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/k8s.io/kube-openapi/pkg/generators/api_linter.go

@@ -28,7 +28,7 @@ import (
 
 	"k8s.io/gengo/generator"
 	"k8s.io/gengo/types"
-	"k8s.io/klog"
+	"k8s.io/klog/v2"
 )
 
 const apiViolationFileType = "api-violation"
@@ -139,6 +139,7 @@ func newAPILinter() *apiLinter {
 		rules: []APIRule{
 			&rules.NamesMatch{},
 			&rules.OmitEmptyMatchCase{},
+			&rules.ListTypeMissing{},
 		},
 	}
 }

vendor/k8s.io/kube-openapi/pkg/generators/config.go

@@ -24,7 +24,7 @@ import (
 	"k8s.io/gengo/generator"
 	"k8s.io/gengo/namer"
 	"k8s.io/gengo/types"
-	"k8s.io/klog"
+	"k8s.io/klog/v2"
 
 	generatorargs "k8s.io/kube-openapi/cmd/openapi-gen/args"
 )

vendor/k8s.io/kube-openapi/pkg/generators/extension.go

@@ -32,6 +32,7 @@ type extensionAttributes struct {
 	xName         string
 	kind          types.Kind
 	allowedValues sets.String
+	enforceArray  bool
 }
 
 // Extension tag to openapi extension attributes
@@ -46,14 +47,25 @@ var tagToExtension = map[string]extensionAttributes{
 		allowedValues: sets.NewString("merge", "retainKeys"),
 	},
 	"listMapKey": {
-		xName: "x-kubernetes-list-map-keys",
-		kind:  types.Slice,
+		xName:        "x-kubernetes-list-map-keys",
+		kind:         types.Slice,
+		enforceArray: true,
 	},
 	"listType": {
 		xName:         "x-kubernetes-list-type",
 		kind:          types.Slice,
 		allowedValues: sets.NewString("atomic", "set", "map"),
 	},
+	"mapType": {
+		xName:         "x-kubernetes-map-type",
+		kind:          types.Map,
+		allowedValues: sets.NewString("atomic", "granular"),
+	},
+	"structType": {
+		xName:         "x-kubernetes-map-type",
+		kind:          types.Struct,
+		allowedValues: sets.NewString("atomic", "granular"),
+	},
 }
 
 // Extension encapsulates information necessary to generate an OpenAPI extension.
@@ -113,6 +125,10 @@ func (e extension) hasMultipleValues() bool {
 	return len(e.values) > 1
 }
 
+func (e extension) isAlwaysArrayFormat() bool {
+	return tagToExtension[e.idlTag].enforceArray
+}
+
 // Returns sorted list of map keys. Needed for deterministic testing.
 func sortedMapKeys(m map[string][]string) []string {
 	keys := make([]string, len(m))

vendor/k8s.io/kube-openapi/pkg/generators/openapi.go

@@ -18,6 +18,7 @@ package generators
 
 import (
 	"bytes"
+	"encoding/json"
 	"fmt"
 	"io"
 	"path/filepath"
@@ -30,12 +31,13 @@ import (
 	"k8s.io/gengo/types"
 	openapi "k8s.io/kube-openapi/pkg/common"
 
-	"k8s.io/klog"
+	"k8s.io/klog/v2"
 )
 
 // This is the comment tag that carries parameters for open API generation.
 const tagName = "k8s:openapi-gen"
 const tagOptional = "optional"
+const tagDefault = "default"
 
 // Known values for the tag.
 const (
@@ -242,6 +244,16 @@ func methodReturnsValue(mt *types.Type, pkg, name string) bool {
 	return r.Name.Name == name && r.Name.Package == pkg
 }
 
+func hasOpenAPIV3DefinitionMethod(t *types.Type) bool {
+	for mn, mt := range t.Methods {
+		if mn != "OpenAPIV3Definition" {
+			continue
+		}
+		return methodReturnsValue(mt, openAPICommonPackagePath, "OpenAPIDefinition")
+	}
+	return false
+}
+
 func hasOpenAPIDefinitionMethod(t *types.Type) bool {
 	for mn, mt := range t.Methods {
 		if mn != "OpenAPIDefinition" {
@@ -272,6 +284,9 @@ func typeShortName(t *types.Type) string {
 
