.seenRoots[id] = true
-	r.dr.Roots = append(r.dr.Roots, id)
-}
-
-// goListDriver uses the go list command to interpret the patterns and produce
-// the build system package structure.
-// See driver for more details.
-func goListDriver(cfg *Config, patterns ...string) (*driverResponse, error) {
-	var sizes types.Sizes
-	var sizeserr error
-	var sizeswg sync.WaitGroup
-	if cfg.Mode&NeedTypesSizes != 0 {
-		sizeswg.Add(1)
-		go func() {
-			sizes, sizeserr = getSizes(cfg)
-			sizeswg.Done()
-		}()
-	}
-
-	// Determine files requested in contains patterns
-	var containFiles []string
-	var packagesNamed []string
-	restPatterns := make([]string, 0, len(patterns))
-	// Extract file= and other [querytype]= patterns. Report an error if querytype
-	// doesn't exist.
-extractQueries:
-	for _, pattern := range patterns {
-		eqidx := strings.Index(pattern, "=")
-		if eqidx < 0 {
-			restPatterns = append(restPatterns, pattern)
-		} else {
-			query, value := pattern[:eqidx], pattern[eqidx+len("="):]
-			switch query {
-			case "file":
-				containFiles = append(containFiles, value)
-			case "pattern":
-				restPatterns = append(restPatterns, value)
-			case "iamashamedtousethedisabledqueryname":
-				packagesNamed = append(packagesNamed, value)
-			case "": // not a reserved query
-				restPatterns = append(restPatterns, pattern)
-			default:
-				for _, rune := range query {
-					if rune < 'a' || rune > 'z' { // not a reserved query
-						restPatterns = append(restPatterns, pattern)
-						continue extractQueries
-					}
-				}
-				// Reject all other patterns containing "="
-				return nil, fmt.Errorf("invalid query type %q in query pattern %q", query, pattern)
-			}
-		}
-	}
-
-	response := &responseDeduper{}
-	var err error
-
-	// See if we have any patterns to pass through to go list. Zero initial
-	// patterns also requires a go list call, since it's the equivalent of
-	// ".".
-	if len(restPatterns) > 0 || len(patterns) == 0 {
-		dr, err := golistDriverCurrent(cfg, restPatterns...)
-		if err != nil {
-			return nil, err
-		}
-		response.init(dr)
-	} else {
-		response.init(&driverResponse{})
-	}
-
-	sizeswg.Wait()
-	if sizeserr != nil {
-		return nil, sizeserr
-	}
-	// types.SizesFor always returns nil or a *types.StdSizes
-	response.dr.Sizes, _ = sizes.(*types.StdSizes)
-
-	var containsCandidates []string
-
-	if len(containFiles) != 0 {
-		if err := runContainsQueries(cfg, golistDriverCurrent, response, containFiles); err != nil {
-			return nil, err
-		}
-	}
-
-	if len(packagesNamed) != 0 {
-		if err := runNamedQueries(cfg, golistDriverCurrent, response, packagesNamed); err != nil {
-			return nil, err
-		}
-	}
-
-	modifiedPkgs, needPkgs, err := processGolistOverlay(cfg, response.dr)
-	if err != nil {
-		return nil, err
-	}
-	if len(containFiles) > 0 {
-		containsCandidates = append(containsCandidates, modifiedPkgs...)
-		containsCandidates = append(containsCandidates, needPkgs...)
-	}
-
-	if len(needPkgs) > 0 {
-		addNeededOverlayPackages(cfg, golistDriverCurrent, response, needPkgs)
-		if err != nil {
-			return nil, err
-		}
-	}
-	// Check candidate packages for containFiles.
-	if len(containFiles) > 0 {
-		for _, id := range containsCandidates {
-			pkg := response.seenPackages[id]
-			for _, f := range containFiles {
-				for _, g := range pkg.GoFiles {
-					if sameFile(f, g) {
-						response.addRoot(id)
-					}
-				}
-			}
-		}
-	}
-
-	return response.dr, nil
-}
-
-func addNeededOverlayPackages(cfg *Config, driver driver, response *responseDeduper, pkgs []string) error {
-	dr, err := driver(cfg, pkgs...)
-	if err != nil {
-		return err
-	}
-	for _, pkg := range dr.Packages {
-		response.addPackage(pkg)
-	}
-	return nil
-}
-
-func runContainsQueries(cfg *Config, driver driver, response *responseDeduper, queries []string) error {
-	for _, query := range queries {
-		// TODO(matloob): Do only one query per directory.
-		fdir := filepath.Dir(query)
-		// Pass absolute path of directory to go list so that it knows to treat it as a directory,
-		// not a package path.
-		pattern, err := filepath.Abs(fdir)
-		if err != nil {
-			return fmt.Errorf("could not determine absolute path of file= query path %q: %v", query, err)
-		}
-		dirResponse, err := driver(cfg, pattern)
-		if err != nil {
-			return err
-		}
-		isRoot := make(map[string]bool, len(dirResponse.Roots))
-		for _, root := range dirResponse.Roots {
-			isRoot[root] = true
-		}
-		for _, pkg := range dirResponse.Packages {
-			// Add any new packages to the main set
-			// We don't bother to filter packages that will be dropped by the changes of roots,
-			// that will happen anyway during graph construction outside this function.
-			// Over-reporting packages is not a problem.
-			response.addPackage(pkg)
-			// if the package was not a root one, it cannot have the file
-			if !isRoot[pkg.ID] {
-				continue
-			}
-			for _, pkgFile := range pkg.GoFiles {
-				if filepath.Base(query) == filepath.Base(pkgFile) {
-					response.addRoot(pkg.ID)
-					break
-				}
-			}
-		}
-	}
-	return nil
-}
-
-// modCacheRegexp splits a path in a module cache into module, module version, and package.
-var modCacheRegexp = regexp.MustCompile(`(.*)@([^/\\]*)(.*)`)
-
-func runNamedQueries(cfg *Config, driver driver, response *responseDeduper, queries []string) error {
-	// calling `go env` isn't free; bail out if there's nothing to do.
-	if len(queries) == 0 {
-		return nil
-	}
-	// Determine which directories are relevant to scan.
-	roots, modRoot, err := roots(cfg)
-	if err != nil {
-		return err
-	}
-
-	// Scan the selected directories. Simple matches, from GOPATH/GOROOT
-	// or the local module, can simply be "go list"ed. Matches from the
-	// module cache need special treatment.
-	var matchesMu sync.Mutex
-	var simpleMatches, modCacheMatches []string
-	add := func(root gopathwalk.Root, dir string) {
-		// Walk calls this concurrently; protect the result slices.
-		matchesMu.Lock()
-		defer matchesMu.Unlock()
-
-		path := dir
-		if dir != root.Path {
-			path = dir[len(root.Path)+1:]
-		}
-		if pathMatchesQueries(path, queries) {
-			switch root.Type {
-			case gopathwalk.RootModuleCache:
-				modCacheMatches = append(modCacheMatches, path)
-			case gopathwalk.RootCurrentModule:
-				// We'd need to read go.mod to find the full
-				// import path. Relative's easier.
-				rel, err := filepath.Rel(cfg.Dir, dir)
-				if err != nil {
-					// This ought to be impossible, since
-					// we found dir in the current module.
-					panic(err)
-				}
-				simpleMatches = append(simpleMatches, "./"+rel)
-			case gopathwalk.RootGOPATH, gopathwalk.RootGOROOT:
-				simpleMatches = append(simpleMatches, path)
-			}
-		}
-	}
-
-	startWalk := time.Now()
-	gopathwalk.Walk(roots, add, gopathwalk.Options{ModulesEnabled: modRoot != "", Debug: debug})
-	if debug {
-		log.Printf("%v for walk", time.Since(startWalk))
-	}
-
-	// Weird special case: the top-level package in a module will be in
-	// whatever directory the user checked the repository out into. It's
-	// more reasonable for that to not match the package name. So, if there
-	// are any Go files in the mod root, query it just to be safe.
-	if modRoot != "" {
-		rel, err := filepath.Rel(cfg.Dir, modRoot)
-		if err != nil {
-			panic(err) // See above.
-		}
-
-		files, err := ioutil.ReadDir(modRoot)
-		for _, f := range files {
-			if strings.HasSuffix(f.Name(), ".go") {
-				simpleMatches = append(simpleMatches, rel)
-				break
-			}
-		}
-	}
-
-	addResponse := func(r *driverResponse) {
-		for _, pkg := range r.Packages {
-			response.addPackage(pkg)
-			for _, name := range queries {
-				if pkg.Name == name {
-					response.addRoot(pkg.ID)
-					break
-				}
-			}
-		}
-	}
-
-	if len(simpleMatches) != 0 {
-		resp, err := driver(cfg, simpleMatches...)
-		if err != nil {
-			return err
-		}
-		addResponse(resp)
-	}
-
-	// Module cache matches are tricky. We want to avoid downloading new
-	// versions of things, so we need to use the ones present in the cache.
-	// go list doesn't accept version specifiers, so we have to write out a
-	// temporary module, and do the list in that module.
-	if len(modCacheMatches) != 0 {
-		// Collect all the matches, deduplicating by major version
-		// and preferring the newest.
-		type modInfo struct {
-			mod   string
-			major string
-		}
-		mods := make(map[modInfo]string)
-		var imports []string
-		for _, modPath := range modCacheMatches {
-			matches := modCacheRegexp.FindStringSubmatch(modPath)
-			mod, ver := filepath.ToSlash(matches[1]), matches[2]
-			importPath := filepath.ToSlash(filepath.Join(matches[1], matches[3]))
-
-			major := semver.Major(ver)
-			if prevVer, ok := mods[modInfo{mod, major}]; !ok || semver.Compare(ver, prevVer) > 0 {
-				mods[modInfo{mod, major}] = ver
-			}
-
-			imports = append(imports, importPath)
-		}
-
-		// Build the temporary module.
-		var gomod bytes.Buffer
-		gomod.WriteString("module modquery\nrequire (\n")
-		for mod, version := range mods {
-			gomod.WriteString("\t" + mod.mod + " " + version + "\n")
-		}
-		gomod.WriteString(")\n")
-
-		tmpCfg := *cfg
-
-		// We're only trying to look at stuff in the module cache, so
-		// disable the network. This should speed things up, and has
-		// prevented errors in at least one case, #28518.
-		tmpCfg.Env = append(append([]string{"GOPROXY=off"}, cfg.Env...))
-
-		var err error
-		tmpCfg.Dir, err = ioutil.TempDir("", "gopackages-modquery")
-		if err != nil {
-			return err
-		}
-		defer os.RemoveAll(tmpCfg.Dir)
-
-		if err := ioutil.WriteFile(filepath.Join(tmpCfg.Dir, "go.mod"), gomod.Bytes(), 0777); err != nil {
-			return fmt.Errorf("writing go.mod for module cache query: %v", err)
-		}
-
-		// Run the query, using the import paths calculated from the matches above.
-		resp, err := driver(&tmpCfg, imports...)
-		if err != nil {
-			return fmt.Errorf("querying module cache matches: %v", err)
-		}
-		addResponse(resp)
-	}
-
-	return nil
-}
-
-func getSizes(cfg *Config) (types.Sizes, error) {
-	return packagesdriver.GetSizesGolist(cfg.Context, cfg.BuildFlags, cfg.Env, cfg.Dir, usesExportData(cfg))
-}
-
-// roots selects the appropriate paths to walk based on the passed-in configuration,
-// particularly the environment and the presence of a go.mod in cfg.Dir's parents.
-func roots(cfg *Config) ([]gopathwalk.Root, string, error) {
-	stdout, err := invokeGo(cfg, "env", "GOROOT", "GOPATH", "GOMOD")
-	if err != nil {
-		return nil, "", err
-	}
-
-	fields := strings.Split(stdout.String(), "\n")
-	if len(fields) != 4 || len(fields[3]) != 0 {
-		return nil, "", fmt.Errorf("go env returned unexpected output: %q", stdout.String())
-	}
-	goroot, gopath, gomod := fields[0], filepath.SplitList(fields[1]), fields[2]
-	var modDir string
-	if gomod != "" {
-		modDir = filepath.Dir(gomod)
-	}
-
-	var roots []gopathwalk.Root
-	// Always add GOROOT.
-	roots = append(roots, gopathwalk.Root{filepath.Join(goroot, "/src"), gopathwalk.RootGOROOT})
-	// If modules are enabled, scan the module dir.
-	if modDir != "" {
-		roots = append(roots, gopathwalk.Root{modDir, gopathwalk.RootCurrentModule})
-	}
-	// Add either GOPATH/src or GOPATH/pkg/mod, depending on module mode.
-	for _, p := range gopath {
-		if modDir != "" {
-			roots = append(roots, gopathwalk.Root{filepath.Join(p, "/pkg/mod"), gopathwalk.RootModuleCache})
-		} else {
-			roots = append(roots, gopathwalk.Root{filepath.Join(p, "/src"), gopathwalk.RootGOPATH})
-		}
-	}
-
-	return roots, modDir, nil
-}
-
-// These functions were copied from goimports. See further documentation there.
-
-// pathMatchesQueries is adapted from pkgIsCandidate.
-// TODO: is it reasonable to do Contains here, rather than an exact match on a path component?
-func pathMatchesQueries(path string, queries []string) bool {
-	lastTwo := lastTwoComponents(path)
-	for _, query := range queries {
-		if strings.Contains(lastTwo, query) {
-			return true
-		}
-		if hasHyphenOrUpperASCII(lastTwo) && !hasHyphenOrUpperASCII(query) {
-			lastTwo = lowerASCIIAndRemoveHyphen(lastTwo)
-			if strings.Contains(lastTwo, query) {
-				return true
-			}
-		}
-	}
-	return false
-}
-
-// lastTwoComponents returns at most the last two path components
-// of v, using either / or \ as the path separator.
-func lastTwoComponents(v string) string {
-	nslash := 0
-	for i := len(v) - 1; i >= 0; i-- {
-		if v[i] == '/' || v[i] == '\\' {
-			nslash++
-			if nslash == 2 {
-				return v[i:]
-			}
-		}
-	}
-	return v
-}
-
-func hasHyphenOrUpperASCII(s string) bool {
-	for i := 0; i < len(s); i++ {
-		b := s[i]
-		if b == '-' || ('A' <= b && b <= 'Z') {
-			return true
-		}
-	}
-	return false
-}
-
-func lowerASCIIAndRemoveHyphen(s string) (ret string) {
-	buf := make([]byte, 0, len(s))
-	for i := 0; i < len(s); i++ {
-		b := s[i]
-		switch {
-		case b == '-':
-			continue
-		case 'A' <= b && b <= 'Z':
-			buf = append(buf, b+('a'-'A'))
-		default:
-			buf = append(buf, b)
-		}
-	}
-	return string(buf)
-}
-
-// Fields must match go list;
-// see $GOROOT/src/cmd/go/internal/load/pkg.go.
-type jsonPackage struct {
-	ImportPath      string
-	Dir             string
-	Name            string
-	Export          string
-	GoFiles         []string
-	CompiledGoFiles []string
-	CFiles          []string
-	CgoFiles        []string
-	CXXFiles        []string
-	MFiles          []string
-	HFiles          []string
-	FFiles          []string
-	SFiles          []string
-	SwigFiles       []string
-	SwigCXXFiles    []string
-	SysoFiles       []string
-	Imports         []string
-	ImportMap       map[string]string
-	Deps            []string
-	TestGoFiles     []string
-	TestImports     []string
-	XTestGoFiles    []string
-	XTestImports    []string
-	ForTest         string // q in a "p [q.test]" package, else ""
-	DepOnly         bool
-
-	Error *jsonPackageError
-}
-
-type jsonPackageError struct {
-	ImportStack []string
-	Pos         string
-	Err         string
-}
-
-func otherFiles(p *jsonPackage) [][]string {
-	return [][]string{p.CFiles, p.CXXFiles, p.MFiles, p.HFiles, p.FFiles, p.SFiles, p.SwigFiles, p.SwigCXXFiles, p.SysoFiles}
-}
-
-// golistDriverCurrent uses the "go list" command to expand the
-// pattern words and return metadata for the specified packages.
-// dir may be "" and env may be nil, as per os/exec.Command.
-func golistDriverCurrent(cfg *Config, words ...string) (*driverResponse, error) {
-	// go list uses the following identifiers in ImportPath and Imports:
-	//
-	// 	"p"			-- importable package or main (command)
-	//      "q.test"		-- q's test executable
-	// 	"p [q.test]"		-- variant of p as built for q's test executable
-	//	"q_test [q.test]"	-- q's external test package
-	//
-	// The packages p that are built differently for a test q.test
-	// are q itself, plus any helpers used by the external test q_test,
-	// typically including "testing" and all its dependencies.
-
-	// Run "go list" for complete
-	// information on the specified packages.
-	buf, err := invokeGo(cfg, golistargs(cfg, words)...)
-	if err != nil {
-		return nil, err
-	}
-	seen := make(map[string]*jsonPackage)
-	// Decode the JSON and convert it to Package form.
-	var response driverResponse
-	for dec := json.NewDecoder(buf); dec.More(); {
-		p := new(jsonPackage)
-		if err := dec.Decode(p); err != nil {
-			return nil, fmt.Errorf("JSON decoding failed: %v", err)
-		}
-
-		if p.ImportPath == "" {
-			// The documentation for go list says that “[e]rroneous packages will have
-			// a non-empty ImportPath”. If for some reason it comes back empty, we
-			// prefer to error out rather than silently discarding data or handing
-			// back a package without any way to refer to it.
-			if p.Error != nil {
-				return nil, Error{
-					Pos: p.Error.Pos,
-					Msg: p.Error.Err,
-				}
-			}
-			return nil, fmt.Errorf("package missing import path: %+v", p)
-		}
-
-		if old, found := seen[p.ImportPath]; found {
-			if !reflect.DeepEqual(p, old) {
-				return nil, fmt.Errorf("internal error: go list gives conflicting information for package %v", p.ImportPath)
-			}
-			// skip the duplicate
-			continue
-		}
-		seen[p.ImportPath] = p
-
-		pkg := &Package{
-			Name:            p.Name,
-			ID:              p.ImportPath,
-			GoFiles:         absJoin(p.Dir, p.GoFiles, p.CgoFiles),
-			CompiledGoFiles: absJoin(p.Dir, p.CompiledGoFiles),
-			OtherFiles:      absJoin(p.Dir, otherFiles(p)...),
-		}
-
-		// Work around https://golang.org/issue/28749:
-		// cmd/go puts assembly, C, and C++ files in CompiledGoFiles.
-		// Filter out any elements of CompiledGoFiles that are also in OtherFiles.
-		// We have to keep this workaround in place until go1.12 is a distant memory.
-		if len(pkg.OtherFiles) > 0 {
-			other := make(map[string]bool, len(pkg.OtherFiles))
-			for _, f := range pkg.OtherFiles {
-				other[f] = true
-			}
-
-			out := pkg.CompiledGoFiles[:0]
-			for _, f := range pkg.CompiledGoFiles {
-				if other[f] {
-					continue
-				}
-				out = append(out, f)
-			}
-			pkg.CompiledGoFiles = out
-		}
-
-		// Extract the PkgPath from the package's ID.
-		if i := strings.IndexByte(pkg.ID, ' '); i >= 0 {
-			pkg.PkgPath = pkg.ID[:i]
-		} else {
-			pkg.PkgPath = pkg.ID
-		}
-
-		if pkg.PkgPath == "unsafe" {
-			pkg.GoFiles = nil // ignore fake unsafe.go file
-		}
-
-		// Assume go list emits only absolute paths for Dir.
-		if p.Dir != "" && !filepath.IsAbs(p.Dir) {
-			log.Fatalf("internal error: go list returned non-absolute Package.Dir: %s", p.Dir)
-		}
-
-		if p.Export != "" && !filepath.IsAbs(p.Export) {
-			pkg.ExportFile = filepath.Join(p.Dir, p.Export)
-		} else {
-			pkg.ExportFile = p.Export
-		}
-
-		// imports
-		//
-		// Imports contains the IDs of all imported packages.
-		// ImportsMap records (path, ID) only where they differ.
-		ids := make(map[string]bool)
-		for _, id := range p.Imports {
-			ids[id] = true
-		}
-		pkg.Imports = make(map[string]*Package)
-		for path, id := range p.ImportMap {
-			pkg.Imports[path] = &Package{ID: id} // non-identity import
-			delete(ids, id)
-		}
-		for id := range ids {
-			if id == "C" {
-				continue
-			}
-
-			pkg.Imports[id] = &Package{ID: id} // identity import
-		}
-		if !p.DepOnly {
-			response.Roots = append(response.Roots, pkg.ID)
-		}
-
-		// Work around for pre-go.1.11 versions of go list.
-		// TODO(matloob): they should be handled by the fallback.
-		// Can we delete this?
-		if len(pkg.CompiledGoFiles) == 0 {
-			pkg.CompiledGoFiles = pkg.GoFiles
-		}
-
-		if p.Error != nil {
-			pkg.Errors = append(pkg.Errors, Error{
-				Pos: p.Error.Pos,
-				Msg: p.Error.Err,
-			})
-		}
-
-		response.Packages = append(response.Packages, pkg)
-	}
-
-	return &response, nil
-}
-
-// absJoin absolutizes and flattens the lists of files.
-func absJoin(dir string, fileses ...[]string) (res []string) {
-	for _, files := range fileses {
-		for _, file := range files {
-			if !filepath.IsAbs(file) {
-				file = filepath.Join(dir, file)
-			}
-			res = append(res, file)
-		}
-	}
-	return res
-}
-
-func golistargs(cfg *Config, words []string) []string {
-	const findFlags = NeedImports | NeedTypes | NeedSyntax | NeedTypesInfo
-	fullargs := []string{
-		"list", "-e", "-json",
-		fmt.Sprintf("-compiled=%t", cfg.Mode&(NeedCompiledGoFiles|NeedSyntax|NeedTypesInfo|NeedTypesSizes) != 0),
-		fmt.Sprintf("-test=%t", cfg.Tests),
-		fmt.Sprintf("-export=%t", usesExportData(cfg)),
-		fmt.Sprintf("-deps=%t", cfg.Mode&NeedDeps != 0),
-		// go list doesn't let you pass -test and -find together,
-		// probably because you'd just get the TestMain.
-		fmt.Sprintf("-find=%t", !cfg.Tests && cfg.Mode&findFlags == 0),
-	}
-	fullargs = append(fullargs, cfg.BuildFlags...)
-	fullargs = append(fullargs, "--")
-	fullargs = append(fullargs, words...)
-	return fullargs
-}
-
-// invokeGo returns the stdout of a go command invocation.
-func invokeGo(cfg *Config, args ...string) (*bytes.Buffer, error) {
-	stdout := new(bytes.Buffer)
-	stderr := new(bytes.Buffer)
-	cmd := exec.CommandContext(cfg.Context, "go", args...)
-	// On darwin the cwd gets resolved to the real path, which breaks anything that
-	// expects the working directory to keep the original path, including the
-	// go command when dealing with modules.
-	// The Go stdlib has a special feature where if the cwd and the PWD are the
-	// same node then it trusts the PWD, so by setting it in the env for the child
-	// process we fix up all the paths returned by the go command.
-	cmd.Env = append(append([]string{}, cfg.Env...), "PWD="+cfg.Dir)
-	cmd.Dir = cfg.Dir
-	cmd.Stdout = stdout
-	cmd.Stderr = stderr
-	if debug {
-		defer func(start time.Time) {
-			log.Printf("%s for %v, stderr: <<%s>>\n", time.Since(start), cmdDebugStr(cmd, args...), stderr)
-		}(time.Now())
-	}
-
-	if err := cmd.Run(); err != nil {
-		// Check for 'go' executable not being found.
-		if ee, ok := err.(*exec.Error); ok && ee.Err == exec.ErrNotFound {
-			return nil, fmt.Errorf("'go list' driver requires 'go', but %s", exec.ErrNotFound)
-		}
-
-		exitErr, ok := err.(*exec.ExitError)
-		if !ok {
-			// Catastrophic error:
-			// - context cancellation
-			return nil, fmt.Errorf("couldn't exec 'go %v': %s %T", args, err, err)
-		}
-
-		// Old go version?
-		if strings.Contains(stderr.String(), "flag provided but not defined") {
-			return nil, goTooOldError{fmt.Errorf("unsupported version of go: %s: %s", exitErr, stderr)}
-		}
-
-		// This error only appears in stderr. See golang.org/cl/166398 for a fix in go list to show
-		// the error in the Err section of stdout in case -e option is provided.
-		// This fix is provided for backwards compatibility.
-		if len(stderr.String()) > 0 && strings.Contains(stderr.String(), "named files must be .go files") {
-			output := fmt.Sprintf(`{"ImportPath": "","Incomplete": true,"Error": {"Pos": "","Err": %s}}`,
-				strconv.Quote(strings.Trim(stderr.String(), "\n")))
-			return bytes.NewBufferString(output), nil
-		}
-
-		// Export mode entails a build.
-		// If that build fails, errors appear on stderr
-		// (despite the -e flag) and the Export field is blank.
-		// Do not fail in that case.
-		// The same is true if an ad-hoc package given to go list doesn't exist.
-		// TODO(matloob): Remove these once we can depend on go list to exit with a zero status with -e even when
-		// packages don't exist or a build fails.
-		if !usesExportData(cfg) && !containsGoFile(args) {
-			return nil, fmt.Errorf("go %v: %s: %s", args, exitErr, stderr)
-		}
-	}
-
-	// As of writing, go list -export prints some non-fatal compilation
-	// errors to stderr, even with -e set. We would prefer that it put
-	// them in the Package.Error JSON (see https://golang.org/issue/26319).
-	// In the meantime, there's nowhere good to put them, but they can
-	// be useful for debugging. Print them if $GOPACKAGESPRINTGOLISTERRORS
-	// is set.
-	if len(stderr.Bytes()) != 0 && os.Getenv("GOPACKAGESPRINTGOLISTERRORS") != "" {
-		fmt.Fprintf(os.Stderr, "%s stderr: <<%s>>\n", cmdDebugStr(cmd, args...), stderr)
-	}
-
-	// debugging
-	if false {
-		fmt.Fprintf(os.Stderr, "%s stdout: <<%s>>\n", cmdDebugStr(cmd, args...), stdout)
-	}
-
-	return stdout, nil
-}
-
-func containsGoFile(s []string) bool {
-	for _, f := range s {
-		if strings.HasSuffix(f, ".go") {
-			return true
-		}
-	}
-	return false
-}
-
-func cmdDebugStr(cmd *exec.Cmd, args ...string) string {
-	env := make(map[string]string)
-	for _, kv := range cmd.Env {
-		split := strings.Split(kv, "=")
-		k, v := split[0], split[1]
-		env[k] = v
-	}
-	var quotedArgs []string
-	for _, arg := range args {
-		quotedArgs = append(quotedArgs, strconv.Quote(arg))
-	}
-
-	return fmt.Sprintf("GOROOT=%v GOPATH=%v GO111MODULE=%v PWD=%v go %s", env["GOROOT"], env["GOPATH"], env["GO111MODULE"], env["PWD"], strings.Join(quotedArgs, " "))
-}

vendor/golang.org/x/tools/go/packages/golist_overlay.go

@@ -1,104 +0,0 @@
-package packages
-
-import (
-	"go/parser"
-	"go/token"
-	"path/filepath"
-	"strconv"
-	"strings"
-)
-
-// processGolistOverlay provides rudimentary support for adding
-// files that don't exist on disk to an overlay. The results can be
-// sometimes incorrect.
-// TODO(matloob): Handle unsupported cases, including the following:
-// - test files
-// - adding test and non-test files to test variants of packages
-// - determining the correct package to add given a new import path
-// - creating packages that don't exist
-func processGolistOverlay(cfg *Config, response *driverResponse) (modifiedPkgs, needPkgs []string, err error) {
-	havePkgs := make(map[string]string) // importPath -> non-test package ID
-	needPkgsSet := make(map[string]bool)
-	modifiedPkgsSet := make(map[string]bool)
-
-	for _, pkg := range response.Packages {
-		// This is an approximation of import path to id. This can be
-		// wrong for tests, vendored packages, and a number of other cases.
-		havePkgs[pkg.PkgPath] = pkg.ID
-	}
-
-outer:
-	for path, contents := range cfg.Overlay {
-		base := filepath.Base(path)
-		if strings.HasSuffix(path, "_test.go") {
-			// Overlays don't support adding new test files yet.
-			// TODO(matloob): support adding new test files.
-			continue
-		}
-		dir := filepath.Dir(path)
-		for _, pkg := range response.Packages {
-			var dirContains, fileExists bool
-			for _, f := range pkg.GoFiles {
-				if sameFile(filepath.Dir(f), dir) {
-					dirContains = true
-				}
-				if filepath.Base(f) == base {
-					fileExists = true
-				}
-			}
-			if dirContains {
-				if !fileExists {
-					pkg.GoFiles = append(pkg.GoFiles, path) // TODO(matloob): should the file just be added to GoFiles?
-					pkg.CompiledGoFiles = append(pkg.CompiledGoFiles, path)
-					modifiedPkgsSet[pkg.ID] = true
-				}
-				imports, err := extractImports(path, contents)
-				if err != nil {
-					// Let the parser or type checker report errors later.
-					continue outer
-				}
-				for _, imp := range imports {
-					_, found := pkg.Imports[imp]
-					if !found {
-						needPkgsSet[imp] = true
-						// TODO(matloob): Handle cases when the following block isn't correct.
-						// These include imports of test variants, imports of vendored packages, etc.
-						id, ok := havePkgs[imp]
-						if !ok {
-							id = imp
-						}
-						pkg.Imports[imp] = &Package{ID: id}
-					}
-				}
-				continue outer
-			}
-		}
-	}
-
-	needPkgs = make([]string, 0, len(needPkgsSet))
-	for pkg := range needPkgsSet {
-		needPkgs = append(needPkgs, pkg)
-	}
-	modifiedPkgs = make([]string, 0, len(modifiedPkgsSet))
-	for pkg := range modifiedPkgsSet {
-		modifiedPkgs = append(modifiedPkgs, pkg)
-	}
-	return modifiedPkgs, needPkgs, err
-}
-
-func extractImports(filename string, contents []byte) ([]string, error) {
-	f, err := parser.ParseFile(token.NewFileSet(), filename, contents, parser.ImportsOnly) // TODO(matloob): reuse fileset?
-	if err != nil {
-		return nil, err
-	}
-	var res []string
-	for _, imp := range f.Imports {
-		quotedPath := imp.Path.Value
-		path, err := strconv.Unquote(quotedPath)
-		if err != nil {
-			return nil, err
-		}
-		res = append(res, path)
-	}
-	return res, nil
-}

vendor/golang.org/x/tools/go/packages/visit.go

@@ -1,55 +0,0 @@
-package packages
-
-import (
-	"fmt"
-	"os"
-	"sort"
-)
-
-// Visit visits all the packages in the import graph whose roots are
-// pkgs, calling the optional pre function the first time each package
-// is encountered (preorder), and the optional post function after a
-// package's dependencies have been visited (postorder).
-// The boolean result of pre(pkg) determines whether
-// the imports of package pkg are visited.
-func Visit(pkgs []*Package, pre func(*Package) bool, post func(*Package)) {
-	seen := make(map[*Package]bool)
-	var visit func(*Package)
-	visit = func(pkg *Package) {
-		if !seen[pkg] {
-			seen[pkg] = true
-
-			if pre == nil || pre(pkg) {
-				paths := make([]string, 0, len(pkg.Imports))
-				for path := range pkg.Imports {
-					paths = append(paths, path)
-				}
-				sort.Strings(paths) // Imports is a map, this makes visit stable
-				for _, path := range paths {
-					visit(pkg.Imports[path])
-				}
-			}
-
-			if post != nil {
-				post(pkg)
-			}
-		}
-	}
-	for _, pkg := range pkgs {
-		visit(pkg)
-	}
-}
-
-// PrintErrors prints to os.Stderr the accumulated errors of all
-// packages in the import graph rooted at pkgs, dependencies first.
-// PrintErrors returns the number of errors printed.
-func PrintErrors(pkgs []*Package) int {
-	var n int
-	Visit(pkgs, nil, func(pkg *Package) {
-		for _, err := range pkg.Errors {
-			fmt.Fprintln(os.Stderr, err)
-			n++
-		}
-	})
-	return n
-}

vendor/golang.org/x/tools/imports/forward.go

@@ -0,0 +1,77 @@
+// Copyright 2019 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Package imports implements a Go pretty-printer (like package "go/format")
+// that also adds or removes import statements as necessary.
+package imports // import "golang.org/x/tools/imports"
+
+import (
+	"io/ioutil"
+	"log"
+
+	"golang.org/x/tools/internal/gocommand"
+	intimp "golang.org/x/tools/internal/imports"
+)
+
+// Options specifies options for processing files.
+type Options struct {
+	Fragment  bool // Accept fragment of a source file (no package statement)
+	AllErrors bool // Report all errors (not just the first 10 on different lines)
+
+	Comments  bool // Print comments (true if nil *Options provided)
+	TabIndent bool // Use tabs for indent (true if nil *Options provided)
+	TabWidth  int  // Tab width (8 if nil *Options provided)
+
+	FormatOnly bool // Disable the insertion and deletion of imports
+}
+
+// Debug controls verbose logging.
+var Debug = false
+
+// LocalPrefix is a comma-separated string of import path prefixes, which, if
+// set, instructs Process to sort the import paths with the given prefixes
+// into another group after 3rd-party packages.
+var LocalPrefix string
+
+// Process formats and adjusts imports for the provided file.
+// If opt is nil the defaults are used, and if src is nil the source
+// is read from the filesystem.
+//
+// Note that filename's directory influences which imports can be chosen,
+// so it is important that filename be accurate.
+// To process data ``as if'' it were in filename, pass the data as a non-nil src.
+func Process(filename string, src []byte, opt *Options) ([]byte, error) {
+	var err error
+	if src == nil {
+		src, err = ioutil.ReadFile(filename)
+		if err != nil {
+			return nil, err
+		}
+	}
+	if opt == nil {
+		opt = &Options{Comments: true, TabIndent: true, TabWidth: 8}
+	}
+	intopt := &intimp.Options{
+		Env: &intimp.ProcessEnv{
+			GocmdRunner: &gocommand.Runner{},
+		},
+		LocalPrefix: LocalPrefix,
+		AllErrors:   opt.AllErrors,
+		Comments:    opt.Comments,
+		FormatOnly:  opt.FormatOnly,
+		Fragment:    opt.Fragment,
+		TabIndent:   opt.TabIndent,
+		TabWidth:    opt.TabWidth,
+	}
+	if Debug {
+		intopt.Env.Logf = log.Printf
+	}
+	return intimp.Process(filename, src, intopt)
+}
+
+// VendorlessPath returns the devendorized version of the import path ipath.
+// For example, VendorlessPath("foo/bar/vendor/a/b") returns "a/b".
+func VendorlessPath(ipath string) string {
+	return intimp.VendorlessPath(ipath)
+}

vendor/golang.org/x/tools/imports/mod.go

@@ -1,355 +0,0 @@
-package imports
-
-import (
-	"bytes"
-	"encoding/json"
-	"io/ioutil"
-	"log"
-	"os"
-	"path"
-	"path/filepath"
-	"regexp"
-	"sort"
-	"strconv"
-	"strings"
-	"sync"
-	"time"
-
-	"golang.org/x/tools/internal/gopathwalk"
-	"golang.org/x/tools/internal/module"
-)
-
-// moduleResolver implements resolver for modules using the go command as little
-// as feasible.
-type moduleResolver struct {
-	env *fixEnv
-
-	initialized   bool
-	main          *moduleJSON
-	modsByModPath []*moduleJSON // All modules, ordered by # of path components in module Path...
-	modsByDir     []*moduleJSON // ...or Dir.
-}
-
-type moduleJSON struct {
-	Path     string           // module path
-	Version  string           // module version
-	Versions []string         // available module versions (with -versions)
-	Replace  *moduleJSON      // replaced by this module
-	Time     *time.Time       // time version was created
-	Update   *moduleJSON      // available update, if any (with -u)
-	Main     bool             // is this the main module?
-	Indirect bool             // is this module only an indirect dependency of main module?
-	Dir      string           // directory holding files for this module, if any
-	GoMod    string           // path to go.mod file for this module, if any
-	Error    *moduleErrorJSON // error loading module
-}
-
-type moduleErrorJSON struct {
-	Err string // the error itself
-}
-
-func (r *moduleResolver) init() error {
-	if r.initialized {
-		return nil
-	}
-	stdout, err := r.env.invokeGo("list", "-m", "-json", "...")
-	if err != nil {
-		return err
-	}
-	for dec := json.NewDecoder(stdout); dec.More(); {
-		mod := &moduleJSON{}
-		if err := dec.Decode(mod); err != nil {
-			return err
-		}
-		if mod.Dir == "" {
-			if Debug {
-				log.Printf("module %v has not been downloaded and will be ignored", mod.Path)
-			}
-			// Can't do anything with a module that's not downloaded.
-			continue
-		}
-		r.modsByModPath = append(r.modsByModPath, mod)
-		r.modsByDir = append(r.modsByDir, mod)
-		if mod.Main {
-			r.main = mod
-		}
-	}
-
-	sort.Slice(r.modsByModPath, func(i, j int) bool {
-		count := func(x int) int {
-			return strings.Count(r.modsByModPath[x].Path, "/")
-		}
-		return count(j) < count(i) // descending order
-	})
-	sort.Slice(r.modsByDir, func(i, j int) bool {
-		count := func(x int) int {
-			return strings.Count(r.modsByDir[x].Dir, "/")
-		}
-		return count(j) < count(i) // descending order
-	})
-
-	r.initialized = true
-	return nil
-}
-
-// findPackage returns the module and directory that contains the package at
-// the given import path, or returns nil, "" if no module is in scope.
-func (r *moduleResolver) findPackage(importPath string) (*moduleJSON, string) {
-	for _, m := range r.modsByModPath {
-		if !strings.HasPrefix(importPath, m.Path) {
-			continue
-		}
-		pathInModule := importPath[len(m.Path):]
-		pkgDir := filepath.Join(m.Dir, pathInModule)
-		if dirIsNestedModule(pkgDir, m) {
-			continue
-		}
-
-		pkgFiles, err := ioutil.ReadDir(pkgDir)
-		if err != nil {
-			continue
-		}
-
-		// A module only contains a package if it has buildable go
-		// files in that directory. If not, it could be provided by an
-		// outer module. See #29736.
-		for _, fi := range pkgFiles {
-			if ok, _ := r.env.buildContext().MatchFile(pkgDir, fi.Name()); ok {
-				return m, pkgDir
-			}
-		}
-	}
-	return nil, ""
-}
-
-// findModuleByDir returns the module that contains dir, or nil if no such
-// module is in scope.
-func (r *moduleResolver) findModuleByDir(dir string) *moduleJSON {
-	// This is quite tricky and may not be correct. dir could be:
-	// - a package in the main module.
-	// - a replace target underneath the main module's directory.
-	//    - a nested module in the above.
-	// - a replace target somewhere totally random.
-	//    - a nested module in the above.
-	// - in the mod cache.
-	// - in /vendor/ in -mod=vendor mode.
-	//    - nested module? Dunno.
-	// Rumor has it that replace targets cannot contain other replace targets.
-	for _, m := range r.modsByDir {
-		if !strings.HasPrefix(dir, m.Dir) {
-			continue
-		}
-
-		if dirIsNestedModule(dir, m) {
-			continue
-		}
-
-		return m
-	}
-	return nil
-}
-
-// dirIsNestedModule reports if dir is contained in a nested module underneath
-// mod, not actually in mod.
-func dirIsNestedModule(dir string, mod *moduleJSON) bool {
-	if !strings.HasPrefix(dir, mod.Dir) {
-		return false
-	}
-	mf := findModFile(dir)
-	if mf == "" {
-		return false
-	}
-	return filepath.Dir(mf) != mod.Dir
-}
-
-func findModFile(dir string) string {
-	for {
-		f := filepath.Join(dir, "go.mod")
-		info, err := os.Stat(f)
-		if err == nil && !info.IsDir() {
-			return f
-		}
-		d := filepath.Dir(dir)
-		if len(d) >= len(dir) {
-			return "" // reached top of file system, no go.mod
-		}
-		dir = d
-	}
-}
-
-func (r *moduleResolver) loadPackageNames(importPaths []string, srcDir string) (map[string]string, error) {
-	if err := r.init(); err != nil {
-		return nil, err
-	}
-	names := map[string]string{}
-	for _, path := range importPaths {
-		_, packageDir := r.findPackage(path)
-		if packageDir == "" {
-			continue
-		}
-		name, err := packageDirToName(packageDir)
-		if err != nil {
-			continue
-		}
-		names[path] = name
-	}
-	return names, nil
-}
-
-func (r *moduleResolver) scan(_ references) ([]*pkg, error) {
-	if err := r.init(); err != nil {
-		return nil, err
-	}
-
-	// Walk GOROOT, GOPATH/pkg/mod, and the main module.
-	roots := []gopathwalk.Root{
-		{filepath.Join(r.env.GOROOT, "/src"), gopathwalk.RootGOROOT},
-	}
-	if r.main != nil {
-		roots = append(roots, gopathwalk.Root{r.main.Dir, gopathwalk.RootCurrentModule})
-	}
-	for _, p := range filepath.SplitList(r.env.GOPATH) {
-		roots = append(roots, gopathwalk.Root{filepath.Join(p, "/pkg/mod"), gopathwalk.RootModuleCache})
-	}
-
-	// Walk replace targets, just in case they're not in any of the above.
-	for _, mod := range r.modsByModPath {
-		if mod.Replace != nil {
-			roots = append(roots, gopathwalk.Root{mod.Dir, gopathwalk.RootOther})
-		}
-	}
-
-	var result []*pkg
-	dupCheck := make(map[string]bool)
-	var mu sync.Mutex
-
-	gopathwalk.Walk(roots, func(root gopathwalk.Root, dir string) {
-		mu.Lock()
-		defer mu.Unlock()
-
-		if _, dup := dupCheck[dir]; dup {
-			return
-		}
-
-		dupCheck[dir] = true
-
-		subdir := ""
-		if dir != root.Path {
-			subdir = dir[len(root.Path)+len("/"):]
-		}
-		importPath := filepath.ToSlash(subdir)
-		if strings.HasPrefix(importPath, "vendor/") {
-			// Ignore vendor dirs. If -mod=vendor is on, then things
-			// should mostly just work, but when it's not vendor/
-			// is a mess. There's no easy way to tell if it's on.
-			// We can still find things in the mod cache and
-			// map them into /vendor when -mod=vendor is on.
-			return
-		}
-		switch root.Type {
-		case gopathwalk.RootCurrentModule:
-			importPath = path.Join(r.main.Path, filepath.ToSlash(subdir))
-		case gopathwalk.RootModuleCache:
-			matches := modCacheRegexp.FindStringSubmatch(subdir)
-			modPath, err := module.DecodePath(filepath.ToSlash(matches[1]))
-			if err != nil {
-				if Debug {
-					log.Printf("decoding module cache path %q: %v", subdir, err)
-				}
-				return
-			}
-			importPath = path.Join(modPath, filepath.ToSlash(matches[3]))
-		case gopathwalk.RootGOROOT:
-			importPath = subdir
-		}
-
-		// Check if the directory is underneath a module that's in scope.
-		if mod := r.findModuleByDir(dir); mod != nil {
-			// It is. If dir is the target of a replace directive,
-			// our guessed import path is wrong. Use the real one.
-			if mod.Dir == dir {
-				importPath = mod.Path
-			} else {
-				dirInMod := dir[len(mod.Dir)+len("/"):]
-				importPath = path.Join(mod.Path, filepath.ToSlash(dirInMod))
-			}
-		} else {
-			// The package is in an unknown module. Check that it's
-			// not obviously impossible to import.
-			var modFile string
-			switch root.Type {
-			case gopathwalk.RootModuleCache:
-				matches := modCacheRegexp.FindStringSubmatch(subdir)
-				modFile = filepath.Join(matches[1], "@", matches[2], "go.mod")
-			default:
-				modFile = findModFile(dir)
-			}
-
-			modBytes, err := ioutil.ReadFile(modFile)
-			if err == nil && !strings.HasPrefix(importPath, modulePath(modBytes)) {
-				// The module's declared path does not match
-				// its expected path. It probably needs a
-				// replace directive we don't have.
-				return
-			}
-		}
-		// We may have discovered a package that has a different version
-		// in scope already. Canonicalize to that one if possible.
-		if _, canonicalDir := r.findPackage(importPath); canonicalDir != "" {
-			dir = canonicalDir
-		}
-
-		result = append(result, &pkg{
-			importPathShort: VendorlessPath(importPath),
-			dir:             dir,
-		})
-	}, gopathwalk.Options{Debug: Debug, ModulesEnabled: true})
-	return result, nil
-}
-
-// modCacheRegexp splits a path in a module cache into module, module version, and package.
-var modCacheRegexp = regexp.MustCompile(`(.*)@([^/\\]*)(.*)`)
-
-var (
-	slashSlash = []byte("//")
-	moduleStr  = []byte("module")
-)
-
-// modulePath returns the module path from the gomod file text.
-// If it cannot find a module path, it returns an empty string.
-// It is tolerant of unrelated problems in the go.mod file.
-//
-// Copied from cmd/go/internal/modfile.
-func modulePath(mod []byte) string {
-	for len(mod) > 0 {
-		line := mod
-		mod = nil
-		if i := bytes.IndexByte(line, '\n'); i >= 0 {
-			line, mod = line[:i], line[i+1:]
-		}
-		if i := bytes.Index(line, slashSlash); i >= 0 {
-			line = line[:i]
-		}
-		line = bytes.TrimSpace(line)
-		if !bytes.HasPrefix(line, moduleStr) {
-			continue
-		}
-		line = line[len(moduleStr):]
-		n := len(line)
-		line = bytes.TrimSpace(line)
-		if len(line) == n || len(line) == 0 {
-			continue
-		}
-
-		if line[0] == '"' || line[0] == '`' {
-			p, err := strconv.Unquote(string(line))
-			if err != nil {
-				return "" // malformed quoted string or multiline module path
-			}
-			return p
-		}
-
-		return string(line)
-	}
-	return "" // missing module path
-}