 func (g openAPITypeWriter) generateMembers(t *types.Type, required []string) ([]string, error) {
 	var err error
+	for t.Kind == types.Pointer { // fast-forward to effective type containing members
+		t = t.Elem
+	}
 	for _, m := range t.Members {
 		if hasOpenAPITagValue(m.CommentLines, tagValueFalse) {
 			continue
@@ -304,9 +319,21 @@ func (g openAPITypeWriter) generateCall(t *types.Type) error {
 	case types.Struct:
 		args := argsFromType(t)
 		g.Do("\"$.$\": ", t.Name)
-		if hasOpenAPIDefinitionMethod(t) {
+
+		hasV2Definition := hasOpenAPIDefinitionMethod(t)
+		hasV2DefinitionTypeAndFormat := hasOpenAPIDefinitionMethods(t)
+		hasV3Definition := hasOpenAPIV3DefinitionMethod(t)
+
+		switch {
+		case hasV2DefinitionTypeAndFormat:
+			g.Do(nameTmpl+"(ref),\n", args)
+		case hasV2Definition && hasV3Definition:
+			g.Do("common.EmbedOpenAPIDefinitionIntoV2Extension($.type|raw${}.OpenAPIV3Definition(), $.type|raw${}.OpenAPIDefinition()),\n", args)
+		case hasV2Definition:
 			g.Do("$.type|raw${}.OpenAPIDefinition(),\n", args)
-		} else {
+		case hasV3Definition:
+			g.Do("$.type|raw${}.OpenAPIV3Definition(),\n", args)
+		default:
 			g.Do(nameTmpl+"(ref),\n", args)
 		}
 	}
@@ -317,14 +344,30 @@ func (g openAPITypeWriter) generate(t *types.Type) error {
 	// Only generate for struct type and ignore the rest
 	switch t.Kind {
 	case types.Struct:
-		if hasOpenAPIDefinitionMethod(t) {
+		hasV2Definition := hasOpenAPIDefinitionMethod(t)
+		hasV2DefinitionTypeAndFormat := hasOpenAPIDefinitionMethods(t)
+		hasV3Definition := hasOpenAPIV3DefinitionMethod(t)
+
+		if hasV2Definition || (hasV3Definition && !hasV2DefinitionTypeAndFormat) {
 			// already invoked directly
 			return nil
 		}
 
 		args := argsFromType(t)
 		g.Do("func "+nameTmpl+"(ref $.ReferenceCallback|raw$) $.OpenAPIDefinition|raw$ {\n", args)
-		if hasOpenAPIDefinitionMethods(t) {
+		switch {
+		case hasV2DefinitionTypeAndFormat && hasV3Definition:
+			g.Do("return common.EmbedOpenAPIDefinitionIntoV2Extension($.type|raw${}.OpenAPIV3Definition(), $.OpenAPIDefinition|raw${\n"+
+				"Schema: spec.Schema{\n"+
+				"SchemaProps: spec.SchemaProps{\n", args)
+			g.generateDescription(t.CommentLines)
+			g.Do("Type:$.type|raw${}.OpenAPISchemaType(),\n"+
+				"Format:$.type|raw${}.OpenAPISchemaFormat(),\n"+
+				"},\n"+
+				"},\n"+
+				"})\n}\n\n", args)
+			return nil
+		case hasV2DefinitionTypeAndFormat:
 			g.Do("return $.OpenAPIDefinition|raw${\n"+
 				"Schema: spec.Schema{\n"+
 				"SchemaProps: spec.SchemaProps{\n", args)
@@ -373,7 +416,7 @@ func (g openAPITypeWriter) generate(t *types.Type) error {
 		deps := []string{}
 		for _, k := range keys {
 			v := g.refTypes[k]
-			if t, _ := openapi.GetOpenAPITypeFormat(v.String()); t != "" {
+			if t, _ := openapi.OpenAPITypeFormat(v.String()); t != "" {
 				// This is a known type, we do not need a reference to it
 				// Will eliminate special case of time.Time
 				continue
@@ -397,11 +440,18 @@ func (g openAPITypeWriter) generateStructExtensions(t *types.Type) error {
 	// Initially, we will only log struct extension errors.
 	if len(errors) > 0 {
 		for _, e := range errors {
-			klog.V(2).Infof("[%s]: %s\n", t.String(), e)
+			klog.Errorf("[%s]: %s\n", t.String(), e)
 		}
 	}
+	unions, errors := parseUnions(t)
+	if len(errors) > 0 {
+		for _, e := range errors {
+			klog.Errorf("[%s]: %s\n", t.String(), e)
+		}
+	}
+
 	// TODO(seans3): Validate struct extensions here.
-	g.emitExtensions(extensions)
+	g.emitExtensions(extensions, unions)
 	return nil
 }
 
@@ -416,28 +466,35 @@ func (g openAPITypeWriter) generateMemberExtensions(m *types.Member, parent *typ
 			klog.V(2).Infof("%s %s\n", errorPrefix, e)
 		}
 	}
-	g.emitExtensions(extensions)
+	g.emitExtensions(extensions, nil)
 	return nil
 }
 