vendor/golang.org/x/tools/internal/event/core/event.go

@@ -0,0 +1,85 @@
+// Copyright 2019 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Package core provides support for event based telemetry.
+package core
+
+import (
+	"fmt"
+	"time"
+
+	"golang.org/x/tools/internal/event/label"
+)
+
+// Event holds the information about an event of note that occurred.
+type Event struct {
+	at time.Time
+
+	// As events are often on the stack, storing the first few labels directly
+	// in the event can avoid an allocation at all for the very common cases of
+	// simple events.
+	// The length needs to be large enough to cope with the majority of events
+	// but no so large as to cause undue stack pressure.
+	// A log message with two values will use 3 labels (one for each value and
+	// one for the message itself).
+
+	static  [3]label.Label // inline storage for the first few labels
+	dynamic []label.Label  // dynamically sized storage for remaining labels
+}
+
+// eventLabelMap implements label.Map for a the labels of an Event.
+type eventLabelMap struct {
+	event Event
+}
+
+func (ev Event) At() time.Time { return ev.at }
+
+func (ev Event) Format(f fmt.State, r rune) {
+	if !ev.at.IsZero() {
+		fmt.Fprint(f, ev.at.Format("2006/01/02 15:04:05 "))
+	}
+	for index := 0; ev.Valid(index); index++ {
+		if l := ev.Label(index); l.Valid() {
+			fmt.Fprintf(f, "\n\t%v", l)
+		}
+	}
+}
+
+func (ev Event) Valid(index int) bool {
+	return index >= 0 && index < len(ev.static)+len(ev.dynamic)
+}
+
+func (ev Event) Label(index int) label.Label {
+	if index < len(ev.static) {
+		return ev.static[index]
+	}
+	return ev.dynamic[index-len(ev.static)]
+}
+
+func (ev Event) Find(key label.Key) label.Label {
+	for _, l := range ev.static {
+		if l.Key() == key {
+			return l
+		}
+	}
+	for _, l := range ev.dynamic {
+		if l.Key() == key {
+			return l
+		}
+	}
+	return label.Label{}
+}
+
+func MakeEvent(static [3]label.Label, labels []label.Label) Event {
+	return Event{
+		static:  static,
+		dynamic: labels,
+	}
+}
+
+// CloneEvent event returns a copy of the event with the time adjusted to at.
+func CloneEvent(ev Event, at time.Time) Event {
+	ev.at = at
+	return ev
+}

vendor/golang.org/x/tools/internal/event/core/export.go

@@ -0,0 +1,70 @@
+// Copyright 2019 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package core
+
+import (
+	"context"
+	"sync/atomic"
+	"time"
+	"unsafe"
+
+	"golang.org/x/tools/internal/event/label"
+)
+
+// Exporter is a function that handles events.
+// It may return a modified context and event.
+type Exporter func(context.Context, Event, label.Map) context.Context
+
+var (
+	exporter unsafe.Pointer
+)
+
+// SetExporter sets the global exporter function that handles all events.
+// The exporter is called synchronously from the event call site, so it should
+// return quickly so as not to hold up user code.
+func SetExporter(e Exporter) {
+	p := unsafe.Pointer(&e)
+	if e == nil {
+		// &e is always valid, and so p is always valid, but for the early abort
+		// of ProcessEvent to be efficient it needs to make the nil check on the
+		// pointer without having to dereference it, so we make the nil function
+		// also a nil pointer
+		p = nil
+	}
+	atomic.StorePointer(&exporter, p)
+}
+
+// deliver is called to deliver an event to the supplied exporter.
+// it will fill in the time.
+func deliver(ctx context.Context, exporter Exporter, ev Event) context.Context {
+	// add the current time to the event
+	ev.at = time.Now()
+	// hand the event off to the current exporter
+	return exporter(ctx, ev, ev)
+}
+
+// Export is called to deliver an event to the global exporter if set.
+func Export(ctx context.Context, ev Event) context.Context {
+	// get the global exporter and abort early if there is not one
+	exporterPtr := (*Exporter)(atomic.LoadPointer(&exporter))
+	if exporterPtr == nil {
+		return ctx
+	}
+	return deliver(ctx, *exporterPtr, ev)
+}
+
+// ExportPair is called to deliver a start event to the supplied exporter.
+// It also returns a function that will deliver the end event to the same
+// exporter.
+// It will fill in the time.
+func ExportPair(ctx context.Context, begin, end Event) (context.Context, func()) {
+	// get the global exporter and abort early if there is not one
+	exporterPtr := (*Exporter)(atomic.LoadPointer(&exporter))
+	if exporterPtr == nil {
+		return ctx, func() {}
+	}
+	ctx = deliver(ctx, *exporterPtr, begin)
+	return ctx, func() { deliver(ctx, *exporterPtr, end) }
+}

vendor/golang.org/x/tools/internal/event/core/fast.go

@@ -0,0 +1,77 @@
+// Copyright 2019 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package core
+
+import (
+	"context"
+
+	"golang.org/x/tools/internal/event/keys"
+	"golang.org/x/tools/internal/event/label"
+)
+
+// Log1 takes a message and one label delivers a log event to the exporter.
+// It is a customized version of Print that is faster and does no allocation.
+func Log1(ctx context.Context, message string, t1 label.Label) {
+	Export(ctx, MakeEvent([3]label.Label{
+		keys.Msg.Of(message),
+		t1,
+	}, nil))
+}
+
+// Log2 takes a message and two labels and delivers a log event to the exporter.
+// It is a customized version of Print that is faster and does no allocation.
+func Log2(ctx context.Context, message string, t1 label.Label, t2 label.Label) {
+	Export(ctx, MakeEvent([3]label.Label{
+		keys.Msg.Of(message),
+		t1,
+		t2,
+	}, nil))
+}
+
+// Metric1 sends a label event to the exporter with the supplied labels.
+func Metric1(ctx context.Context, t1 label.Label) context.Context {
+	return Export(ctx, MakeEvent([3]label.Label{
+		keys.Metric.New(),
+		t1,
+	}, nil))
+}
+
+// Metric2 sends a label event to the exporter with the supplied labels.
+func Metric2(ctx context.Context, t1, t2 label.Label) context.Context {
+	return Export(ctx, MakeEvent([3]label.Label{
+		keys.Metric.New(),
+		t1,
+		t2,
+	}, nil))
+}
+
+// Start1 sends a span start event with the supplied label list to the exporter.
+// It also returns a function that will end the span, which should normally be
+// deferred.
+func Start1(ctx context.Context, name string, t1 label.Label) (context.Context, func()) {
+	return ExportPair(ctx,
+		MakeEvent([3]label.Label{
+			keys.Start.Of(name),
+			t1,
+		}, nil),
+		MakeEvent([3]label.Label{
+			keys.End.New(),
+		}, nil))
+}
+
+// Start2 sends a span start event with the supplied label list to the exporter.
+// It also returns a function that will end the span, which should normally be
+// deferred.
+func Start2(ctx context.Context, name string, t1, t2 label.Label) (context.Context, func()) {
+	return ExportPair(ctx,
+		MakeEvent([3]label.Label{
+			keys.Start.Of(name),
+			t1,
+			t2,
+		}, nil),
+		MakeEvent([3]label.Label{
+			keys.End.New(),
+		}, nil))
+}

vendor/golang.org/x/tools/internal/event/doc.go

@@ -0,0 +1,7 @@
+// Copyright 2019 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Package event provides a set of packages that cover the main
+// concepts of telemetry in an implementation agnostic way.
+package event

vendor/golang.org/x/tools/internal/event/event.go

@@ -0,0 +1,127 @@
+// Copyright 2019 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package event
+
+import (
+	"context"
+
+	"golang.org/x/tools/internal/event/core"
+	"golang.org/x/tools/internal/event/keys"
+	"golang.org/x/tools/internal/event/label"
+)
+
+// Exporter is a function that handles events.
+// It may return a modified context and event.
+type Exporter func(context.Context, core.Event, label.Map) context.Context
+
+// SetExporter sets the global exporter function that handles all events.
+// The exporter is called synchronously from the event call site, so it should
+// return quickly so as not to hold up user code.
+func SetExporter(e Exporter) {
+	core.SetExporter(core.Exporter(e))
+}
+
+// Log takes a message and a label list and combines them into a single event
+// before delivering them to the exporter.
+func Log(ctx context.Context, message string, labels ...label.Label) {
+	core.Export(ctx, core.MakeEvent([3]label.Label{
+		keys.Msg.Of(message),
+	}, labels))
+}
+
+// IsLog returns true if the event was built by the Log function.
+// It is intended to be used in exporters to identify the semantics of the
+// event when deciding what to do with it.
+func IsLog(ev core.Event) bool {
+	return ev.Label(0).Key() == keys.Msg
+}
+
+// Error takes a message and a label list and combines them into a single event
+// before delivering them to the exporter. It captures the error in the
+// delivered event.
+func Error(ctx context.Context, message string, err error, labels ...label.Label) {
+	core.Export(ctx, core.MakeEvent([3]label.Label{
+		keys.Msg.Of(message),
+		keys.Err.Of(err),
+	}, labels))
+}
+
+// IsError returns true if the event was built by the Error function.
+// It is intended to be used in exporters to identify the semantics of the
+// event when deciding what to do with it.
+func IsError(ev core.Event) bool {
+	return ev.Label(0).Key() == keys.Msg &&
+		ev.Label(1).Key() == keys.Err
+}
+
+// Metric sends a label event to the exporter with the supplied labels.
+func Metric(ctx context.Context, labels ...label.Label) {
+	core.Export(ctx, core.MakeEvent([3]label.Label{
+		keys.Metric.New(),
+	}, labels))
+}
+
+// IsMetric returns true if the event was built by the Metric function.
+// It is intended to be used in exporters to identify the semantics of the
+// event when deciding what to do with it.
+func IsMetric(ev core.Event) bool {
+	return ev.Label(0).Key() == keys.Metric
+}
+
+// Label sends a label event to the exporter with the supplied labels.
+func Label(ctx context.Context, labels ...label.Label) context.Context {
+	return core.Export(ctx, core.MakeEvent([3]label.Label{
+		keys.Label.New(),
+	}, labels))
+}
+
+// IsLabel returns true if the event was built by the Label function.
+// It is intended to be used in exporters to identify the semantics of the
+// event when deciding what to do with it.
+func IsLabel(ev core.Event) bool {
+	return ev.Label(0).Key() == keys.Label
+}
+
+// Start sends a span start event with the supplied label list to the exporter.
+// It also returns a function that will end the span, which should normally be
+// deferred.
+func Start(ctx context.Context, name string, labels ...label.Label) (context.Context, func()) {
+	return core.ExportPair(ctx,
+		core.MakeEvent([3]label.Label{
+			keys.Start.Of(name),
+		}, labels),
+		core.MakeEvent([3]label.Label{
+			keys.End.New(),
+		}, nil))
+}
+
+// IsStart returns true if the event was built by the Start function.
+// It is intended to be used in exporters to identify the semantics of the
+// event when deciding what to do with it.
+func IsStart(ev core.Event) bool {
+	return ev.Label(0).Key() == keys.Start
+}
+
+// IsEnd returns true if the event was built by the End function.
+// It is intended to be used in exporters to identify the semantics of the
+// event when deciding what to do with it.
+func IsEnd(ev core.Event) bool {
+	return ev.Label(0).Key() == keys.End
+}
+
+// Detach returns a context without an associated span.
+// This allows the creation of spans that are not children of the current span.
+func Detach(ctx context.Context) context.Context {
+	return core.Export(ctx, core.MakeEvent([3]label.Label{
+		keys.Detach.New(),
+	}, nil))
+}
+
+// IsDetach returns true if the event was built by the Detach function.
+// It is intended to be used in exporters to identify the semantics of the
+// event when deciding what to do with it.
+func IsDetach(ev core.Event) bool {
+	return ev.Label(0).Key() == keys.Detach
+}

vendor/golang.org/x/tools/internal/event/keys/keys.go

@@ -0,0 +1,564 @@
+// Copyright 2019 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package keys
+
+import (
+	"fmt"
+	"io"
+	"math"
+	"strconv"
+
+	"golang.org/x/tools/internal/event/label"
+)
+
+// Value represents a key for untyped values.
+type Value struct {
+	name        string
+	description string
+}
+
+// New creates a new Key for untyped values.
+func New(name, description string) *Value {
+	return &Value{name: name, description: description}
+}
+
+func (k *Value) Name() string        { return k.name }
+func (k *Value) Description() string { return k.description }
+
+func (k *Value) Format(w io.Writer, buf []byte, l label.Label) {
+	fmt.Fprint(w, k.From(l))
+}
+
+// Get can be used to get a label for the key from a label.Map.
+func (k *Value) Get(lm label.Map) interface{} {
+	if t := lm.Find(k); t.Valid() {
+		return k.From(t)
+	}
+	return nil
+}
+
+// From can be used to get a value from a Label.
+func (k *Value) From(t label.Label) interface{} { return t.UnpackValue() }
+
+// Of creates a new Label with this key and the supplied value.
+func (k *Value) Of(value interface{}) label.Label { return label.OfValue(k, value) }
+
+// Tag represents a key for tagging labels that have no value.
+// These are used when the existence of the label is the entire information it
+// carries, such as marking events to be of a specific kind, or from a specific
+// package.
+type Tag struct {
+	name        string
+	description string
+}
+
+// NewTag creates a new Key for tagging labels.
+func NewTag(name, description string) *Tag {
+	return &Tag{name: name, description: description}
+}
+
+func (k *Tag) Name() string        { return k.name }
+func (k *Tag) Description() string { return k.description }
+
+func (k *Tag) Format(w io.Writer, buf []byte, l label.Label) {}
+
+// New creates a new Label with this key.
+func (k *Tag) New() label.Label { return label.OfValue(k, nil) }
+
+// Int represents a key
+type Int struct {
+	name        string
+	description string
+}
+
+// NewInt creates a new Key for int values.
+func NewInt(name, description string) *Int {
+	return &Int{name: name, description: description}
+}
+
+func (k *Int) Name() string        { return k.name }
+func (k *Int) Description() string { return k.description }
+
+func (k *Int) Format(w io.Writer, buf []byte, l label.Label) {
+	w.Write(strconv.AppendInt(buf, int64(k.From(l)), 10))
+}
+
+// Of creates a new Label with this key and the supplied value.
+func (k *Int) Of(v int) label.Label { return label.Of64(k, uint64(v)) }
+
+// Get can be used to get a label for the key from a label.Map.
+func (k *Int) Get(lm label.Map) int {
+	if t := lm.Find(k); t.Valid() {
+		return k.From(t)
+	}
+	return 0
+}
+
+// From can be used to get a value from a Label.
+func (k *Int) From(t label.Label) int { return int(t.Unpack64()) }
+
+// Int8 represents a key
+type Int8 struct {
+	name        string
+	description string
+}
+
+// NewInt8 creates a new Key for int8 values.
+func NewInt8(name, description string) *Int8 {
+	return &Int8{name: name, description: description}
+}
+
+func (k *Int8) Name() string        { return k.name }
+func (k *Int8) Description() string { return k.description }
+
+func (k *Int8) Format(w io.Writer, buf []byte, l label.Label) {
+	w.Write(strconv.AppendInt(buf, int64(k.From(l)), 10))
+}
+
+// Of creates a new Label with this key and the supplied value.
+func (k *Int8) Of(v int8) label.Label { return label.Of64(k, uint64(v)) }
+
+// Get can be used to get a label for the key from a label.Map.
+func (k *Int8) Get(lm label.Map) int8 {
+	if t := lm.Find(k); t.Valid() {
+		return k.From(t)
+	}
+	return 0
+}
+
+// From can be used to get a value from a Label.
+func (k *Int8) From(t label.Label) int8 { return int8(t.Unpack64()) }
+
+// Int16 represents a key
+type Int16 struct {
+	name        string
+	description string
+}
+
+// NewInt16 creates a new Key for int16 values.
+func NewInt16(name, description string) *Int16 {
+	return &Int16{name: name, description: description}
+}
+
+func (k *Int16) Name() string        { return k.name }
+func (k *Int16) Description() string { return k.description }
+
+func (k *Int16) Format(w io.Writer, buf []byte, l label.Label) {
+	w.Write(strconv.AppendInt(buf, int64(k.From(l)), 10))
+}
+
+// Of creates a new Label with this key and the supplied value.
+func (k *Int16) Of(v int16) label.Label { return label.Of64(k, uint64(v)) }
+
+// Get can be used to get a label for the key from a label.Map.
+func (k *Int16) Get(lm label.Map) int16 {
+	if t := lm.Find(k); t.Valid() {
+		return k.From(t)
+	}
+	return 0
+}
+
+// From can be used to get a value from a Label.
+func (k *Int16) From(t label.Label) int16 { return int16(t.Unpack64()) }
+
+// Int32 represents a key
+type Int32 struct {
+	name        string
+	description string
+}
+
+// NewInt32 creates a new Key for int32 values.
+func NewInt32(name, description string) *Int32 {
+	return &Int32{name: name, description: description}
+}
+
+func (k *Int32) Name() string        { return k.name }
+func (k *Int32) Description() string { return k.description }
+
+func (k *Int32) Format(w io.Writer, buf []byte, l label.Label) {
+	w.Write(strconv.AppendInt(buf, int64(k.From(l)), 10))
+}
+
+// Of creates a new Label with this key and the supplied value.
+func (k *Int32) Of(v int32) label.Label { return label.Of64(k, uint64(v)) }
+
+// Get can be used to get a label for the key from a label.Map.
+func (k *Int32) Get(lm label.Map) int32 {
+	if t := lm.Find(k); t.Valid() {
+		return k.From(t)
+	}
+	return 0
+}
+
+// From can be used to get a value from a Label.
+func (k *Int32) From(t label.Label) int32 { return int32(t.Unpack64()) }
+
+// Int64 represents a key
+type Int64 struct {
+	name        string
+	description string
+}
+
+// NewInt64 creates a new Key for int64 values.
+func NewInt64(name, description string) *Int64 {
+	return &Int64{name: name, description: description}
+}
+
+func (k *Int64) Name() string        { return k.name }
+func (k *Int64) Description() string { return k.description }
+
+func (k *Int64) Format(w io.Writer, buf []byte, l label.Label) {
+	w.Write(strconv.AppendInt(buf, k.From(l), 10))
+}
+
+// Of creates a new Label with this key and the supplied value.
+func (k *Int64) Of(v int64) label.Label { return label.Of64(k, uint64(v)) }
+
+// Get can be used to get a label for the key from a label.Map.
+func (k *Int64) Get(lm label.Map) int64 {
+	if t := lm.Find(k); t.Valid() {
+		return k.From(t)
+	}
+	return 0
+}
+
+// From can be used to get a value from a Label.
+func (k *Int64) From(t label.Label) int64 { return int64(t.Unpack64()) }
+
+// UInt represents a key
+type UInt struct {
+	name        string
+	description string
+}
+
+// NewUInt creates a new Key for uint values.
+func NewUInt(name, description string) *UInt {
+	return &UInt{name: name, description: description}
+}
+
+func (k *UInt) Name() string        { return k.name }
+func (k *UInt) Description() string { return k.description }
+
+func (k *UInt) Format(w io.Writer, buf []byte, l label.Label) {
+	w.Write(strconv.AppendUint(buf, uint64(k.From(l)), 10))
+}
+
+// Of creates a new Label with this key and the supplied value.
+func (k *UInt) Of(v uint) label.Label { return label.Of64(k, uint64(v)) }
+
+// Get can be used to get a label for the key from a label.Map.
+func (k *UInt) Get(lm label.Map) uint {
+	if t := lm.Find(k); t.Valid() {
+		return k.From(t)
+	}
+	return 0
+}
+
+// From can be used to get a value from a Label.
+func (k *UInt) From(t label.Label) uint { return uint(t.Unpack64()) }
+
+// UInt8 represents a key
+type UInt8 struct {
+	name        string
+	description string
+}
+
+// NewUInt8 creates a new Key for uint8 values.
+func NewUInt8(name, description string) *UInt8 {
+	return &UInt8{name: name, description: description}
+}
+
+func (k *UInt8) Name() string        { return k.name }
+func (k *UInt8) Description() string { return k.description }
+
+func (k *UInt8) Format(w io.Writer, buf []byte, l label.Label) {
+	w.Write(strconv.AppendUint(buf, uint64(k.From(l)), 10))
+}
+
+// Of creates a new Label with this key and the supplied value.
+func (k *UInt8) Of(v uint8) label.Label { return label.Of64(k, uint64(v)) }
+
+// Get can be used to get a label for the key from a label.Map.
+func (k *UInt8) Get(lm label.Map) uint8 {
+	if t := lm.Find(k); t.Valid() {
+		return k.From(t)
+	}
+	return 0
+}
+
+// From can be used to get a value from a Label.
+func (k *UInt8) From(t label.Label) uint8 { return uint8(t.Unpack64()) }
+
+// UInt16 represents a key
+type UInt16 struct {
+	name        string
+	description string
+}
+
+// NewUInt16 creates a new Key for uint16 values.
+func NewUInt16(name, description string) *UInt16 {
+	return &UInt16{name: name, description: description}
+}
+
+func (k *UInt16) Name() string        { return k.name }
+func (k *UInt16) Description() string { return k.description }
+
+func (k *UInt16) Format(w io.Writer, buf []byte, l label.Label) {
+	w.Write(strconv.AppendUint(buf, uint64(k.From(l)), 10))
+}
+
+// Of creates a new Label with this key and the supplied value.
+func (k *UInt16) Of(v uint16) label.Label { return label.Of64(k, uint64(v)) }
+
+// Get can be used to get a label for the key from a label.Map.
+func (k *UInt16) Get(lm label.Map) uint16 {
+	if t := lm.Find(k); t.Valid() {
+		return k.From(t)
+	}
+	return 0
+}
+
+// From can be used to get a value from a Label.
+func (k *UInt16) From(t label.Label) uint16 { return uint16(t.Unpack64()) }
+
+// UInt32 represents a key
+type UInt32 struct {
+	name        string
+	description string
+}
+
+// NewUInt32 creates a new Key for uint32 values.
+func NewUInt32(name, description string) *UInt32 {
+	return &UInt32{name: name, description: description}
+}
+
+func (k *UInt32) Name() string        { return k.name }
+func (k *UInt32) Description() string { return k.description }
+
+func (k *UInt32) Format(w io.Writer, buf []byte, l label.Label) {
+	w.Write(strconv.AppendUint(buf, uint64(k.From(l)), 10))
+}
+
+// Of creates a new Label with this key and the supplied value.
+func (k *UInt32) Of(v uint32) label.Label { return label.Of64(k, uint64(v)) }
+
+// Get can be used to get a label for the key from a label.Map.
+func (k *UInt32) Get(lm label.Map) uint32 {
+	if t := lm.Find(k); t.Valid() {
+		return k.From(t)
+	}
+	return 0
+}
+
+// From can be used to get a value from a Label.
+func (k *UInt32) From(t label.Label) uint32 { return uint32(t.Unpack64()) }
+
+// UInt64 represents a key
+type UInt64 struct {
+	name        string
+	description string
+}
+
+// NewUInt64 creates a new Key for uint64 values.
+func NewUInt64(name, description string) *UInt64 {
+	return &UInt64{name: name, description: description}
+}
+
+func (k *UInt64) Name() string        { return k.name }
+func (k *UInt64) Description() string { return k.description }
+
+func (k *UInt64) Format(w io.Writer, buf []byte, l label.Label) {
+	w.Write(strconv.AppendUint(buf, k.From(l), 10))
+}
+
+// Of creates a new Label with this key and the supplied value.
+func (k *UInt64) Of(v uint64) label.Label { return label.Of64(k, v) }
+
+// Get can be used to get a label for the key from a label.Map.
+func (k *UInt64) Get(lm label.Map) uint64 {
+	if t := lm.Find(k); t.Valid() {
+		return k.From(t)
+	}
+	return 0
+}
+
+// From can be used to get a value from a Label.
+func (k *UInt64) From(t label.Label) uint64 { return t.Unpack64() }
+
+// Float32 represents a key
+type Float32 struct {
+	name        string
+	description string
+}
+
+// NewFloat32 creates a new Key for float32 values.
+func NewFloat32(name, description string) *Float32 {
+	return &Float32{name: name, description: description}
+}
+
+func (k *Float32) Name() string        { return k.name }
+func (k *Float32) Description() string { return k.description }
+
+func (k *Float32) Format(w io.Writer, buf []byte, l label.Label) {
+	w.Write(strconv.AppendFloat(buf, float64(k.From(l)), 'E', -1, 32))
+}
+
+// Of creates a new Label with this key and the supplied value.
+func (k *Float32) Of(v float32) label.Label {
+	return label.Of64(k, uint64(math.Float32bits(v)))
+}
+
+// Get can be used to get a label for the key from a label.Map.
+func (k *Float32) Get(lm label.Map) float32 {
+	if t := lm.Find(k); t.Valid() {
+		return k.From(t)
+	}
+	return 0
+}
+
+// From can be used to get a value from a Label.
+func (k *Float32) From(t label.Label) float32 {
+	return math.Float32frombits(uint32(t.Unpack64()))
+}
+
+// Float64 represents a key
+type Float64 struct {
+	name        string
+	description string
+}
+
+// NewFloat64 creates a new Key for int64 values.
+func NewFloat64(name, description string) *Float64 {
+	return &Float64{name: name, description: description}
+}
+
+func (k *Float64) Name() string        { return k.name }
+func (k *Float64) Description() string { return k.description }
+
+func (k *Float64) Format(w io.Writer, buf []byte, l label.Label) {
+	w.Write(strconv.AppendFloat(buf, k.From(l), 'E', -1, 64))
+}
+
+// Of creates a new Label with this key and the supplied value.
+func (k *Float64) Of(v float64) label.Label {
+	return label.Of64(k, math.Float64bits(v))
+}
+
+// Get can be used to get a label for the key from a label.Map.
+func (k *Float64) Get(lm label.Map) float64 {
+	if t := lm.Find(k); t.Valid() {
+		return k.From(t)
+	}
+	return 0
+}
+
+// From can be used to get a value from a Label.
+func (k *Float64) From(t label.Label) float64 {
+	return math.Float64frombits(t.Unpack64())
+}
+
+// String represents a key
+type String struct {
+	name        string
+	description string
+}
+
+// NewString creates a new Key for int64 values.
+func NewString(name, description string) *String {
+	return &String{name: name, description: description}
+}
+
+func (k *String) Name() string        { return k.name }
+func (k *String) Description() string { return k.description }
+
+func (k *String) Format(w io.Writer, buf []byte, l label.Label) {
+	w.Write(strconv.AppendQuote(buf, k.From(l)))
+}
+
+// Of creates a new Label with this key and the supplied value.
+func (k *String) Of(v string) label.Label { return label.OfString(k, v) }
+
+// Get can be used to get a label for the key from a label.Map.
+func (k *String) Get(lm label.Map) string {
+	if t := lm.Find(k); t.Valid() {
+		return k.From(t)
+	}
+	return ""
+}
+
+// From can be used to get a value from a Label.
+func (k *String) From(t label.Label) string { return t.UnpackString() }
+
+// Boolean represents a key
+type Boolean struct {
+	name        string
+	description string
+}
+
+// NewBoolean creates a new Key for bool values.
+func NewBoolean(name, description string) *Boolean {
+	return &Boolean{name: name, description: description}
+}
+
+func (k *Boolean) Name() string        { return k.name }
+func (k *Boolean) Description() string { return k.description }
+
+func (k *Boolean) Format(w io.Writer, buf []byte, l label.Label) {
+	w.Write(strconv.AppendBool(buf, k.From(l)))
+}
+
+// Of creates a new Label with this key and the supplied value.
+func (k *Boolean) Of(v bool) label.Label {
+	if v {
+		return label.Of64(k, 1)
+	}
+	return label.Of64(k, 0)
+}
+
+// Get can be used to get a label for the key from a label.Map.
+func (k *Boolean) Get(lm label.Map) bool {
+	if t := lm.Find(k); t.Valid() {
+		return k.From(t)
+	}
+	return false
+}
+
+// From can be used to get a value from a Label.
+func (k *Boolean) From(t label.Label) bool { return t.Unpack64() > 0 }
+
+// Error represents a key
+type Error struct {
+	name        string
+	description string
+}
+
+// NewError creates a new Key for int64 values.
+func NewError(name, description string) *Error {
+	return &Error{name: name, description: description}
+}
+
+func (k *Error) Name() string        { return k.name }
+func (k *Error) Description() string { return k.description }
+
+func (k *Error) Format(w io.Writer, buf []byte, l label.Label) {
+	io.WriteString(w, k.From(l).Error())
+}
+
+// Of creates a new Label with this key and the supplied value.
+func (k *Error) Of(v error) label.Label { return label.OfValue(k, v) }
+
+// Get can be used to get a label for the key from a label.Map.
+func (k *Error) Get(lm label.Map) error {
+	if t := lm.Find(k); t.Valid() {
+		return k.From(t)
+	}
+	return nil
+}
+
+// From can be used to get a value from a Label.
+func (k *Error) From(t label.Label) error {
+	err, _ := t.UnpackValue().(error)
+	return err
+}

vendor/golang.org/x/tools/internal/event/keys/standard.go

@@ -0,0 +1,22 @@
+// Copyright 2020 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package keys
+
+var (
+	// Msg is a key used to add message strings to label lists.
+	Msg = NewString("message", "a readable message")
+	// Label is a key used to indicate an event adds labels to the context.
+	Label = NewTag("label", "a label context marker")
+	// Start is used for things like traces that have a name.
+	Start = NewString("start", "span start")
+	// Metric is a key used to indicate an event records metrics.
+	End = NewTag("end", "a span end marker")
+	// Metric is a key used to indicate an event records metrics.
+	Detach = NewTag("detach", "a span detach marker")
+	// Err is a key used to add error values to label lists.
+	Err = NewError("error", "an error that occurred")
+	// Metric is a key used to indicate an event records metrics.
+	Metric = NewTag("metric", "a metric event marker")
+)

vendor/golang.org/x/tools/internal/event/label/label.go

@@ -0,0 +1,213 @@
+// Copyright 2019 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package label
+
+import (
+	"fmt"
+	"io"
+	"reflect"
+	"unsafe"
+)
+
+// Key is used as the identity of a Label.
+// Keys are intended to be compared by pointer only, the name should be unique
+// for communicating with external systems, but it is not required or enforced.
+type Key interface {
+	// Name returns the key name.
+	Name() string
+	// Description returns a string that can be used to describe the value.
+	Description() string
+
+	// Format is used in formatting to append the value of the label to the
+	// supplied buffer.
+	// The formatter may use the supplied buf as a scratch area to avoid
+	// allocations.
+	Format(w io.Writer, buf []byte, l Label)
+}
+
+// Label holds a key and value pair.
+// It is normally used when passing around lists of labels.
+type Label struct {
+	key     Key
+	packed  uint64
+	untyped interface{}
+}
+
+// Map is the interface to a collection of Labels indexed by key.
+type Map interface {
+	// Find returns the label that matches the supplied key.
+	Find(key Key) Label
+}
+
+// List is the interface to something that provides an iterable
+// list of labels.
+// Iteration should start from 0 and continue until Valid returns false.
+type List interface {
+	// Valid returns true if the index is within range for the list.
+	// It does not imply the label at that index will itself be valid.
+	Valid(index int) bool
+	// Label returns the label at the given index.
+	Label(index int) Label
+}
+
+// list implements LabelList for a list of Labels.
+type list struct {
+	labels []Label
+}
+
+// filter wraps a LabelList filtering out specific labels.
+type filter struct {
+	keys       []Key
+	underlying List
+}
+
+// listMap implements LabelMap for a simple list of labels.
+type listMap struct {
+	labels []Label
+}
+
+// mapChain implements LabelMap for a list of underlying LabelMap.
+type mapChain struct {
+	maps []Map
+}
+
+// OfValue creates a new label from the key and value.
+// This method is for implementing new key types, label creation should
+// normally be done with the Of method of the key.
+func OfValue(k Key, value interface{}) Label { return Label{key: k, untyped: value} }
+
+// UnpackValue assumes the label was built using LabelOfValue and returns the value
+// that was passed to that constructor.
+// This method is for implementing new key types, for type safety normal
+// access should be done with the From method of the key.
+func (t Label) UnpackValue() interface{} { return t.untyped }
+
+// Of64 creates a new label from a key and a uint64. This is often
+// used for non uint64 values that can be packed into a uint64.
+// This method is for implementing new key types, label creation should
+// normally be done with the Of method of the key.
+func Of64(k Key, v uint64) Label { return Label{key: k, packed: v} }
+
+// Unpack64 assumes the label was built using LabelOf64 and returns the value that
+// was passed to that constructor.
+// This method is for implementing new key types, for type safety normal
+// access should be done with the From method of the key.
+func (t Label) Unpack64() uint64 { return t.packed }
+
+// OfString creates a new label from a key and a string.
+// This method is for implementing new key types, label creation should
+// normally be done with the Of method of the key.
+func OfString(k Key, v string) Label {
+	hdr := (*reflect.StringHeader)(unsafe.Pointer(&v))
+	return Label{
+		key:     k,
+		packed:  uint64(hdr.Len),
+		untyped: unsafe.Pointer(hdr.Data),
+	}
+}
+
+// UnpackString assumes the label was built using LabelOfString and returns the
+// value that was passed to that constructor.
+// This method is for implementing new key types, for type safety normal
+// access should be done with the From method of the key.
+func (t Label) UnpackString() string {
+	var v string
+	hdr := (*reflect.StringHeader)(unsafe.Pointer(&v))
+	hdr.Data = uintptr(t.untyped.(unsafe.Pointer))
+	hdr.Len = int(t.packed)
+	return *(*string)(unsafe.Pointer(hdr))
+}
+
+// Valid returns true if the Label is a valid one (it has a key).
+func (t Label) Valid() bool { return t.key != nil }
+
+// Key returns the key of this Label.
+func (t Label) Key() Key { return t.key }
+
+// Format is used for debug printing of labels.
+func (t Label) Format(f fmt.State, r rune) {
+	if !t.Valid() {
+		io.WriteString(f, `nil`)
+		return
+	}
+	io.WriteString(f, t.Key().Name())
+	io.WriteString(f, "=")
+	var buf [128]byte
+	t.Key().Format(f, buf[:0], t)
+}
+
+func (l *list) Valid(index int) bool {
+	return index >= 0 && index < len(l.labels)
+}
+
+func (l *list) Label(index int) Label {
+	return l.labels[index]
+}
+
+func (f *filter) Valid(index int) bool {
+	return f.underlying.Valid(index)
+}
+
+func (f *filter) Label(index int) Label {
+	l := f.underlying.Label(index)
+	for _, f := range f.keys {
+		if l.Key() == f {
+			return Label{}
+		}
+	}
+	return l
+}
+
+func (lm listMap) Find(key Key) Label {
+	for _, l := range lm.labels {
+		if l.Key() == key {
+			return l
+		}
+	}
+	return Label{}
+}
+
+func (c mapChain) Find(key Key) Label {
+	for _, src := range c.maps {
+		l := src.Find(key)
+		if l.Valid() {
+			return l
+		}
+	}
+	return Label{}
+}
+
+var emptyList = &list{}
+
+func NewList(labels ...Label) List {
+	if len(labels) == 0 {
+		return emptyList
+	}
+	return &list{labels: labels}
+}
+
+func Filter(l List, keys ...Key) List {
+	if len(keys) == 0 {
+		return l
+	}
+	return &filter{keys: keys, underlying: l}
+}
+
+func NewMap(labels ...Label) Map {
+	return listMap{labels: labels}
+}
+
+func MergeMaps(srcs ...Map) Map {
+	var nonNil []Map
+	for _, src := range srcs {
+		if src != nil {
+			nonNil = append(nonNil, src)
+		}
+	}
+	if len(nonNil) == 1 {
+		return nonNil[0]
+	}
+	return mapChain{maps: nonNil}
+}

vendor/golang.org/x/tools/internal/fastwalk/fastwalk.go

@@ -14,14 +14,14 @@ import (
 	"sync"
 )
 
-// TraverseLink is used as a return value from WalkFuncs to indicate that the
+// ErrTraverseLink is used as a return value from WalkFuncs to indicate that the
 // symlink named in the call may be traversed.
-var TraverseLink = errors.New("fastwalk: traverse symlink, assuming target is a directory")
+var ErrTraverseLink = errors.New("fastwalk: traverse symlink, assuming target is a directory")
 
-// SkipFiles is a used as a return value from WalkFuncs to indicate that the
+// ErrSkipFiles is a used as a return value from WalkFuncs to indicate that the
 // callback should not be called for any other files in the current directory.
 // Child directories will still be traversed.
-var SkipFiles = errors.New("fastwalk: skip remaining files in directory")
+var ErrSkipFiles = errors.New("fastwalk: skip remaining files in directory")
 
 // Walk is a faster implementation of filepath.Walk.
 //
@@ -167,7 +167,7 @@ func (w *walker) onDirEnt(dirName, baseName string, typ os.FileMode) error {
 
 	err := w.fn(joined, typ)
 	if typ == os.ModeSymlink {
-		if err == TraverseLink {
+		if err == ErrTraverseLink {
 			// Set callbackDone so we don't call it twice for both the
 			// symlink-as-symlink and the symlink-as-directory later:
 			w.enqueue(walkItem{dir: joined, callbackDone: true})

vendor/golang.org/x/tools/internal/fastwalk/fastwalk_portable.go

@@ -26,7 +26,7 @@ func readDir(dirName string, fn func(dirName, entName string, typ os.FileMode) e
 			continue
 		}
 		if err := fn(dirName, fi.Name(), fi.Mode()&os.ModeType); err != nil {
-			if err == SkipFiles {
+			if err == ErrSkipFiles {
 				skipFiles = true
 				continue
 			}

vendor/golang.org/x/tools/internal/fastwalk/fastwalk_unix.go

@@ -66,7 +66,7 @@ func readDir(dirName string, fn func(dirName, entName string, typ os.FileMode) e
 			continue
 		}
 		if err := fn(dirName, name, typ); err != nil {
-			if err == SkipFiles {
+			if err == ErrSkipFiles {
 				skipFiles = true
 				continue
 			}
@@ -76,8 +76,9 @@ func readDir(dirName string, fn func(dirName, entName string, typ os.FileMode) e
 }
 
 func parseDirEnt(buf []byte) (consumed int, name string, typ os.FileMode) {
-	// golang.org/issue/15653
-	dirent := (*syscall.Dirent)(unsafe.Pointer(&buf[0]))
+	// golang.org/issue/37269
+	dirent := &syscall.Dirent{}
+	copy((*[unsafe.Sizeof(syscall.Dirent{})]byte)(unsafe.Pointer(dirent))[:], buf)
 	if v := unsafe.Offsetof(dirent.Reclen) + unsafe.Sizeof(dirent.Reclen); uintptr(len(buf)) < v {
 		panic(fmt.Sprintf("buf size of %d smaller than dirent header size %d", len(buf), v))
 	}

vendor/golang.org/x/tools/internal/gocommand/invoke.go

@@ -0,0 +1,273 @@
+// Copyright 2020 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Package gocommand is a helper for calling the go command.
+package gocommand
+
+import (
+	"bytes"
+	"context"
+	"fmt"
+	exec "golang.org/x/sys/execabs"
+	"io"
+	"os"
+	"regexp"
+	"strconv"
+	"strings"
+	"sync"
+	"time"
+
+	"golang.org/x/tools/internal/event"
+)
+
+// An Runner will run go command invocations and serialize
+// them if it sees a concurrency error.
+type Runner struct {
+	// once guards the runner initialization.
+	once sync.Once
+
+	// inFlight tracks available workers.
+	inFlight chan struct{}
+
+	// serialized guards the ability to run a go command serially,
+	// to avoid deadlocks when claiming workers.
+	serialized chan struct{}
+}
+
+const maxInFlight = 10
+
+func (runner *Runner) initialize() {
+	runner.once.Do(func() {
+		runner.inFlight = make(chan struct{}, maxInFlight)
+		runner.serialized = make(chan struct{}, 1)
+	})
+}
+
+// 1.13: go: updates to go.mod needed, but contents have changed
+// 1.14: go: updating go.mod: existing contents have changed since last read
+var modConcurrencyError = regexp.MustCompile(`go:.*go.mod.*contents have changed`)
+
+// Run is a convenience wrapper around RunRaw.
+// It returns only stdout and a "friendly" error.
+func (runner *Runner) Run(ctx context.Context, inv Invocation) (*bytes.Buffer, error) {
+	stdout, _, friendly, _ := runner.RunRaw(ctx, inv)
+	return stdout, friendly
+}
+
+// RunPiped runs the invocation serially, always waiting for any concurrent
+// invocations to complete first.
+func (runner *Runner) RunPiped(ctx context.Context, inv Invocation, stdout, stderr io.Writer) error {
+	_, err := runner.runPiped(ctx, inv, stdout, stderr)
+	return err
+}
+
+// RunRaw runs the invocation, serializing requests only if they fight over
+// go.mod changes.
+func (runner *Runner) RunRaw(ctx context.Context, inv Invocation) (*bytes.Buffer, *bytes.Buffer, error, error) {
+	// Make sure the runner is always initialized.
+	runner.initialize()
+
+	// First, try to run the go command concurrently.
+	stdout, stderr, friendlyErr, err := runner.runConcurrent(ctx, inv)
+
+	// If we encounter a load concurrency error, we need to retry serially.
+	if friendlyErr == nil || !modConcurrencyError.MatchString(friendlyErr.Error()) {
+		return stdout, stderr, friendlyErr, err
+	}
+	event.Error(ctx, "Load concurrency error, will retry serially", err)
+
+	// Run serially by calling runPiped.
+	stdout.Reset()
+	stderr.Reset()
+	friendlyErr, err = runner.runPiped(ctx, inv, stdout, stderr)
+	return stdout, stderr, friendlyErr, err
+}
+
+func (runner *Runner) runConcurrent(ctx context.Context, inv Invocation) (*bytes.Buffer, *bytes.Buffer, error, error) {
+	// Wait for 1 worker to become available.
+	select {
+	case <-ctx.Done():
+		return nil, nil, nil, ctx.Err()
+	case runner.inFlight <- struct{}{}:
+		defer func() { <-runner.inFlight }()
+	}
+
+	stdout, stderr := &bytes.Buffer{}, &bytes.Buffer{}
+	friendlyErr, err := inv.runWithFriendlyError(ctx, stdout, stderr)
+	return stdout, stderr, friendlyErr, err
+}
+
+func (runner *Runner) runPiped(ctx context.Context, inv Invocation, stdout, stderr io.Writer) (error, error) {
+	// Make sure the runner is always initialized.
+	runner.initialize()
+
+	// Acquire the serialization lock. This avoids deadlocks between two
+	// runPiped commands.
+	select {
+	case <-ctx.Done():
+		return nil, ctx.Err()
+	case runner.serialized <- struct{}{}:
+		defer func() { <-runner.serialized }()
+	}
+
+	// Wait for all in-progress go commands to return before proceeding,
+	// to avoid load concurrency errors.
+	for i := 0; i < maxInFlight; i++ {
+		select {
+		case <-ctx.Done():
+			return nil, ctx.Err()
+		case runner.inFlight <- struct{}{}:
+			// Make sure we always "return" any workers we took.
+			defer func() { <-runner.inFlight }()
+		}
+	}
+
+	return inv.runWithFriendlyError(ctx, stdout, stderr)
+}
+
+// An Invocation represents a call to the go command.
+type Invocation struct {
+	Verb       string
+	Args       []string
+	BuildFlags []string
+	ModFlag    string
+	ModFile    string
+	Overlay    string
+	// If CleanEnv is set, the invocation will run only with the environment
+	// in Env, not starting with os.Environ.
+	CleanEnv   bool
+	Env        []string
+	WorkingDir string
+	Logf       func(format string, args ...interface{})
+}
+
+func (i *Invocation) runWithFriendlyError(ctx context.Context, stdout, stderr io.Writer) (friendlyError error, rawError error) {
+	rawError = i.run(ctx, stdout, stderr)
+	if rawError != nil {
+		friendlyError = rawError
+		// Check for 'go' executable not being found.
+		if ee, ok := rawError.(*exec.Error); ok && ee.Err == exec.ErrNotFound {
+			friendlyError = fmt.Errorf("go command required, not found: %v", ee)
+		}
+		if ctx.Err() != nil {
+			friendlyError = ctx.Err()
+		}
+		friendlyError = fmt.Errorf("err: %v: stderr: %s", friendlyError, stderr)
+	}
+	return
+}
+
+func (i *Invocation) run(ctx context.Context, stdout, stderr io.Writer) error {
+	log := i.Logf
+	if log == nil {
+		log = func(string, ...interface{}) {}
+	}
+
+	goArgs := []string{i.Verb}
+
+	appendModFile := func() {
+		if i.ModFile != "" {
+			goArgs = append(goArgs, "-modfile="+i.ModFile)
+		}
+	}
+	appendModFlag := func() {
+		if i.ModFlag != "" {
+			goArgs = append(goArgs, "-mod="+i.ModFlag)
+		}
+	}
+	appendOverlayFlag := func() {
+		if i.Overlay != "" {
+			goArgs = append(goArgs, "-overlay="+i.Overlay)
+		}
+	}
+
+	switch i.Verb {
+	case "env", "version":
+		goArgs = append(goArgs, i.Args...)
+	case "mod":
+		// mod needs the sub-verb before flags.
+		goArgs = append(goArgs, i.Args[0])
+		appendModFile()
+		goArgs = append(goArgs, i.Args[1:]...)
+	case "get":
+		goArgs = append(goArgs, i.BuildFlags...)
+		appendModFile()
+		goArgs = append(goArgs, i.Args...)
+
+	default: // notably list and build.
+		goArgs = append(goArgs, i.BuildFlags...)
+		appendModFile()
+		appendModFlag()
+		appendOverlayFlag()
+		goArgs = append(goArgs, i.Args...)
+	}
+	cmd := exec.Command("go", goArgs...)
+	cmd.Stdout = stdout
+	cmd.Stderr = stderr
+	// On darwin the cwd gets resolved to the real path, which breaks anything that
+	// expects the working directory to keep the original path, including the
+	// go command when dealing with modules.
+	// The Go stdlib has a special feature where if the cwd and the PWD are the
+	// same node then it trusts the PWD, so by setting it in the env for the child
+	// process we fix up all the paths returned by the go command.
+	if !i.CleanEnv {
+		cmd.Env = os.Environ()
+	}
+	cmd.Env = append(cmd.Env, i.Env...)
+	if i.WorkingDir != "" {
+		cmd.Env = append(cmd.Env, "PWD="+i.WorkingDir)
+		cmd.Dir = i.WorkingDir
+	}
+	defer func(start time.Time) { log("%s for %v", time.Since(start), cmdDebugStr(cmd)) }(time.Now())
+
+	return runCmdContext(ctx, cmd)
+}
+
+// runCmdContext is like exec.CommandContext except it sends os.Interrupt
+// before os.Kill.
+func runCmdContext(ctx context.Context, cmd *exec.Cmd) error {
+	if err := cmd.Start(); err != nil {
+		return err
+	}
+	resChan := make(chan error, 1)
+	go func() {
+		resChan <- cmd.Wait()
+	}()
+
+	select {
+	case err := <-resChan:
+		return err
+	case <-ctx.Done():
+	}
+	// Cancelled. Interrupt and see if it ends voluntarily.
+	cmd.Process.Signal(os.Interrupt)
+	select {
+	case err := <-resChan:
+		return err
+	case <-time.After(time.Second):
+	}
+	// Didn't shut down in response to interrupt. Kill it hard.
+	cmd.Process.Kill()
+	return <-resChan
+}
+
+func cmdDebugStr(cmd *exec.Cmd) string {
+	env := make(map[string]string)
+	for _, kv := range cmd.Env {
+		split := strings.SplitN(kv, "=", 2)
+		k, v := split[0], split[1]
+		env[k] = v
+	}
+
+	var args []string
+	for _, arg := range cmd.Args {
+		quoted := strconv.Quote(arg)
+		if quoted[1:len(quoted)-1] != arg || strings.Contains(arg, " ") {
+			args = append(args, quoted)
+		} else {
+			args = append(args, arg)
+		}
+	}
+	return fmt.Sprintf("GOROOT=%v GOPATH=%v GO111MODULE=%v GOPROXY=%v PWD=%v %v", env["GOROOT"], env["GOPATH"], env["GO111MODULE"], env["GOPROXY"], env["PWD"], strings.Join(args, " "))
+}