-func (g openAPITypeWriter) emitExtensions(extensions []extension) {
+func (g openAPITypeWriter) emitExtensions(extensions []extension, unions []union) {
 	// If any extensions exist, then emit code to create them.
-	if len(extensions) == 0 {
+	if len(extensions) == 0 && len(unions) == 0 {
 		return
 	}
 	g.Do("VendorExtensible: spec.VendorExtensible{\nExtensions: spec.Extensions{\n", nil)
 	for _, extension := range extensions {
 		g.Do("\"$.$\": ", extension.xName)
-		if extension.hasMultipleValues() {
+		if extension.hasMultipleValues() || extension.isAlwaysArrayFormat() {
 			g.Do("[]interface{}{\n", nil)
 		}
 		for _, value := range extension.values {
 			g.Do("\"$.$\",\n", value)
 		}
-		if extension.hasMultipleValues() {
+		if extension.hasMultipleValues() || extension.isAlwaysArrayFormat() {
 			g.Do("},\n", nil)
 		}
 	}
+	if len(unions) > 0 {
+		g.Do("\"x-kubernetes-unions\": []interface{}{\n", nil)
+		for _, u := range unions {
+			u.emit(g)
+		}
+		g.Do("},\n", nil)
+	}
 	g.Do("},\n},\n", nil)
 }
 
@@ -458,6 +515,60 @@ func (g openAPITypeWriter) validatePatchTags(m *types.Member, parent *types.Type
 	return nil
 }
 
+func defaultFromComments(comments []string) (interface{}, error) {
+	tag, err := getSingleTagsValue(comments, tagDefault)
+	if tag == "" {
+		return nil, err
+	}
+	var i interface{}
+	if err := json.Unmarshal([]byte(tag), &i); err != nil {
+		return nil, fmt.Errorf("failed to unmarshal default: %v", err)
+	}
+	return i, nil
+}
+
+func mustEnforceDefault(t *types.Type, omitEmpty bool) (interface{}, error) {
+	switch t.Kind {
+	case types.Pointer, types.Map, types.Slice, types.Array, types.Interface:
+		return nil, nil
+	case types.Struct:
+		return map[string]interface{}{}, nil
+	case types.Builtin:
+		if !omitEmpty {
+			if zero, ok := openapi.OpenAPIZeroValue(t.String()); ok {
+				return zero, nil
+			} else {
+				return nil, fmt.Errorf("please add type %v to getOpenAPITypeFormat function", t)
+			}
+		}
+		return nil, nil
+	default:
+		return nil, fmt.Errorf("not sure how to enforce default for %v", t.Kind)
+	}
+}
+
+func (g openAPITypeWriter) generateDefault(comments []string, t *types.Type, omitEmpty bool) error {
+	t = resolveAliasType(t)
+	def, err := defaultFromComments(comments)
+	if err != nil {
+		return err
+	}
+	if enforced, err := mustEnforceDefault(t, omitEmpty); err != nil {
+		return err
+	} else if enforced != nil {
+		if def == nil {
+			def = enforced
+		} else if !reflect.DeepEqual(def, enforced) {
+			enforcedJson, _ := json.Marshal(enforced)
+			return fmt.Errorf("invalid default value (%#v) for non-pointer/non-omitempty. If specified, must be: %v", def, string(enforcedJson))
+		}
+	}
+	if def != nil {
+		g.Do("Default: $.$,\n", fmt.Sprintf("%#v", def))
+	}
+	return nil
+}
+
 func (g openAPITypeWriter) generateDescription(CommentLines []string) {
 	var buffer bytes.Buffer
 	delPrevChar := func() {
@@ -482,7 +593,7 @@ func (g openAPITypeWriter) generateDescription(CommentLines []string) {
 		default:
 			if strings.HasPrefix(line, " ") || strings.HasPrefix(line, "\t") {
 				delPrevChar()
-				line = "\n" + line + "\n" // Replace it with newline. This is useful when we have a line with: "Example:\n\tJSON-someting..."
+				line = "\n" + line + "\n" // Replace it with newline. This is useful when we have a line with: "Example:\n\tJSON-something..."
 			} else {
 				line += " "
 			}
@@ -521,9 +632,13 @@ func (g openAPITypeWriter) generateProperty(m *types.Member, parent *types.Type)
 		g.Do("},\n},\n", nil)
 		return nil
 	}
+	omitEmpty := strings.Contains(reflect.StructTag(m.Tags).Get("json"), "omitempty")
+	if err := g.generateDefault(m.CommentLines, m.Type, omitEmpty); err != nil {
+		return fmt.Errorf("failed to generate default in %v: %v: %v", parent, m.Name, err)
+	}
 	t := resolveAliasAndPtrType(m.Type)
 	// If we can get a openAPI type and format for this type, we consider it to be simple property
-	typeString, format := openapi.GetOpenAPITypeFormat(t.String())
+	typeString, format := openapi.OpenAPITypeFormat(t.String())
 	if typeString != "" {
 		g.generateSimpleProperty(typeString, format)
 		g.Do("},\n},\n", nil)
@@ -534,11 +649,11 @@ func (g openAPITypeWriter) generateProperty(m *types.Member, parent *types.Type)
 		return fmt.Errorf("please add type %v to getOpenAPITypeFormat function", t)
 	case types.Map:
 		if err := g.generateMapProperty(t); err != nil {
-			return err
+			return fmt.Errorf("failed to generate map property in %v: %v: %v", parent, m.Name, err)
 		}
 	case types.Slice, types.Array:
 		if err := g.generateSliceProperty(t); err != nil {
-			return err
+			return fmt.Errorf("failed to generate slice property in %v: %v: %v", parent, m.Name, err)
 		}
 	case types.Struct, types.Interface:
 		g.generateReferenceProperty(t)
@@ -559,6 +674,17 @@ func (g openAPITypeWriter) generateReferenceProperty(t *types.Type) {
 	g.Do("Ref: ref(\"$.$\"),\n", t.Name.String())
 }
 