vendor/golang.org/x/tools/internal/gocommand/vendor.go

@@ -0,0 +1,102 @@
+// Copyright 2020 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package gocommand
+
+import (
+	"bytes"
+	"context"
+	"fmt"
+	"os"
+	"path/filepath"
+	"regexp"
+	"strings"
+
+	"golang.org/x/mod/semver"
+)
+
+// ModuleJSON holds information about a module.
+type ModuleJSON struct {
+	Path      string      // module path
+	Replace   *ModuleJSON // replaced by this module
+	Main      bool        // is this the main module?
+	Indirect  bool        // is this module only an indirect dependency of main module?
+	Dir       string      // directory holding files for this module, if any
+	GoMod     string      // path to go.mod file for this module, if any
+	GoVersion string      // go version used in module
+}
+
+var modFlagRegexp = regexp.MustCompile(`-mod[ =](\w+)`)
+
+// VendorEnabled reports whether vendoring is enabled. It takes a *Runner to execute Go commands
+// with the supplied context.Context and Invocation. The Invocation can contain pre-defined fields,
+// of which only Verb and Args are modified to run the appropriate Go command.
+// Inspired by setDefaultBuildMod in modload/init.go
+func VendorEnabled(ctx context.Context, inv Invocation, r *Runner) (*ModuleJSON, bool, error) {
+	mainMod, go114, err := getMainModuleAnd114(ctx, inv, r)
+	if err != nil {
+		return nil, false, err
+	}
+
+	// We check the GOFLAGS to see if there is anything overridden or not.
+	inv.Verb = "env"
+	inv.Args = []string{"GOFLAGS"}
+	stdout, err := r.Run(ctx, inv)
+	if err != nil {
+		return nil, false, err
+	}
+	goflags := string(bytes.TrimSpace(stdout.Bytes()))
+	matches := modFlagRegexp.FindStringSubmatch(goflags)
+	var modFlag string
+	if len(matches) != 0 {
+		modFlag = matches[1]
+	}
+	if modFlag != "" {
+		// Don't override an explicit '-mod=' argument.
+		return mainMod, modFlag == "vendor", nil
+	}
+	if mainMod == nil || !go114 {
+		return mainMod, false, nil
+	}
+	// Check 1.14's automatic vendor mode.
+	if fi, err := os.Stat(filepath.Join(mainMod.Dir, "vendor")); err == nil && fi.IsDir() {
+		if mainMod.GoVersion != "" && semver.Compare("v"+mainMod.GoVersion, "v1.14") >= 0 {
+			// The Go version is at least 1.14, and a vendor directory exists.
+			// Set -mod=vendor by default.
+			return mainMod, true, nil
+		}
+	}
+	return mainMod, false, nil
+}
+
+// getMainModuleAnd114 gets the main module's information and whether the
+// go command in use is 1.14+. This is the information needed to figure out
+// if vendoring should be enabled.
+func getMainModuleAnd114(ctx context.Context, inv Invocation, r *Runner) (*ModuleJSON, bool, error) {
+	const format = `{{.Path}}
+{{.Dir}}
+{{.GoMod}}
+{{.GoVersion}}
+{{range context.ReleaseTags}}{{if eq . "go1.14"}}{{.}}{{end}}{{end}}
+`
+	inv.Verb = "list"
+	inv.Args = []string{"-m", "-f", format}
+	stdout, err := r.Run(ctx, inv)
+	if err != nil {
+		return nil, false, err
+	}
+
+	lines := strings.Split(stdout.String(), "\n")
+	if len(lines) < 5 {
+		return nil, false, fmt.Errorf("unexpected stdout: %q", stdout.String())
+	}
+	mod := &ModuleJSON{
+		Path:      lines[0],
+		Dir:       lines[1],
+		GoMod:     lines[2],
+		GoVersion: lines[3],
+		Main:      true,
+	}
+	return mod, lines[4] == "go1.14", nil
+}

vendor/golang.org/x/tools/internal/gocommand/version.go

@@ -0,0 +1,51 @@
+// Copyright 2020 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package gocommand
+
+import (
+	"context"
+	"fmt"
+	"strings"
+)
+
+// GoVersion checks the go version by running "go list" with modules off.
+// It returns the X in Go 1.X.
+func GoVersion(ctx context.Context, inv Invocation, r *Runner) (int, error) {
+	inv.Verb = "list"
+	inv.Args = []string{"-e", "-f", `{{context.ReleaseTags}}`}
+	inv.Env = append(append([]string{}, inv.Env...), "GO111MODULE=off")
+	// Unset any unneeded flags, and remove them from BuildFlags, if they're
+	// present.
+	inv.ModFile = ""
+	inv.ModFlag = ""
+	var buildFlags []string
+	for _, flag := range inv.BuildFlags {
+		// Flags can be prefixed by one or two dashes.
+		f := strings.TrimPrefix(strings.TrimPrefix(flag, "-"), "-")
+		if strings.HasPrefix(f, "mod=") || strings.HasPrefix(f, "modfile=") {
+			continue
+		}
+		buildFlags = append(buildFlags, flag)
+	}
+	inv.BuildFlags = buildFlags
+	stdoutBytes, err := r.Run(ctx, inv)
+	if err != nil {
+		return 0, err
+	}
+	stdout := stdoutBytes.String()
+	if len(stdout) < 3 {
+		return 0, fmt.Errorf("bad ReleaseTags output: %q", stdout)
+	}
+	// Split up "[go1.1 go1.15]"
+	tags := strings.Fields(stdout[1 : len(stdout)-2])
+	for i := len(tags) - 1; i >= 0; i-- {
+		var version int
+		if _, err := fmt.Sscanf(tags[i], "go1.%d", &version); err != nil {
+			continue
+		}
+		return version, nil
+	}
+	return 0, fmt.Errorf("no parseable ReleaseTags in %v", tags)
+}

vendor/golang.org/x/tools/internal/gopathwalk/walk.go

@@ -10,20 +10,22 @@ import (
 	"bufio"
 	"bytes"
 	"fmt"
-	"go/build"
 	"io/ioutil"
 	"log"
 	"os"
 	"path/filepath"
 	"strings"
+	"time"
 
 	"golang.org/x/tools/internal/fastwalk"
 )
 
 // Options controls the behavior of a Walk call.
 type Options struct {
-	Debug          bool // Enable debug logging
-	ModulesEnabled bool // Search module caches. Also disables legacy goimports ignore rules.
+	// If Logf is non-nil, debug logging is enabled through this function.
+	Logf func(format string, args ...interface{})
+	// Search module caches. Also disables legacy goimports ignore rules.
+	ModulesEnabled bool
 }
 
 // RootType indicates the type of a Root.
@@ -44,39 +46,44 @@ type Root struct {
 	Type RootType
 }
 
-// SrcDirsRoots returns the roots from build.Default.SrcDirs(). Not modules-compatible.
-func SrcDirsRoots(ctx *build.Context) []Root {
-	var roots []Root
-	roots = append(roots, Root{filepath.Join(ctx.GOROOT, "src"), RootGOROOT})
-	for _, p := range filepath.SplitList(ctx.GOPATH) {
-		roots = append(roots, Root{filepath.Join(p, "src"), RootGOPATH})
-	}
-	return roots
-}
-
 // Walk walks Go source directories ($GOROOT, $GOPATH, etc) to find packages.
 // For each package found, add will be called (concurrently) with the absolute
 // paths of the containing source directory and the package directory.
 // add will be called concurrently.
 func Walk(roots []Root, add func(root Root, dir string), opts Options) {
+	WalkSkip(roots, add, func(Root, string) bool { return false }, opts)
+}
+
+// WalkSkip walks Go source directories ($GOROOT, $GOPATH, etc) to find packages.
+// For each package found, add will be called (concurrently) with the absolute
+// paths of the containing source directory and the package directory.
+// For each directory that will be scanned, skip will be called (concurrently)
+// with the absolute paths of the containing source directory and the directory.
+// If skip returns false on a directory it will be processed.
+// add will be called concurrently.
+// skip will be called concurrently.
+func WalkSkip(roots []Root, add func(root Root, dir string), skip func(root Root, dir string) bool, opts Options) {
 	for _, root := range roots {
-		walkDir(root, add, opts)
+		walkDir(root, add, skip, opts)
 	}
 }
 
-func walkDir(root Root, add func(Root, string), opts Options) {
+// walkDir creates a walker and starts fastwalk with this walker.
+func walkDir(root Root, add func(Root, string), skip func(root Root, dir string) bool, opts Options) {
 	if _, err := os.Stat(root.Path); os.IsNotExist(err) {
-		if opts.Debug {
-			log.Printf("skipping nonexistant directory: %v", root.Path)
+		if opts.Logf != nil {
+			opts.Logf("skipping nonexistent directory: %v", root.Path)
 		}
 		return
 	}
-	if opts.Debug {
-		log.Printf("scanning %s", root.Path)
+	start := time.Now()
+	if opts.Logf != nil {
+		opts.Logf("gopathwalk: scanning %s", root.Path)
 	}
 	w := &walker{
 		root: root,
 		add:  add,
+		skip: skip,
 		opts: opts,
 	}
 	w.init()
@@ -84,21 +91,22 @@ func walkDir(root Root, add func(Root, string), opts Options) {
 		log.Printf("gopathwalk: scanning directory %v: %v", root.Path, err)
 	}
 
-	if opts.Debug {
-		log.Printf("scanned %s", root.Path)
+	if opts.Logf != nil {
+		opts.Logf("gopathwalk: scanned %s in %v", root.Path, time.Since(start))
 	}
 }
 
 // walker is the callback for fastwalk.Walk.
 type walker struct {
-	root Root               // The source directory to scan.
-	add  func(Root, string) // The callback that will be invoked for every possible Go package dir.
-	opts Options            // Options passed to Walk by the user.
+	root Root                    // The source directory to scan.
+	add  func(Root, string)      // The callback that will be invoked for every possible Go package dir.
+	skip func(Root, string) bool // The callback that will be invoked for every dir. dir is skipped if it returns true.
+	opts Options                 // Options passed to Walk by the user.
 
 	ignoredDirs []os.FileInfo // The ignored directories, loaded from .goimportsignore files.
 }
 
-// init initializes the walker based on its Options.
+// init initializes the walker based on its Options
 func (w *walker) init() {
 	var ignoredPaths []string
 	if w.root.Type == RootModuleCache {
@@ -113,11 +121,11 @@ func (w *walker) init() {
 		full := filepath.Join(w.root.Path, p)
 		if fi, err := os.Stat(full); err == nil {
 			w.ignoredDirs = append(w.ignoredDirs, fi)
-			if w.opts.Debug {
-				log.Printf("Directory added to ignore list: %s", full)
+			if w.opts.Logf != nil {
+				w.opts.Logf("Directory added to ignore list: %s", full)
 			}
-		} else if w.opts.Debug {
-			log.Printf("Error statting ignored directory: %v", err)
+		} else if w.opts.Logf != nil {
+			w.opts.Logf("Error statting ignored directory: %v", err)
 		}
 	}
 }
@@ -128,11 +136,11 @@ func (w *walker) init() {
 func (w *walker) getIgnoredDirs(path string) []string {
 	file := filepath.Join(path, ".goimportsignore")
 	slurp, err := ioutil.ReadFile(file)
-	if w.opts.Debug {
+	if w.opts.Logf != nil {
 		if err != nil {
-			log.Print(err)
+			w.opts.Logf("%v", err)
 		} else {
-			log.Printf("Read %s", file)
+			w.opts.Logf("Read %s", file)
 		}
 	}
 	if err != nil {
@@ -151,29 +159,35 @@ func (w *walker) getIgnoredDirs(path string) []string {
 	return ignoredDirs
 }
 
-func (w *walker) shouldSkipDir(fi os.FileInfo) bool {
+// shouldSkipDir reports whether the file should be skipped or not.
+func (w *walker) shouldSkipDir(fi os.FileInfo, dir string) bool {
 	for _, ignoredDir := range w.ignoredDirs {
 		if os.SameFile(fi, ignoredDir) {
 			return true
 		}
 	}
+	if w.skip != nil {
+		// Check with the user specified callback.
+		return w.skip(w.root, dir)
+	}
 	return false
 }
 
+// walk walks through the given path.
 func (w *walker) walk(path string, typ os.FileMode) error {
 	dir := filepath.Dir(path)
 	if typ.IsRegular() {
 		if dir == w.root.Path && (w.root.Type == RootGOROOT || w.root.Type == RootGOPATH) {
 			// Doesn't make sense to have regular files
 			// directly in your $GOPATH/src or $GOROOT/src.
-			return fastwalk.SkipFiles
+			return fastwalk.ErrSkipFiles
 		}
 		if !strings.HasSuffix(path, ".go") {
 			return nil
 		}
 
 		w.add(w.root, dir)
-		return fastwalk.SkipFiles
+		return fastwalk.ErrSkipFiles
 	}
 	if typ == os.ModeDir {
 		base := filepath.Base(path)
@@ -184,7 +198,7 @@ func (w *walker) walk(path string, typ os.FileMode) error {
 			return filepath.SkipDir
 		}
 		fi, err := os.Lstat(path)
-		if err == nil && w.shouldSkipDir(fi) {
+		if err == nil && w.shouldSkipDir(fi, path) {
 			return filepath.SkipDir
 		}
 		return nil
@@ -201,7 +215,7 @@ func (w *walker) walk(path string, typ os.FileMode) error {
 			return nil
 		}
 		if w.shouldTraverse(dir, fi) {
-			return fastwalk.TraverseLink
+			return fastwalk.ErrTraverseLink
 		}
 	}
 	return nil
@@ -224,7 +238,7 @@ func (w *walker) shouldTraverse(dir string, fi os.FileInfo) bool {
 	if !ts.IsDir() {
 		return false
 	}
-	if w.shouldSkipDir(ts) {
+	if w.shouldSkipDir(ts, dir) {
 		return false
 	}
 	// Check for symlink loops by statting each directory component

vendor/golang.org/x/tools/internal/imports/imports.go

@@ -6,20 +6,18 @@
 
 // Package imports implements a Go pretty-printer (like package "go/format")
 // that also adds or removes import statements as necessary.
-package imports // import "golang.org/x/tools/imports"
+package imports
 
 import (
 	"bufio"
 	"bytes"
 	"fmt"
 	"go/ast"
-	"go/build"
 	"go/format"
 	"go/parser"
 	"go/printer"
 	"go/token"
 	"io"
-	"io/ioutil"
 	"regexp"
 	"strconv"
 	"strings"
@@ -27,8 +25,15 @@ import (
 	"golang.org/x/tools/go/ast/astutil"
 )
 
-// Options specifies options for processing files.
+// Options is golang.org/x/tools/imports.Options with extra internal-only options.
 type Options struct {
+	Env *ProcessEnv // The environment to use. Note: this contains the cached module and filesystem state.
+
+	// LocalPrefix is a comma-separated string of import path prefixes, which, if
+	// set, instructs Process to sort the import paths with the given prefixes
+	// into another group after 3rd-party packages.
+	LocalPrefix string
+
 	Fragment  bool // Accept fragment of a source file (no package statement)
 	AllErrors bool // Report all errors (not just the first 10 on different lines)
 
@@ -39,29 +44,8 @@ type Options struct {
 	FormatOnly bool // Disable the insertion and deletion of imports
 }
 
-// Process formats and adjusts imports for the provided file.
-// If opt is nil the defaults are used.
-//
-// Note that filename's directory influences which imports can be chosen,
-// so it is important that filename be accurate.
-// To process data ``as if'' it were in filename, pass the data as a non-nil src.
-func Process(filename string, src []byte, opt *Options) ([]byte, error) {
-	env := &fixEnv{GOPATH: build.Default.GOPATH, GOROOT: build.Default.GOROOT}
-	return process(filename, src, opt, env)
-}
-
-func process(filename string, src []byte, opt *Options, env *fixEnv) ([]byte, error) {
-	if opt == nil {
-		opt = &Options{Comments: true, TabIndent: true, TabWidth: 8}
-	}
-	if src == nil {
-		b, err := ioutil.ReadFile(filename)
-		if err != nil {
-			return nil, err
-		}
-		src = b
-	}
-
+// Process implements golang.org/x/tools/imports.Process with explicit context in opt.Env.
+func Process(filename string, src []byte, opt *Options) (formatted []byte, err error) {
 	fileSet := token.NewFileSet()
 	file, adjust, err := parse(fileSet, filename, src, opt)
 	if err != nil {
@@ -69,12 +53,59 @@ func process(filename string, src []byte, opt *Options, env *fixEnv) ([]byte, er
 	}
 
 	if !opt.FormatOnly {
-		if err := fixImports(fileSet, file, filename, env); err != nil {
+		if err := fixImports(fileSet, file, filename, opt.Env); err != nil {
 			return nil, err
 		}
 	}
+	return formatFile(fileSet, file, src, adjust, opt)
+}
 
-	sortImports(fileSet, file)
+// FixImports returns a list of fixes to the imports that, when applied,
+// will leave the imports in the same state as Process. src and opt must
+// be specified.
+//
+// Note that filename's directory influences which imports can be chosen,
+// so it is important that filename be accurate.
+func FixImports(filename string, src []byte, opt *Options) (fixes []*ImportFix, err error) {
+	fileSet := token.NewFileSet()
+	file, _, err := parse(fileSet, filename, src, opt)
+	if err != nil {
+		return nil, err
+	}
+
+	return getFixes(fileSet, file, filename, opt.Env)
+}
+
+// ApplyFixes applies all of the fixes to the file and formats it. extraMode
+// is added in when parsing the file. src and opts must be specified, but no
+// env is needed.
+func ApplyFixes(fixes []*ImportFix, filename string, src []byte, opt *Options, extraMode parser.Mode) (formatted []byte, err error) {
+	// Don't use parse() -- we don't care about fragments or statement lists
+	// here, and we need to work with unparseable files.
+	fileSet := token.NewFileSet()
+	parserMode := parser.Mode(0)
+	if opt.Comments {
+		parserMode |= parser.ParseComments
+	}
+	if opt.AllErrors {
+		parserMode |= parser.AllErrors
+	}
+	parserMode |= extraMode
+
+	file, err := parser.ParseFile(fileSet, filename, src, parserMode)
+	if file == nil {
+		return nil, err
+	}
+
+	// Apply the fixes to the file.
+	apply(fileSet, file, fixes)
+
+	return formatFile(fileSet, file, src, nil, opt)
+}
+
+func formatFile(fileSet *token.FileSet, file *ast.File, src []byte, adjust func(orig []byte, src []byte) []byte, opt *Options) ([]byte, error) {
+	mergeImports(fileSet, file)
+	sortImports(opt.LocalPrefix, fileSet, file)
 	imps := astutil.Imports(fileSet, file)
 	var spacesBefore []string // import paths we need spaces before
 	for _, impSection := range imps {
@@ -85,7 +116,7 @@ func process(filename string, src []byte, opt *Options, env *fixEnv) ([]byte, er
 		lastGroup := -1
 		for _, importSpec := range impSection {
 			importPath, _ := strconv.Unquote(importSpec.Path.Value)
-			groupNum := importGroup(importPath)
+			groupNum := importGroup(opt.LocalPrefix, importPath)
 			if groupNum != lastGroup && lastGroup != -1 {
 				spacesBefore = append(spacesBefore, importPath)
 			}
@@ -101,7 +132,7 @@ func process(filename string, src []byte, opt *Options, env *fixEnv) ([]byte, er
 	printConfig := &printer.Config{Mode: printerMode, Tabwidth: opt.TabWidth}
 
 	var buf bytes.Buffer
-	err = printConfig.Fprint(&buf, fileSet, file)
+	err := printConfig.Fprint(&buf, fileSet, file)
 	if err != nil {
 		return nil, err
 	}

vendor/golang.org/x/tools/internal/imports/mod.go

@@ -0,0 +1,693 @@
+// Copyright 2019 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package imports
+
+import (
+	"bytes"
+	"context"
+	"encoding/json"
+	"fmt"
+	"io/ioutil"
+	"os"
+	"path"
+	"path/filepath"
+	"regexp"
+	"sort"
+	"strconv"
+	"strings"
+
+	"golang.org/x/mod/module"
+	"golang.org/x/tools/internal/gocommand"
+	"golang.org/x/tools/internal/gopathwalk"
+)
+
+// ModuleResolver implements resolver for modules using the go command as little
+// as feasible.
+type ModuleResolver struct {
+	env            *ProcessEnv
+	moduleCacheDir string
+	dummyVendorMod *gocommand.ModuleJSON // If vendoring is enabled, the pseudo-module that represents the /vendor directory.
+	roots          []gopathwalk.Root
+	scanSema       chan struct{} // scanSema prevents concurrent scans and guards scannedRoots.
+	scannedRoots   map[gopathwalk.Root]bool
+
+	initialized   bool
+	main          *gocommand.ModuleJSON
+	modsByModPath []*gocommand.ModuleJSON // All modules, ordered by # of path components in module Path...
+	modsByDir     []*gocommand.ModuleJSON // ...or Dir.
+
+	// moduleCacheCache stores information about the module cache.
+	moduleCacheCache *dirInfoCache
+	otherCache       *dirInfoCache
+}
+
+func newModuleResolver(e *ProcessEnv) *ModuleResolver {
+	r := &ModuleResolver{
+		env:      e,
+		scanSema: make(chan struct{}, 1),
+	}
+	r.scanSema <- struct{}{}
+	return r
+}
+
+func (r *ModuleResolver) init() error {
+	if r.initialized {
+		return nil
+	}
+
+	goenv, err := r.env.goEnv()
+	if err != nil {
+		return err
+	}
+	inv := gocommand.Invocation{
+		BuildFlags: r.env.BuildFlags,
+		ModFlag:    r.env.ModFlag,
+		ModFile:    r.env.ModFile,
+		Env:        r.env.env(),
+		Logf:       r.env.Logf,
+		WorkingDir: r.env.WorkingDir,
+	}
+	mainMod, vendorEnabled, err := gocommand.VendorEnabled(context.TODO(), inv, r.env.GocmdRunner)
+	if err != nil {
+		return err
+	}
+
+	if mainMod != nil && vendorEnabled {
+		// Vendor mode is on, so all the non-Main modules are irrelevant,
+		// and we need to search /vendor for everything.
+		r.main = mainMod
+		r.dummyVendorMod = &gocommand.ModuleJSON{
+			Path: "",
+			Dir:  filepath.Join(mainMod.Dir, "vendor"),
+		}
+		r.modsByModPath = []*gocommand.ModuleJSON{mainMod, r.dummyVendorMod}
+		r.modsByDir = []*gocommand.ModuleJSON{mainMod, r.dummyVendorMod}
+	} else {
+		// Vendor mode is off, so run go list -m ... to find everything.
+		err := r.initAllMods()
+		// We expect an error when running outside of a module with
+		// GO111MODULE=on. Other errors are fatal.
+		if err != nil && !strings.Contains(err.Error(), "working directory is not part of a module") {
+			return err
+		}
+	}
+
+	if gmc := r.env.Env["GOMODCACHE"]; gmc != "" {
+		r.moduleCacheDir = gmc
+	} else {
+		gopaths := filepath.SplitList(goenv["GOPATH"])
+		if len(gopaths) == 0 {
+			return fmt.Errorf("empty GOPATH")
+		}
+		r.moduleCacheDir = filepath.Join(gopaths[0], "/pkg/mod")
+	}
+
+	sort.Slice(r.modsByModPath, func(i, j int) bool {
+		count := func(x int) int {
+			return strings.Count(r.modsByModPath[x].Path, "/")
+		}
+		return count(j) < count(i) // descending order
+	})
+	sort.Slice(r.modsByDir, func(i, j int) bool {
+		count := func(x int) int {
+			return strings.Count(r.modsByDir[x].Dir, "/")
+		}
+		return count(j) < count(i) // descending order
+	})
+
+	r.roots = []gopathwalk.Root{
+		{filepath.Join(goenv["GOROOT"], "/src"), gopathwalk.RootGOROOT},
+	}
+	if r.main != nil {
+		r.roots = append(r.roots, gopathwalk.Root{r.main.Dir, gopathwalk.RootCurrentModule})
+	}
+	if vendorEnabled {
+		r.roots = append(r.roots, gopathwalk.Root{r.dummyVendorMod.Dir, gopathwalk.RootOther})
+	} else {
+		addDep := func(mod *gocommand.ModuleJSON) {
+			if mod.Replace == nil {
+				// This is redundant with the cache, but we'll skip it cheaply enough.
+				r.roots = append(r.roots, gopathwalk.Root{mod.Dir, gopathwalk.RootModuleCache})
+			} else {
+				r.roots = append(r.roots, gopathwalk.Root{mod.Dir, gopathwalk.RootOther})
+			}
+		}
+		// Walk dependent modules before scanning the full mod cache, direct deps first.
+		for _, mod := range r.modsByModPath {
+			if !mod.Indirect && !mod.Main {
+				addDep(mod)
+			}
+		}
+		for _, mod := range r.modsByModPath {
+			if mod.Indirect && !mod.Main {
+				addDep(mod)
+			}
+		}
+		r.roots = append(r.roots, gopathwalk.Root{r.moduleCacheDir, gopathwalk.RootModuleCache})
+	}
+
+	r.scannedRoots = map[gopathwalk.Root]bool{}
+	if r.moduleCacheCache == nil {
+		r.moduleCacheCache = &dirInfoCache{
+			dirs:      map[string]*directoryPackageInfo{},
+			listeners: map[*int]cacheListener{},
+		}
+	}
+	if r.otherCache == nil {
+		r.otherCache = &dirInfoCache{
+			dirs:      map[string]*directoryPackageInfo{},
+			listeners: map[*int]cacheListener{},
+		}
+	}
+	r.initialized = true
+	return nil
+}
+
+func (r *ModuleResolver) initAllMods() error {
+	stdout, err := r.env.invokeGo(context.TODO(), "list", "-m", "-e", "-json", "...")
+	if err != nil {
+		return err
+	}
+	for dec := json.NewDecoder(stdout); dec.More(); {
+		mod := &gocommand.ModuleJSON{}
+		if err := dec.Decode(mod); err != nil {
+			return err
+		}
+		if mod.Dir == "" {
+			if r.env.Logf != nil {
+				r.env.Logf("module %v has not been downloaded and will be ignored", mod.Path)
+			}
+			// Can't do anything with a module that's not downloaded.
+			continue
+		}
+		// golang/go#36193: the go command doesn't always clean paths.
+		mod.Dir = filepath.Clean(mod.Dir)
+		r.modsByModPath = append(r.modsByModPath, mod)
+		r.modsByDir = append(r.modsByDir, mod)
+		if mod.Main {
+			r.main = mod
+		}
+	}
+	return nil
+}
+
+func (r *ModuleResolver) ClearForNewScan() {
+	<-r.scanSema
+	r.scannedRoots = map[gopathwalk.Root]bool{}
+	r.otherCache = &dirInfoCache{
+		dirs:      map[string]*directoryPackageInfo{},
+		listeners: map[*int]cacheListener{},
+	}
+	r.scanSema <- struct{}{}
+}
+
+func (r *ModuleResolver) ClearForNewMod() {
+	<-r.scanSema
+	*r = ModuleResolver{
+		env:              r.env,
+		moduleCacheCache: r.moduleCacheCache,
+		otherCache:       r.otherCache,
+		scanSema:         r.scanSema,
+	}
+	r.init()
+	r.scanSema <- struct{}{}
+}
+
+// findPackage returns the module and directory that contains the package at
+// the given import path, or returns nil, "" if no module is in scope.
+func (r *ModuleResolver) findPackage(importPath string) (*gocommand.ModuleJSON, string) {
+	// This can't find packages in the stdlib, but that's harmless for all
+	// the existing code paths.
+	for _, m := range r.modsByModPath {
+		if !strings.HasPrefix(importPath, m.Path) {
+			continue
+		}
+		pathInModule := importPath[len(m.Path):]
+		pkgDir := filepath.Join(m.Dir, pathInModule)
+		if r.dirIsNestedModule(pkgDir, m) {
+			continue
+		}
+
+		if info, ok := r.cacheLoad(pkgDir); ok {
+			if loaded, err := info.reachedStatus(nameLoaded); loaded {
+				if err != nil {
+					continue // No package in this dir.
+				}
+				return m, pkgDir
+			}
+			if scanned, err := info.reachedStatus(directoryScanned); scanned && err != nil {
+				continue // Dir is unreadable, etc.
+			}
+			// This is slightly wrong: a directory doesn't have to have an
+			// importable package to count as a package for package-to-module
+			// resolution. package main or _test files should count but
+			// don't.
+			// TODO(heschi): fix this.
+			if _, err := r.cachePackageName(info); err == nil {
+				return m, pkgDir
+			}
+		}
+
+		// Not cached. Read the filesystem.
+		pkgFiles, err := ioutil.ReadDir(pkgDir)
+		if err != nil {
+			continue
+		}
+		// A module only contains a package if it has buildable go
+		// files in that directory. If not, it could be provided by an
+		// outer module. See #29736.
+		for _, fi := range pkgFiles {
+			if ok, _ := r.env.matchFile(pkgDir, fi.Name()); ok {
+				return m, pkgDir
+			}
+		}
+	}
+	return nil, ""
+}
+
+func (r *ModuleResolver) cacheLoad(dir string) (directoryPackageInfo, bool) {
+	if info, ok := r.moduleCacheCache.Load(dir); ok {
+		return info, ok
+	}
+	return r.otherCache.Load(dir)
+}
+
+func (r *ModuleResolver) cacheStore(info directoryPackageInfo) {
+	if info.rootType == gopathwalk.RootModuleCache {
+		r.moduleCacheCache.Store(info.dir, info)
+	} else {
+		r.otherCache.Store(info.dir, info)
+	}
+}
+
+func (r *ModuleResolver) cacheKeys() []string {
+	return append(r.moduleCacheCache.Keys(), r.otherCache.Keys()...)
+}
+
+// cachePackageName caches the package name for a dir already in the cache.
+func (r *ModuleResolver) cachePackageName(info directoryPackageInfo) (string, error) {
+	if info.rootType == gopathwalk.RootModuleCache {
+		return r.moduleCacheCache.CachePackageName(info)
+	}
+	return r.otherCache.CachePackageName(info)
+}
+
+func (r *ModuleResolver) cacheExports(ctx context.Context, env *ProcessEnv, info directoryPackageInfo) (string, []string, error) {
+	if info.rootType == gopathwalk.RootModuleCache {
+		return r.moduleCacheCache.CacheExports(ctx, env, info)
+	}
+	return r.otherCache.CacheExports(ctx, env, info)
+}
+
+// findModuleByDir returns the module that contains dir, or nil if no such
+// module is in scope.
+func (r *ModuleResolver) findModuleByDir(dir string) *gocommand.ModuleJSON {
+	// This is quite tricky and may not be correct. dir could be:
+	// - a package in the main module.
+	// - a replace target underneath the main module's directory.
+	//    - a nested module in the above.
+	// - a replace target somewhere totally random.
+	//    - a nested module in the above.
+	// - in the mod cache.
+	// - in /vendor/ in -mod=vendor mode.
+	//    - nested module? Dunno.
+	// Rumor has it that replace targets cannot contain other replace targets.
+	for _, m := range r.modsByDir {
+		if !strings.HasPrefix(dir, m.Dir) {
+			continue
+		}
+
+		if r.dirIsNestedModule(dir, m) {
+			continue
+		}
+
+		return m
+	}
+	return nil
+}
+
+// dirIsNestedModule reports if dir is contained in a nested module underneath
+// mod, not actually in mod.
+func (r *ModuleResolver) dirIsNestedModule(dir string, mod *gocommand.ModuleJSON) bool {
+	if !strings.HasPrefix(dir, mod.Dir) {
+		return false
+	}
+	if r.dirInModuleCache(dir) {
+		// Nested modules in the module cache are pruned,
+		// so it cannot be a nested module.
+		return false
+	}
+	if mod != nil && mod == r.dummyVendorMod {
+		// The /vendor pseudomodule is flattened and doesn't actually count.
+		return false
+	}
+	modDir, _ := r.modInfo(dir)
+	if modDir == "" {
+		return false
+	}
+	return modDir != mod.Dir
+}
+
+func (r *ModuleResolver) modInfo(dir string) (modDir string, modName string) {
+	readModName := func(modFile string) string {
+		modBytes, err := ioutil.ReadFile(modFile)
+		if err != nil {
+			return ""
+		}
+		return modulePath(modBytes)
+	}
+
+	if r.dirInModuleCache(dir) {
+		if matches := modCacheRegexp.FindStringSubmatch(dir); len(matches) == 3 {
+			index := strings.Index(dir, matches[1]+"@"+matches[2])
+			modDir := filepath.Join(dir[:index], matches[1]+"@"+matches[2])
+			return modDir, readModName(filepath.Join(modDir, "go.mod"))
+		}
+	}
+	for {
+		if info, ok := r.cacheLoad(dir); ok {
+			return info.moduleDir, info.moduleName
+		}
+		f := filepath.Join(dir, "go.mod")
+		info, err := os.Stat(f)
+		if err == nil && !info.IsDir() {
+			return dir, readModName(f)
+		}
+
+		d := filepath.Dir(dir)
+		if len(d) >= len(dir) {
+			return "", "" // reached top of file system, no go.mod
+		}
+		dir = d
+	}
+}
+
+func (r *ModuleResolver) dirInModuleCache(dir string) bool {
+	if r.moduleCacheDir == "" {
+		return false
+	}
+	return strings.HasPrefix(dir, r.moduleCacheDir)
+}
+
+func (r *ModuleResolver) loadPackageNames(importPaths []string, srcDir string) (map[string]string, error) {
+	if err := r.init(); err != nil {
+		return nil, err
+	}
+	names := map[string]string{}
+	for _, path := range importPaths {
+		_, packageDir := r.findPackage(path)
+		if packageDir == "" {
+			continue
+		}
+		name, err := packageDirToName(packageDir)
+		if err != nil {
+			continue
+		}
+		names[path] = name
+	}
+	return names, nil
+}
+
+func (r *ModuleResolver) scan(ctx context.Context, callback *scanCallback) error {
+	if err := r.init(); err != nil {
+		return err
+	}
+
+	processDir := func(info directoryPackageInfo) {
+		// Skip this directory if we were not able to get the package information successfully.
+		if scanned, err := info.reachedStatus(directoryScanned); !scanned || err != nil {
+			return
+		}
+		pkg, err := r.canonicalize(info)
+		if err != nil {
+			return
+		}
+
+		if !callback.dirFound(pkg) {
+			return
+		}
+		pkg.packageName, err = r.cachePackageName(info)
+		if err != nil {
+			return
+		}
+
+		if !callback.packageNameLoaded(pkg) {
+			return
+		}
+		_, exports, err := r.loadExports(ctx, pkg, false)
+		if err != nil {
+			return
+		}
+		callback.exportsLoaded(pkg, exports)
+	}
+
+	// Start processing everything in the cache, and listen for the new stuff
+	// we discover in the walk below.
+	stop1 := r.moduleCacheCache.ScanAndListen(ctx, processDir)
+	defer stop1()
+	stop2 := r.otherCache.ScanAndListen(ctx, processDir)
+	defer stop2()
+
+	// We assume cached directories are fully cached, including all their
+	// children, and have not changed. We can skip them.
+	skip := func(root gopathwalk.Root, dir string) bool {
+		info, ok := r.cacheLoad(dir)
+		if !ok {
+			return false
+		}
+		// This directory can be skipped as long as we have already scanned it.
+		// Packages with errors will continue to have errors, so there is no need
+		// to rescan them.
+		packageScanned, _ := info.reachedStatus(directoryScanned)
+		return packageScanned
+	}
+
+	// Add anything new to the cache, and process it if we're still listening.
+	add := func(root gopathwalk.Root, dir string) {
+		r.cacheStore(r.scanDirForPackage(root, dir))
+	}
+
+	// r.roots and the callback are not necessarily safe to use in the
+	// goroutine below. Process them eagerly.
+	roots := filterRoots(r.roots, callback.rootFound)
+	// We can't cancel walks, because we need them to finish to have a usable
+	// cache. Instead, run them in a separate goroutine and detach.
+	scanDone := make(chan struct{})
+	go func() {
+		select {
+		case <-ctx.Done():
+			return
+		case <-r.scanSema:
+		}
+		defer func() { r.scanSema <- struct{}{} }()
+		// We have the lock on r.scannedRoots, and no other scans can run.
+		for _, root := range roots {
+			if ctx.Err() != nil {
+				return
+			}
+
+			if r.scannedRoots[root] {
+				continue
+			}
+			gopathwalk.WalkSkip([]gopathwalk.Root{root}, add, skip, gopathwalk.Options{Logf: r.env.Logf, ModulesEnabled: true})
+			r.scannedRoots[root] = true
+		}
+		close(scanDone)
+	}()
+	select {
+	case <-ctx.Done():
+	case <-scanDone:
+	}
+	return nil
+}
+
+func (r *ModuleResolver) scoreImportPath(ctx context.Context, path string) float64 {
+	if _, ok := stdlib[path]; ok {
+		return MaxRelevance
+	}
+	mod, _ := r.findPackage(path)
+	return modRelevance(mod)
+}
+
+func modRelevance(mod *gocommand.ModuleJSON) float64 {
+	var relevance float64
+	switch {
+	case mod == nil: // out of scope
+		return MaxRelevance - 4
+	case mod.Indirect:
+		relevance = MaxRelevance - 3
+	case !mod.Main:
+		relevance = MaxRelevance - 2
+	default:
+		relevance = MaxRelevance - 1 // main module ties with stdlib
+	}
+
+	_, versionString, ok := module.SplitPathVersion(mod.Path)
+	if ok {
+		index := strings.Index(versionString, "v")
+		if index == -1 {
+			return relevance
+		}
+		if versionNumber, err := strconv.ParseFloat(versionString[index+1:], 64); err == nil {
+			relevance += versionNumber / 1000
+		}
+	}
+
+	return relevance
+}
+
+// canonicalize gets the result of canonicalizing the packages using the results
+// of initializing the resolver from 'go list -m'.
+func (r *ModuleResolver) canonicalize(info directoryPackageInfo) (*pkg, error) {
+	// Packages in GOROOT are already canonical, regardless of the std/cmd modules.
+	if info.rootType == gopathwalk.RootGOROOT {
+		return &pkg{
+			importPathShort: info.nonCanonicalImportPath,
+			dir:             info.dir,
+			packageName:     path.Base(info.nonCanonicalImportPath),
+			relevance:       MaxRelevance,
+		}, nil
+	}
+
+	importPath := info.nonCanonicalImportPath
+	mod := r.findModuleByDir(info.dir)
+	// Check if the directory is underneath a module that's in scope.
+	if mod != nil {
+		// It is. If dir is the target of a replace directive,
+		// our guessed import path is wrong. Use the real one.
+		if mod.Dir == info.dir {
+			importPath = mod.Path
+		} else {
+			dirInMod := info.dir[len(mod.Dir)+len("/"):]
+			importPath = path.Join(mod.Path, filepath.ToSlash(dirInMod))
+		}
+	} else if !strings.HasPrefix(importPath, info.moduleName) {
+		// The module's name doesn't match the package's import path. It
+		// probably needs a replace directive we don't have.
+		return nil, fmt.Errorf("package in %q is not valid without a replace statement", info.dir)
+	}
+
+	res := &pkg{
+		importPathShort: importPath,
+		dir:             info.dir,
+		relevance:       modRelevance(mod),
+	}
+	// We may have discovered a package that has a different version
+	// in scope already. Canonicalize to that one if possible.
+	if _, canonicalDir := r.findPackage(importPath); canonicalDir != "" {
+		res.dir = canonicalDir
+	}
+	return res, nil
+}
+
+func (r *ModuleResolver) loadExports(ctx context.Context, pkg *pkg, includeTest bool) (string, []string, error) {
+	if err := r.init(); err != nil {
+		return "", nil, err
+	}
+	if info, ok := r.cacheLoad(pkg.dir); ok && !includeTest {
+		return r.cacheExports(ctx, r.env, info)
+	}
+	return loadExportsFromFiles(ctx, r.env, pkg.dir, includeTest)
+}
+
+func (r *ModuleResolver) scanDirForPackage(root gopathwalk.Root, dir string) directoryPackageInfo {
+	subdir := ""
+	if dir != root.Path {
+		subdir = dir[len(root.Path)+len("/"):]
+	}
+	importPath := filepath.ToSlash(subdir)
+	if strings.HasPrefix(importPath, "vendor/") {
+		// Only enter vendor directories if they're explicitly requested as a root.
+		return directoryPackageInfo{
+			status: directoryScanned,
+			err:    fmt.Errorf("unwanted vendor directory"),
+		}
+	}
+	switch root.Type {
+	case gopathwalk.RootCurrentModule:
+		importPath = path.Join(r.main.Path, filepath.ToSlash(subdir))
+	case gopathwalk.RootModuleCache:
+		matches := modCacheRegexp.FindStringSubmatch(subdir)
+		if len(matches) == 0 {
+			return directoryPackageInfo{
+				status: directoryScanned,
+				err:    fmt.Errorf("invalid module cache path: %v", subdir),
+			}
+		}
+		modPath, err := module.UnescapePath(filepath.ToSlash(matches[1]))
+		if err != nil {
+			if r.env.Logf != nil {
+				r.env.Logf("decoding module cache path %q: %v", subdir, err)
+			}
+			return directoryPackageInfo{
+				status: directoryScanned,
+				err:    fmt.Errorf("decoding module cache path %q: %v", subdir, err),
+			}
+		}
+		importPath = path.Join(modPath, filepath.ToSlash(matches[3]))
+	}
+
+	modDir, modName := r.modInfo(dir)
+	result := directoryPackageInfo{
+		status:                 directoryScanned,
+		dir:                    dir,
+		rootType:               root.Type,
+		nonCanonicalImportPath: importPath,
+		moduleDir:              modDir,
+		moduleName:             modName,
+	}
+	if root.Type == gopathwalk.RootGOROOT {
+		// stdlib packages are always in scope, despite the confusing go.mod
+		return result
+	}
+	return result
+}
+
+// modCacheRegexp splits a path in a module cache into module, module version, and package.
+var modCacheRegexp = regexp.MustCompile(`(.*)@([^/\\]*)(.*)`)
+
+var (
+	slashSlash = []byte("//")
+	moduleStr  = []byte("module")
+)
+
+// modulePath returns the module path from the gomod file text.
+// If it cannot find a module path, it returns an empty string.
+// It is tolerant of unrelated problems in the go.mod file.
+//
+// Copied from cmd/go/internal/modfile.
+func modulePath(mod []byte) string {
+	for len(mod) > 0 {
+		line := mod
+		mod = nil
+		if i := bytes.IndexByte(line, '\n'); i >= 0 {
+			line, mod = line[:i], line[i+1:]
+		}
+		if i := bytes.Index(line, slashSlash); i >= 0 {
+			line = line[:i]
+		}
+		line = bytes.TrimSpace(line)
+		if !bytes.HasPrefix(line, moduleStr) {
+			continue
+		}
+		line = line[len(moduleStr):]
+		n := len(line)
+		line = bytes.TrimSpace(line)
+		if len(line) == n || len(line) == 0 {
+			continue
+		}
+
+		if line[0] == '"' || line[0] == '`' {
+			p, err := strconv.Unquote(string(line))
+			if err != nil {
+				return "" // malformed quoted string or multiline module path
+			}
+			return p
+		}
+
+		return string(line)
+	}
+	return "" // missing module path
+}

vendor/golang.org/x/tools/internal/imports/mod_cache.go

@@ -0,0 +1,236 @@
+// Copyright 2019 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package imports
+
+import (
+	"context"
+	"fmt"
+	"sync"
+
+	"golang.org/x/tools/internal/gopathwalk"
+)
+
+// To find packages to import, the resolver needs to know about all of the
+// the packages that could be imported. This includes packages that are
+// already in modules that are in (1) the current module, (2) replace targets,
+// and (3) packages in the module cache. Packages in (1) and (2) may change over
+// time, as the client may edit the current module and locally replaced modules.
+// The module cache (which includes all of the packages in (3)) can only
+// ever be added to.
+//
+// The resolver can thus save state about packages in the module cache
+// and guarantee that this will not change over time. To obtain information
+// about new modules added to the module cache, the module cache should be
+// rescanned.
+//
+// It is OK to serve information about modules that have been deleted,
+// as they do still exist.
+// TODO(suzmue): can we share information with the caller about
+// what module needs to be downloaded to import this package?
+
+type directoryPackageStatus int
+
+const (
+	_ directoryPackageStatus = iota
+	directoryScanned
+	nameLoaded
+	exportsLoaded
+)
+
+type directoryPackageInfo struct {
+	// status indicates the extent to which this struct has been filled in.
+	status directoryPackageStatus
+	// err is non-nil when there was an error trying to reach status.
+	err error
+
+	// Set when status >= directoryScanned.
+
+	// dir is the absolute directory of this package.
+	dir      string
+	rootType gopathwalk.RootType
+	// nonCanonicalImportPath is the package's expected import path. It may
+	// not actually be importable at that path.
+	nonCanonicalImportPath string
+
+	// Module-related information.
+	moduleDir  string // The directory that is the module root of this dir.
+	moduleName string // The module name that contains this dir.
+
+	// Set when status >= nameLoaded.
+
+	packageName string // the package name, as declared in the source.
+
+	// Set when status >= exportsLoaded.
+
+	exports []string
+}
+
+// reachedStatus returns true when info has a status at least target and any error associated with
+// an attempt to reach target.
+func (info *directoryPackageInfo) reachedStatus(target directoryPackageStatus) (bool, error) {
+	if info.err == nil {
+		return info.status >= target, nil
+	}
+	if info.status == target {
+		return true, info.err
+	}
+	return true, nil
+}
+
+// dirInfoCache is a concurrency safe map for storing information about
+// directories that may contain packages.
+//
+// The information in this cache is built incrementally. Entries are initialized in scan.
+// No new keys should be added in any other functions, as all directories containing
+// packages are identified in scan.
+//
+// Other functions, including loadExports and findPackage, may update entries in this cache
+// as they discover new things about the directory.
+//
+// The information in the cache is not expected to change for the cache's
+// lifetime, so there is no protection against competing writes. Users should
+// take care not to hold the cache across changes to the underlying files.
+//
+// TODO(suzmue): consider other concurrency strategies and data structures (RWLocks, sync.Map, etc)
+type dirInfoCache struct {
+	mu sync.Mutex
+	// dirs stores information about packages in directories, keyed by absolute path.
+	dirs      map[string]*directoryPackageInfo
+	listeners map[*int]cacheListener
+}
+
+type cacheListener func(directoryPackageInfo)
+
+// ScanAndListen calls listener on all the items in the cache, and on anything
+// newly added. The returned stop function waits for all in-flight callbacks to
+// finish and blocks new ones.
+func (d *dirInfoCache) ScanAndListen(ctx context.Context, listener cacheListener) func() {
+	ctx, cancel := context.WithCancel(ctx)
+
+	// Flushing out all the callbacks is tricky without knowing how many there
+	// are going to be. Setting an arbitrary limit makes it much easier.
+	const maxInFlight = 10
+	sema := make(chan struct{}, maxInFlight)
+	for i := 0; i < maxInFlight; i++ {
+		sema <- struct{}{}
+	}
+
+	cookie := new(int) // A unique ID we can use for the listener.
+
+	// We can't hold mu while calling the listener.
+	d.mu.Lock()
+	var keys []string
+	for key := range d.dirs {
+		keys = append(keys, key)
+	}
+	d.listeners[cookie] = func(info directoryPackageInfo) {
+		select {
+		case <-ctx.Done():
+			return
+		case <-sema:
+		}
+		listener(info)
+		sema <- struct{}{}
+	}
+	d.mu.Unlock()
+
+	stop := func() {
+		cancel()
+		d.mu.Lock()
+		delete(d.listeners, cookie)
+		d.mu.Unlock()
+		for i := 0; i < maxInFlight; i++ {
+			<-sema
+		}
+	}
+
+	// Process the pre-existing keys.
+	for _, k := range keys {
+		select {
+		case <-ctx.Done():
+			return stop
+		default:
+		}
+		if v, ok := d.Load(k); ok {
+			listener(v)
+		}
+	}
+
+	return stop
+}
+
+// Store stores the package info for dir.
+func (d *dirInfoCache) Store(dir string, info directoryPackageInfo) {
+	d.mu.Lock()
+	_, old := d.dirs[dir]
+	d.dirs[dir] = &info
+	var listeners []cacheListener
+	for _, l := range d.listeners {
+		listeners = append(listeners, l)
+	}
+	d.mu.Unlock()
+
+	if !old {
+		for _, l := range listeners {
+			l(info)
+		}
+	}
+}
+
+// Load returns a copy of the directoryPackageInfo for absolute directory dir.
+func (d *dirInfoCache) Load(dir string) (directoryPackageInfo, bool) {
+	d.mu.Lock()
+	defer d.mu.Unlock()
+	info, ok := d.dirs[dir]
+	if !ok {
+		return directoryPackageInfo{}, false
+	}
+	return *info, true
+}
+
+// Keys returns the keys currently present in d.
+func (d *dirInfoCache) Keys() (keys []string) {
+	d.mu.Lock()
+	defer d.mu.Unlock()
+	for key := range d.dirs {
+		keys = append(keys, key)
+	}
+	return keys
+}
+
+func (d *dirInfoCache) CachePackageName(info directoryPackageInfo) (string, error) {
+	if loaded, err := info.reachedStatus(nameLoaded); loaded {
+		return info.packageName, err
+	}
+	if scanned, err := info.reachedStatus(directoryScanned); !scanned || err != nil {
+		return "", fmt.Errorf("cannot read package name, scan error: %v", err)
+	}
+	info.packageName, info.err = packageDirToName(info.dir)
+	info.status = nameLoaded
+	d.Store(info.dir, info)
+	return info.packageName, info.err
+}
+
+func (d *dirInfoCache) CacheExports(ctx context.Context, env *ProcessEnv, info directoryPackageInfo) (string, []string, error) {
+	if reached, _ := info.reachedStatus(exportsLoaded); reached {
+		return info.packageName, info.exports, info.err
+	}
+	if reached, err := info.reachedStatus(nameLoaded); reached && err != nil {
+		return "", nil, err
+	}
+	info.packageName, info.exports, info.err = loadExportsFromFiles(ctx, env, info.dir, false)
+	if info.err == context.Canceled || info.err == context.DeadlineExceeded {
+		return info.packageName, info.exports, info.err
+	}
+	// The cache structure wants things to proceed linearly. We can skip a
+	// step here, but only if we succeed.
+	if info.status == nameLoaded || info.err == nil {
+		info.status = exportsLoaded
+	} else {
+		info.status = nameLoaded
+	}
+	d.Store(info.dir, info)
+	return info.packageName, info.exports, info.err
+}

vendor/golang.org/x/tools/internal/imports/sortimports.go

@@ -15,7 +15,7 @@ import (
 
 // sortImports sorts runs of consecutive import lines in import blocks in f.
 // It also removes duplicate imports when it is possible to do so without data loss.
-func sortImports(fset *token.FileSet, f *ast.File) {
+func sortImports(localPrefix string, fset *token.FileSet, f *ast.File) {
 	for i, d := range f.Decls {
 		d, ok := d.(*ast.GenDecl)
 		if !ok || d.Tok != token.IMPORT {
@@ -40,11 +40,11 @@ func sortImports(fset *token.FileSet, f *ast.File) {
 		for j, s := range d.Specs {
 			if j > i && fset.Position(s.Pos()).Line > 1+fset.Position(d.Specs[j-1].End()).Line {
 				// j begins a new run.  End this one.
-				specs = append(specs, sortSpecs(fset, f, d.Specs[i:j])...)
+				specs = append(specs, sortSpecs(localPrefix, fset, f, d.Specs[i:j])...)
 				i = j
 			}
 		}
-		specs = append(specs, sortSpecs(fset, f, d.Specs[i:])...)
+		specs = append(specs, sortSpecs(localPrefix, fset, f, d.Specs[i:])...)
 		d.Specs = specs
 
 		// Deduping can leave a blank line before the rparen; clean that up.
@@ -58,6 +58,53 @@ func sortImports(fset *token.FileSet, f *ast.File) {
 	}
 }
 
+// mergeImports merges all the import declarations into the first one.
+// Taken from golang.org/x/tools/ast/astutil.
+func mergeImports(fset *token.FileSet, f *ast.File) {
+	if len(f.Decls) <= 1 {
+		return
+	}
+
+	// Merge all the import declarations into the first one.
+	var first *ast.GenDecl
+	for i := 0; i < len(f.Decls); i++ {
+		decl := f.Decls[i]
+		gen, ok := decl.(*ast.GenDecl)
+		if !ok || gen.Tok != token.IMPORT || declImports(gen, "C") {
+			continue
+		}
+		if first == nil {
+			first = gen
+			continue // Don't touch the first one.
+		}
+		// We now know there is more than one package in this import
+		// declaration. Ensure that it ends up parenthesized.
+		first.Lparen = first.Pos()
+		// Move the imports of the other import declaration to the first one.
+		for _, spec := range gen.Specs {
+			spec.(*ast.ImportSpec).Path.ValuePos = first.Pos()
+			first.Specs = append(first.Specs, spec)
+		}
+		f.Decls = append(f.Decls[:i], f.Decls[i+1:]...)
+		i--
+	}
+}
+
+// declImports reports whether gen contains an import of path.
+// Taken from golang.org/x/tools/ast/astutil.
+func declImports(gen *ast.GenDecl, path string) bool {
+	if gen.Tok != token.IMPORT {
+		return false
+	}
+	for _, spec := range gen.Specs {
+		impspec := spec.(*ast.ImportSpec)
+		if importPath(impspec) == path {
+			return true
+		}
+	}
+	return false
+}
+
 func importPath(s ast.Spec) string {
 	t, err := strconv.Unquote(s.(*ast.ImportSpec).Path.Value)
 	if err == nil {
@@ -95,7 +142,7 @@ type posSpan struct {
 	End   token.Pos
 }
 
-func sortSpecs(fset *token.FileSet, f *ast.File, specs []ast.Spec) []ast.Spec {
+func sortSpecs(localPrefix string, fset *token.FileSet, f *ast.File, specs []ast.Spec) []ast.Spec {
 	// Can't short-circuit here even if specs are already sorted,
 	// since they might yet need deduplication.
 	// A lone import, however, may be safely ignored.
@@ -144,7 +191,7 @@ func sortSpecs(fset *token.FileSet, f *ast.File, specs []ast.Spec) []ast.Spec {
 	// Reassign the import paths to have the same position sequence.
 	// Reassign each comment to abut the end of its spec.
 	// Sort the comments by new position.
-	sort.Sort(byImportSpec(specs))
+	sort.Sort(byImportSpec{localPrefix, specs})
 
 	// Dedup. Thanks to our sorting, we can just consider
 	// adjacent pairs of imports.
@@ -197,16 +244,19 @@ func sortSpecs(fset *token.FileSet, f *ast.File, specs []ast.Spec) []ast.Spec {
 	return specs
 }
 
-type byImportSpec []ast.Spec // slice of *ast.ImportSpec
+type byImportSpec struct {
+	localPrefix string
+	specs       []ast.Spec // slice of *ast.ImportSpec
+}
 
-func (x byImportSpec) Len() int      { return len(x) }
-func (x byImportSpec) Swap(i, j int) { x[i], x[j] = x[j], x[i] }
+func (x byImportSpec) Len() int      { return len(x.specs) }
+func (x byImportSpec) Swap(i, j int) { x.specs[i], x.specs[j] = x.specs[j], x.specs[i] }
 func (x byImportSpec) Less(i, j int) bool {
-	ipath := importPath(x[i])
-	jpath := importPath(x[j])
+	ipath := importPath(x.specs[i])
+	jpath := importPath(x.specs[j])
 
-	igroup := importGroup(ipath)
-	jgroup := importGroup(jpath)
+	igroup := importGroup(x.localPrefix, ipath)
+	jgroup := importGroup(x.localPrefix, jpath)
 	if igroup != jgroup {
 		return igroup < jgroup
 	}
@@ -214,13 +264,13 @@ func (x byImportSpec) Less(i, j int) bool {
 	if ipath != jpath {
 		return ipath < jpath
 	}
-	iname := importName(x[i])
-	jname := importName(x[j])
+	iname := importName(x.specs[i])
+	jname := importName(x.specs[j])
 
 	if iname != jname {
 		return iname < jname
 	}
-	return importComment(x[i]) < importComment(x[j])
+	return importComment(x.specs[i]) < importComment(x.specs[j])
 }
 
 type byCommentPos []*ast.CommentGroup

vendor/golang.org/x/tools/internal/module/module.go

@@ -1,540 +0,0 @@
-// Copyright 2018 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-// Package module defines the module.Version type
-// along with support code.
-package module
-
-// IMPORTANT NOTE
-//
-// This file essentially defines the set of valid import paths for the go command.
-// There are many subtle considerations, including Unicode ambiguity,
-// security, network, and file system representations.
-//
-// This file also defines the set of valid module path and version combinations,
-// another topic with many subtle considerations.
-//
-// Changes to the semantics in this file require approval from rsc.
-
-import (
-	"fmt"
-	"sort"
-	"strings"
-	"unicode"
-	"unicode/utf8"
-
-	"golang.org/x/tools/internal/semver"
-)
-
-// A Version is defined by a module path and version pair.
-type Version struct {
-	Path string
-
-	// Version is usually a semantic version in canonical form.
-	// There are two exceptions to this general rule.
-	// First, the top-level target of a build has no specific version
-	// and uses Version = "".
-	// Second, during MVS calculations the version "none" is used
-	// to represent the decision to take no version of a given module.
-	Version string `json:",omitempty"`
-}
-
-// Check checks that a given module path, version pair is valid.
-// In addition to the path being a valid module path
-// and the version being a valid semantic version,
-// the two must correspond.
-// For example, the path "yaml/v2" only corresponds to
-// semantic versions beginning with "v2.".
-func Check(path, version string) error {
-	if err := CheckPath(path); err != nil {
-		return err
-	}
-	if !semver.IsValid(version) {
-		return fmt.Errorf("malformed semantic version %v", version)
-	}
-	_, pathMajor, _ := SplitPathVersion(path)
-	if !MatchPathMajor(version, pathMajor) {
-		if pathMajor == "" {
-			pathMajor = "v0 or v1"
-		}
-		if pathMajor[0] == '.' { // .v1
-			pathMajor = pathMajor[1:]
-		}
-		return fmt.Errorf("mismatched module path %v and version %v (want %v)", path, version, pathMajor)
-	}
-	return nil
-}
-
-// firstPathOK reports whether r can appear in the first element of a module path.
-// The first element of the path must be an LDH domain name, at least for now.
-// To avoid case ambiguity, the domain name must be entirely lower case.
-func firstPathOK(r rune) bool {
-	return r == '-' || r == '.' ||
-		'0' <= r && r <= '9' ||
-		'a' <= r && r <= 'z'
-}
-
-// pathOK reports whether r can appear in an import path element.
-// Paths can be ASCII letters, ASCII digits, and limited ASCII punctuation: + - . _ and ~.
-// This matches what "go get" has historically recognized in import paths.
-// TODO(rsc): We would like to allow Unicode letters, but that requires additional
-// care in the safe encoding (see note below).
-func pathOK(r rune) bool {
-	if r < utf8.RuneSelf {
-		return r == '+' || r == '-' || r == '.' || r == '_' || r == '~' ||
-			'0' <= r && r <= '9' ||
-			'A' <= r && r <= 'Z' ||
-			'a' <= r && r <= 'z'
-	}
-	return false
-}
-
-// fileNameOK reports whether r can appear in a file name.
-// For now we allow all Unicode letters but otherwise limit to pathOK plus a few more punctuation characters.
-// If we expand the set of allowed characters here, we have to
-// work harder at detecting potential case-folding and normalization collisions.
-// See note about "safe encoding" below.
-func fileNameOK(r rune) bool {
-	if r < utf8.RuneSelf {
-		// Entire set of ASCII punctuation, from which we remove characters:
-		//     ! " # $ % & ' ( ) * + , - . / : ; < = > ? @ [ \ ] ^ _ ` { | } ~
-		// We disallow some shell special characters: " ' * < > ? ` |
-		// (Note that some of those are disallowed by the Windows file system as well.)
-		// We also disallow path separators / : and \ (fileNameOK is only called on path element characters).
-		// We allow spaces (U+0020) in file names.
-		const allowed = "!#$%&()+,-.=@[]^_{}~ "
-		if '0' <= r && r <= '9' || 'A' <= r && r <= 'Z' || 'a' <= r && r <= 'z' {
-			return true
-		}
-		for i := 0; i < len(allowed); i++ {
-			if rune(allowed[i]) == r {
-				return true
-			}
-		}
-		return false
-	}
-	// It may be OK to add more ASCII punctuation here, but only carefully.
-	// For example Windows disallows < > \, and macOS disallows :, so we must not allow those.
-	return unicode.IsLetter(r)
-}
-
-// CheckPath checks that a module path is valid.
-func CheckPath(path string) error {
-	if err := checkPath(path, false); err != nil {
-		return fmt.Errorf("malformed module path %q: %v", path, err)
-	}
-	i := strings.Index(path, "/")
-	if i < 0 {
-		i = len(path)
-	}
-	if i == 0 {
-		return fmt.Errorf("malformed module path %q: leading slash", path)
-	}
-	if !strings.Contains(path[:i], ".") {
-		return fmt.Errorf("malformed module path %q: missing dot in first path element", path)
-	}
-	if path[0] == '-' {
-		return fmt.Errorf("malformed module path %q: leading dash in first path element", path)
-	}
-	for _, r := range path[:i] {
-		if !firstPathOK(r) {
-			return fmt.Errorf("malformed module path %q: invalid char %q in first path element", path, r)
-		}
-	}
-	if _, _, ok := SplitPathVersion(path); !ok {
-		return fmt.Errorf("malformed module path %q: invalid version", path)
-	}
-	return nil
-}
-
-// CheckImportPath checks that an import path is valid.
-func CheckImportPath(path string) error {
-	if err := checkPath(path, false); err != nil {
-		return fmt.Errorf("malformed import path %q: %v", path, err)
-	}
-	return nil
-}
-
-// checkPath checks that a general path is valid.
-// It returns an error describing why but not mentioning path.
-// Because these checks apply to both module paths and import paths,
-// the caller is expected to add the "malformed ___ path %q: " prefix.
-// fileName indicates whether the final element of the path is a file name
-// (as opposed to a directory name).
-func checkPath(path string, fileName bool) error {
-	if !utf8.ValidString(path) {
-		return fmt.Errorf("invalid UTF-8")
-	}
-	if path == "" {
-		return fmt.Errorf("empty string")
-	}
-	if strings.Contains(path, "..") {
-		return fmt.Errorf("double dot")
-	}
-	if strings.Contains(path, "//") {
-		return fmt.Errorf("double slash")
-	}
-	if path[len(path)-1] == '/' {
-		return fmt.Errorf("trailing slash")
-	}
-	elemStart := 0
-	for i, r := range path {
-		if r == '/' {
-			if err := checkElem(path[elemStart:i], fileName); err != nil {
-				return err
-			}
-			elemStart = i + 1
-		}
-	}
-	if err := checkElem(path[elemStart:], fileName); err != nil {
-		return err
-	}
-	return nil
-}
-
-// checkElem checks whether an individual path element is valid.
-// fileName indicates whether the element is a file name (not a directory name).
-func checkElem(elem string, fileName bool) error {
-	if elem == "" {
-		return fmt.Errorf("empty path element")
-	}
-	if strings.Count(elem, ".") == len(elem) {
-		return fmt.Errorf("invalid path element %q", elem)
-	}
-	if elem[0] == '.' && !fileName {
-		return fmt.Errorf("leading dot in path element")
-	}
-	if elem[len(elem)-1] == '.' {
-		return fmt.Errorf("trailing dot in path element")
-	}
-	charOK := pathOK
-	if fileName {
-		charOK = fileNameOK
-	}
-	for _, r := range elem {
-		if !charOK(r) {
-			return fmt.Errorf("invalid char %q", r)
-		}
-	}
-
-	// Windows disallows a bunch of path elements, sadly.
-	// See https://docs.microsoft.com/en-us/windows/desktop/fileio/naming-a-file
-	short := elem
-	if i := strings.Index(short, "."); i >= 0 {
-		short = short[:i]
-	}
-	for _, bad := range badWindowsNames {
-		if strings.EqualFold(bad, short) {
-			return fmt.Errorf("disallowed path element %q", elem)
-		}
-	}
-	return nil
-}
-
-// CheckFilePath checks whether a slash-separated file path is valid.
-func CheckFilePath(path string) error {
-	if err := checkPath(path, true); err != nil {
-		return fmt.Errorf("malformed file path %q: %v", path, err)
-	}
-	return nil
-}
-
-// badWindowsNames are the reserved file path elements on Windows.
-// See https://docs.microsoft.com/en-us/windows/desktop/fileio/naming-a-file
-var badWindowsNames = []string{
-	"CON",
-	"PRN",
-	"AUX",
-	"NUL",
-	"COM1",
-	"COM2",
-	"COM3",
-	"COM4",
-	"COM5",
-	"COM6",
-	"COM7",
-	"COM8",
-	"COM9",
-	"LPT1",
-	"LPT2",
-	"LPT3",
-	"LPT4",
-	"LPT5",
-	"LPT6",
-	"LPT7",
-	"LPT8",
-	"LPT9",
-}
-
-// SplitPathVersion returns prefix and major version such that prefix+pathMajor == path
-// and version is either empty or "/vN" for N >= 2.
-// As a special case, gopkg.in paths are recognized directly;
-// they require ".vN" instead of "/vN", and for all N, not just N >= 2.
-func SplitPathVersion(path string) (prefix, pathMajor string, ok bool) {
-	if strings.HasPrefix(path, "gopkg.in/") {
-		return splitGopkgIn(path)
-	}
-
-	i := len(path)
-	dot := false
-	for i > 0 && ('0' <= path[i-1] && path[i-1] <= '9' || path[i-1] == '.') {
-		if path[i-1] == '.' {
-			dot = true
-		}
-		i--
-	}
-	if i <= 1 || i == len(path) || path[i-1] != 'v' || path[i-2] != '/' {
-		return path, "", true
-	}
-	prefix, pathMajor = path[:i-2], path[i-2:]
-	if dot || len(pathMajor) <= 2 || pathMajor[2] == '0' || pathMajor == "/v1" {
-		return path, "", false
-	}
-	return prefix, pathMajor, true
-}
-
-// splitGopkgIn is like SplitPathVersion but only for gopkg.in paths.
-func splitGopkgIn(path string) (prefix, pathMajor string, ok bool) {
-	if !strings.HasPrefix(path, "gopkg.in/") {
-		return path, "", false
-	}
-	i := len(path)
-	if strings.HasSuffix(path, "-unstable") {
-		i -= len("-unstable")
-	}
-	for i > 0 && ('0' <= path[i-1] && path[i-1] <= '9') {
-		i--
-	}
-	if i <= 1 || path[i-1] != 'v' || path[i-2] != '.' {
-		// All gopkg.in paths must end in vN for some N.
-		return path, "", false
-	}
-	prefix, pathMajor = path[:i-2], path[i-2:]
-	if len(pathMajor) <= 2 || pathMajor[2] == '0' && pathMajor != ".v0" {
-		return path, "", false
-	}
-	return prefix, pathMajor, true
-}
-
-// MatchPathMajor reports whether the semantic version v
-// matches the path major version pathMajor.
-func MatchPathMajor(v, pathMajor string) bool {
-	if strings.HasPrefix(pathMajor, ".v") && strings.HasSuffix(pathMajor, "-unstable") {
-		pathMajor = strings.TrimSuffix(pathMajor, "-unstable")
-	}
-	if strings.HasPrefix(v, "v0.0.0-") && pathMajor == ".v1" {
-		// Allow old bug in pseudo-versions that generated v0.0.0- pseudoversion for gopkg .v1.
-		// For example, gopkg.in/yaml.v2@v2.2.1's go.mod requires gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405.
-		return true
-	}
-	m := semver.Major(v)
-	if pathMajor == "" {
-		return m == "v0" || m == "v1" || semver.Build(v) == "+incompatible"
-	}
-	return (pathMajor[0] == '/' || pathMajor[0] == '.') && m == pathMajor[1:]
-}
-
-// CanonicalVersion returns the canonical form of the version string v.
-// It is the same as semver.Canonical(v) except that it preserves the special build suffix "+incompatible".
-func CanonicalVersion(v string) string {
-	cv := semver.Canonical(v)
-	if semver.Build(v) == "+incompatible" {
-		cv += "+incompatible"
-	}
-	return cv
-}
-
-// Sort sorts the list by Path, breaking ties by comparing Versions.
-func Sort(list []Version) {
-	sort.Slice(list, func(i, j int) bool {
-		mi := list[i]
-		mj := list[j]
-		if mi.Path != mj.Path {
-			return mi.Path < mj.Path
-		}
-		// To help go.sum formatting, allow version/file.
-		// Compare semver prefix by semver rules,
-		// file by string order.
-		vi := mi.Version
-		vj := mj.Version
-		var fi, fj string
-		if k := strings.Index(vi, "/"); k >= 0 {
-			vi, fi = vi[:k], vi[k:]
-		}
-		if k := strings.Index(vj, "/"); k >= 0 {
-			vj, fj = vj[:k], vj[k:]
-		}
-		if vi != vj {
-			return semver.Compare(vi, vj) < 0
-		}
-		return fi < fj
-	})
-}
-
-// Safe encodings
-//
-// Module paths appear as substrings of file system paths
-// (in the download cache) and of web server URLs in the proxy protocol.
-// In general we cannot rely on file systems to be case-sensitive,
-// nor can we rely on web servers, since they read from file systems.
-// That is, we cannot rely on the file system to keep rsc.io/QUOTE
-// and rsc.io/quote separate. Windows and macOS don't.
-// Instead, we must never require two different casings of a file path.
-// Because we want the download cache to match the proxy protocol,
-// and because we want the proxy protocol to be possible to serve
-// from a tree of static files (which might be stored on a case-insensitive
-// file system), the proxy protocol must never require two different casings
-// of a URL path either.
-//
-// One possibility would be to make the safe encoding be the lowercase
-// hexadecimal encoding of the actual path bytes. This would avoid ever
-// needing different casings of a file path, but it would be fairly illegible
-// to most programmers when those paths appeared in the file system
-// (including in file paths in compiler errors and stack traces)
-// in web server logs, and so on. Instead, we want a safe encoding that
-// leaves most paths unaltered.
-//
-// The safe encoding is this:
-// replace every uppercase letter with an exclamation mark
-// followed by the letter's lowercase equivalent.
-//
-// For example,
-// github.com/Azure/azure-sdk-for-go ->  github.com/!azure/azure-sdk-for-go.
-// github.com/GoogleCloudPlatform/cloudsql-proxy -> github.com/!google!cloud!platform/cloudsql-proxy
-// github.com/Sirupsen/logrus -> github.com/!sirupsen/logrus.
-//
-// Import paths that avoid upper-case letters are left unchanged.
-// Note that because import paths are ASCII-only and avoid various
-// problematic punctuation (like : < and >), the safe encoding is also ASCII-only
-// and avoids the same problematic punctuation.
-//
-// Import paths have never allowed exclamation marks, so there is no
-// need to define how to encode a literal !.
-//
-// Although paths are disallowed from using Unicode (see pathOK above),
-// the eventual plan is to allow Unicode letters as well, to assume that
-// file systems and URLs are Unicode-safe (storing UTF-8), and apply
-// the !-for-uppercase convention. Note however that not all runes that
-// are different but case-fold equivalent are an upper/lower pair.
-// For example, U+004B ('K'), U+006B ('k'), and U+212A ('K' for Kelvin)
-// are considered to case-fold to each other. When we do add Unicode
-// letters, we must not assume that upper/lower are the only case-equivalent pairs.
-// Perhaps the Kelvin symbol would be disallowed entirely, for example.
-// Or perhaps it would encode as "!!k", or perhaps as "(212A)".
-//
-// Also, it would be nice to allow Unicode marks as well as letters,
-// but marks include combining marks, and then we must deal not
-// only with case folding but also normalization: both U+00E9 ('é')
-// and U+0065 U+0301 ('e' followed by combining acute accent)
-// look the same on the page and are treated by some file systems
-// as the same path. If we do allow Unicode marks in paths, there
-// must be some kind of normalization to allow only one canonical
-// encoding of any character used in an import path.
-
-// EncodePath returns the safe encoding of the given module path.
-// It fails if the module path is invalid.
-func EncodePath(path string) (encoding string, err error) {
-	if err := CheckPath(path); err != nil {
-		return "", err
-	}
-
-	return encodeString(path)
-}
-
-// EncodeVersion returns the safe encoding of the given module version.
-// Versions are allowed to be in non-semver form but must be valid file names
-// and not contain exclamation marks.
-func EncodeVersion(v string) (encoding string, err error) {
-	if err := checkElem(v, true); err != nil || strings.Contains(v, "!") {
-		return "", fmt.Errorf("disallowed version string %q", v)
-	}
-	return encodeString(v)
-}
-
-func encodeString(s string) (encoding string, err error) {
-	haveUpper := false
-	for _, r := range s {
-		if r == '!' || r >= utf8.RuneSelf {
-			// This should be disallowed by CheckPath, but diagnose anyway.
-			// The correctness of the encoding loop below depends on it.
-			return "", fmt.Errorf("internal error: inconsistency in EncodePath")
-		}
-		if 'A' <= r && r <= 'Z' {
-			haveUpper = true
-		}
-	}
-
-	if !haveUpper {
-		return s, nil
-	}
-
-	var buf []byte
-	for _, r := range s {
-		if 'A' <= r && r <= 'Z' {
-			buf = append(buf, '!', byte(r+'a'-'A'))
-		} else {
-			buf = append(buf, byte(r))
-		}
-	}
-	return string(buf), nil
-}
-
-// DecodePath returns the module path of the given safe encoding.
-// It fails if the encoding is invalid or encodes an invalid path.
-func DecodePath(encoding string) (path string, err error) {
-	path, ok := decodeString(encoding)
-	if !ok {
-		return "", fmt.Errorf("invalid module path encoding %q", encoding)
-	}
-	if err := CheckPath(path); err != nil {
-		return "", fmt.Errorf("invalid module path encoding %q: %v", encoding, err)
-	}
-	return path, nil
-}
-
-// DecodeVersion returns the version string for the given safe encoding.
-// It fails if the encoding is invalid or encodes an invalid version.
-// Versions are allowed to be in non-semver form but must be valid file names
-// and not contain exclamation marks.
-func DecodeVersion(encoding string) (v string, err error) {
-	v, ok := decodeString(encoding)
-	if !ok {
-		return "", fmt.Errorf("invalid version encoding %q", encoding)
-	}
-	if err := checkElem(v, true); err != nil {
-		return "", fmt.Errorf("disallowed version string %q", v)
-	}
-	return v, nil
-}
-
-func decodeString(encoding string) (string, bool) {
-	var buf []byte
-
-	bang := false
-	for _, r := range encoding {
-		if r >= utf8.RuneSelf {
-			return "", false
-		}
-		if bang {
-			bang = false
-			if r < 'a' || 'z' < r {
-				return "", false
-			}
-			buf = append(buf, byte(r+'A'-'a'))
-			continue
-		}
-		if r == '!' {
-			bang = true
-			continue
-		}
-		if 'A' <= r && r <= 'Z' {
-			return "", false
-		}
-		buf = append(buf, byte(r))
-	}
-	if bang {
-		return "", false
-	}
-	return string(buf), true
-}

vendor/golang.org/x/tools/internal/semver/semver.go

@@ -1,388 +0,0 @@
-// Copyright 2018 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-// Package semver implements comparison of semantic version strings.
-// In this package, semantic version strings must begin with a leading "v",
-// as in "v1.0.0".
-//
-// The general form of a semantic version string accepted by this package is
-//
-//	vMAJOR[.MINOR[.PATCH[-PRERELEASE][+BUILD]]]
-//
-// where square brackets indicate optional parts of the syntax;
-// MAJOR, MINOR, and PATCH are decimal integers without extra leading zeros;
-// PRERELEASE and BUILD are each a series of non-empty dot-separated identifiers
-// using only alphanumeric characters and hyphens; and
-// all-numeric PRERELEASE identifiers must not have leading zeros.
-//
-// This package follows Semantic Versioning 2.0.0 (see semver.org)
-// with two exceptions. First, it requires the "v" prefix. Second, it recognizes
-// vMAJOR and vMAJOR.MINOR (with no prerelease or build suffixes)
-// as shorthands for vMAJOR.0.0 and vMAJOR.MINOR.0.
-package semver
-
-// parsed returns the parsed form of a semantic version string.
-type parsed struct {
-	major      string
-	minor      string
-	patch      string
-	short      string
-	prerelease string
-	build      string
-	err        string
-}
-
-// IsValid reports whether v is a valid semantic version string.
-func IsValid(v string) bool {
-	_, ok := parse(v)
-	return ok
-}
-
-// Canonical returns the canonical formatting of the semantic version v.
-// It fills in any missing .MINOR or .PATCH and discards build metadata.
-// Two semantic versions compare equal only if their canonical formattings
-// are identical strings.
-// The canonical invalid semantic version is the empty string.
-func Canonical(v string) string {
-	p, ok := parse(v)
-	if !ok {
-		return ""
-	}
-	if p.build != "" {
-		return v[:len(v)-len(p.build)]
-	}
-	if p.short != "" {
-		return v + p.short
-	}
-	return v
-}
-
-// Major returns the major version prefix of the semantic version v.
-// For example, Major("v2.1.0") == "v2".
-// If v is an invalid semantic version string, Major returns the empty string.
-func Major(v string) string {
-	pv, ok := parse(v)
-	if !ok {
-		return ""
-	}
-	return v[:1+len(pv.major)]
-}
-
-// MajorMinor returns the major.minor version prefix of the semantic version v.
-// For example, MajorMinor("v2.1.0") == "v2.1".
-// If v is an invalid semantic version string, MajorMinor returns the empty string.
-func MajorMinor(v string) string {
-	pv, ok := parse(v)
-	if !ok {
-		return ""
-	}
-	i := 1 + len(pv.major)
-	if j := i + 1 + len(pv.minor); j <= len(v) && v[i] == '.' && v[i+1:j] == pv.minor {
-		return v[:j]
-	}
-	return v[:i] + "." + pv.minor
-}
-
-// Prerelease returns the prerelease suffix of the semantic version v.
-// For example, Prerelease("v2.1.0-pre+meta") == "-pre".
-// If v is an invalid semantic version string, Prerelease returns the empty string.
-func Prerelease(v string) string {
-	pv, ok := parse(v)
-	if !ok {
-		return ""
-	}
-	return pv.prerelease
-}
-
-// Build returns the build suffix of the semantic version v.
-// For example, Build("v2.1.0+meta") == "+meta".
-// If v is an invalid semantic version string, Build returns the empty string.
-func Build(v string) string {
-	pv, ok := parse(v)
-	if !ok {
-		return ""
-	}
-	return pv.build
-}
-
-// Compare returns an integer comparing two versions according to
-// according to semantic version precedence.
-// The result will be 0 if v == w, -1 if v < w, or +1 if v > w.
-//
-// An invalid semantic version string is considered less than a valid one.
-// All invalid semantic version strings compare equal to each other.
-func Compare(v, w string) int {
-	pv, ok1 := parse(v)
-	pw, ok2 := parse(w)
-	if !ok1 && !ok2 {
-		return 0
-	}
-	if !ok1 {
-		return -1
-	}
-	if !ok2 {
-		return +1
-	}
-	if c := compareInt(pv.major, pw.major); c != 0 {
-		return c
-	}
-	if c := compareInt(pv.minor, pw.minor); c != 0 {
-		return c
-	}
-	if c := compareInt(pv.patch, pw.patch); c != 0 {
-		return c
-	}
-	return comparePrerelease(pv.prerelease, pw.prerelease)
-}
-
-// Max canonicalizes its arguments and then returns the version string
-// that compares greater.
-func Max(v, w string) string {
-	v = Canonical(v)
-	w = Canonical(w)
-	if Compare(v, w) > 0 {
-		return v
-	}
-	return w
-}
-
-func parse(v string) (p parsed, ok bool) {
-	if v == "" || v[0] != 'v' {
-		p.err = "missing v prefix"
-		return
-	}
-	p.major, v, ok = parseInt(v[1:])
-	if !ok {
-		p.err = "bad major version"
-		return
-	}
-	if v == "" {
-		p.minor = "0"
-		p.patch = "0"
-		p.short = ".0.0"
-		return
-	}
-	if v[0] != '.' {
-		p.err = "bad minor prefix"
-		ok = false
-		return
-	}
-	p.minor, v, ok = parseInt(v[1:])
-	if !ok {
-		p.err = "bad minor version"
-		return
-	}
-	if v == "" {
-		p.patch = "0"
-		p.short = ".0"
-		return
-	}
-	if v[0] != '.' {
-		p.err = "bad patch prefix"
-		ok = false
-		return
-	}
-	p.patch, v, ok = parseInt(v[1:])
-	if !ok {
-		p.err = "bad patch version"
-		return
-	}
-	if len(v) > 0 && v[0] == '-' {
-		p.prerelease, v, ok = parsePrerelease(v)
-		if !ok {
-			p.err = "bad prerelease"
-			return
-		}
-	}
-	if len(v) > 0 && v[0] == '+' {
-		p.build, v, ok = parseBuild(v)
-		if !ok {
-			p.err = "bad build"
-			return
-		}
-	}
-	if v != "" {
-		p.err = "junk on end"
-		ok = false
-		return
-	}
-	ok = true
-	return
-}
-
-func parseInt(v string) (t, rest string, ok bool) {
-	if v == "" {
-		return
-	}
-	if v[0] < '0' || '9' < v[0] {
-		return
-	}
-	i := 1
-	for i < len(v) && '0' <= v[i] && v[i] <= '9' {
-		i++
-	}
-	if v[0] == '0' && i != 1 {
-		return
-	}
-	return v[:i], v[i:], true
-}
-
-func parsePrerelease(v string) (t, rest string, ok bool) {
-	// "A pre-release version MAY be denoted by appending a hyphen and
-	// a series of dot separated identifiers immediately following the patch version.
-	// Identifiers MUST comprise only ASCII alphanumerics and hyphen [0-9A-Za-z-].
-	// Identifiers MUST NOT be empty. Numeric identifiers MUST NOT include leading zeroes."
-	if v == "" || v[0] != '-' {
-		return
-	}
-	i := 1
-	start := 1
-	for i < len(v) && v[i] != '+' {
-		if !isIdentChar(v[i]) && v[i] != '.' {
-			return
-		}
-		if v[i] == '.' {
-			if start == i || isBadNum(v[start:i]) {
-				return
-			}
-			start = i + 1
-		}
-		i++
-	}
-	if start == i || isBadNum(v[start:i]) {
-		return
-	}
-	return v[:i], v[i:], true
-}
-
-func parseBuild(v string) (t, rest string, ok bool) {
-	if v == "" || v[0] != '+' {
-		return
-	}
-	i := 1
-	start := 1
-	for i < len(v) {
-		if !isIdentChar(v[i]) {
-			return
-		}
-		if v[i] == '.' {
-			if start == i {
-				return
-			}
-			start = i + 1
-		}
-		i++
-	}
-	if start == i {
-		return
-	}
-	return v[:i], v[i:], true
-}
-
-func isIdentChar(c byte) bool {
-	return 'A' <= c && c <= 'Z' || 'a' <= c && c <= 'z' || '0' <= c && c <= '9' || c == '-'
-}
-
-func isBadNum(v string) bool {
-	i := 0
-	for i < len(v) && '0' <= v[i] && v[i] <= '9' {
-		i++
-	}
-	return i == len(v) && i > 1 && v[0] == '0'
-}
-
-func isNum(v string) bool {
-	i := 0
-	for i < len(v) && '0' <= v[i] && v[i] <= '9' {
-		i++
-	}
-	return i == len(v)
-}
-
-func compareInt(x, y string) int {
-	if x == y {
-		return 0
-	}
-	if len(x) < len(y) {
-		return -1
-	}
-	if len(x) > len(y) {
-		return +1
-	}
-	if x < y {
-		return -1
-	} else {
-		return +1
-	}
-}
-
-func comparePrerelease(x, y string) int {
-	// "When major, minor, and patch are equal, a pre-release version has
-	// lower precedence than a normal version.
-	// Example: 1.0.0-alpha < 1.0.0.
-	// Precedence for two pre-release versions with the same major, minor,
-	// and patch version MUST be determined by comparing each dot separated
-	// identifier from left to right until a difference is found as follows:
-	// identifiers consisting of only digits are compared numerically and
-	// identifiers with letters or hyphens are compared lexically in ASCII
-	// sort order. Numeric identifiers always have lower precedence than
-	// non-numeric identifiers. A larger set of pre-release fields has a
-	// higher precedence than a smaller set, if all of the preceding
-	// identifiers are equal.
-	// Example: 1.0.0-alpha < 1.0.0-alpha.1 < 1.0.0-alpha.beta <
-	// 1.0.0-beta < 1.0.0-beta.2 < 1.0.0-beta.11 < 1.0.0-rc.1 < 1.0.0."
-	if x == y {
-		return 0
-	}
-	if x == "" {
-		return +1
-	}
-	if y == "" {
-		return -1
-	}
-	for x != "" && y != "" {
-		x = x[1:] // skip - or .
-		y = y[1:] // skip - or .
-		var dx, dy string
-		dx, x = nextIdent(x)
-		dy, y = nextIdent(y)
-		if dx != dy {
-			ix := isNum(dx)
-			iy := isNum(dy)
-			if ix != iy {
-				if ix {
-					return -1
-				} else {
-					return +1
-				}
-			}
-			if ix {
-				if len(dx) < len(dy) {
-					return -1
-				}
-				if len(dx) > len(dy) {
-					return +1
-				}
-			}
-			if dx < dy {
-				return -1
-			} else {
-				return +1
-			}
-		}
-	}
-	if x == "" {
-		return -1
-	} else {
-		return +1
-	}
-}
-
-func nextIdent(x string) (dx, rest string) {
-	i := 0
-	for i < len(x) && x[i] != '.' {
-		i++
-	}
-	return x[:i], x[i:]
-}