+func resolveAliasType(t *types.Type) *types.Type {
+	var prev *types.Type
+	for prev != t {
+		prev = t
+		if t.Kind == types.Alias {
+			t = t.Underlying
+		}
+	}
+	return t
+}
+
 func resolveAliasAndPtrType(t *types.Type) *types.Type {
 	var prev *types.Type
 	for prev != t {
@@ -581,9 +707,13 @@ func (g openAPITypeWriter) generateMapProperty(t *types.Type) error {
 	if keyType.Name.Name != "string" {
 		return fmt.Errorf("map with non-string keys are not supported by OpenAPI in %v", t)
 	}
+
 	g.Do("Type: []string{\"object\"},\n", nil)
 	g.Do("AdditionalProperties: &spec.SchemaOrBool{\nAllows: true,\nSchema: &spec.Schema{\nSchemaProps: spec.SchemaProps{\n", nil)
-	typeString, format := openapi.GetOpenAPITypeFormat(elemType.String())
+	if err := g.generateDefault(t.Elem.CommentLines, t.Elem, false); err != nil {
+		return err
+	}
+	typeString, format := openapi.OpenAPITypeFormat(elemType.String())
 	if typeString != "" {
 		g.generateSimpleProperty(typeString, format)
 		g.Do("},\n},\n},\n", nil)
@@ -595,7 +725,13 @@ func (g openAPITypeWriter) generateMapProperty(t *types.Type) error {
 	case types.Struct:
 		g.generateReferenceProperty(elemType)
 	case types.Slice, types.Array:
-		g.generateSliceProperty(elemType)
+		if err := g.generateSliceProperty(elemType); err != nil {
+			return err
+		}
+	case types.Map:
+		if err := g.generateMapProperty(elemType); err != nil {
+			return err
+		}
 	default:
 		return fmt.Errorf("map Element kind %v is not supported in %v", elemType.Kind, t.Name)
 	}
@@ -607,7 +743,10 @@ func (g openAPITypeWriter) generateSliceProperty(t *types.Type) error {
 	elemType := resolveAliasAndPtrType(t.Elem)
 	g.Do("Type: []string{\"array\"},\n", nil)
 	g.Do("Items: &spec.SchemaOrArray{\nSchema: &spec.Schema{\nSchemaProps: spec.SchemaProps{\n", nil)
-	typeString, format := openapi.GetOpenAPITypeFormat(elemType.String())
+	if err := g.generateDefault(t.Elem.CommentLines, t.Elem, false); err != nil {
+		return err
+	}
+	typeString, format := openapi.OpenAPITypeFormat(elemType.String())
 	if typeString != "" {
 		g.generateSimpleProperty(typeString, format)
 		g.Do("},\n},\n},\n", nil)
@@ -619,7 +758,13 @@ func (g openAPITypeWriter) generateSliceProperty(t *types.Type) error {
 	case types.Struct:
 		g.generateReferenceProperty(elemType)
 	case types.Slice, types.Array:
-		g.generateSliceProperty(elemType)
+		if err := g.generateSliceProperty(elemType); err != nil {
+			return err
+		}
+	case types.Map:
+		if err := g.generateMapProperty(elemType); err != nil {
+			return err
+		}
 	default:
 		return fmt.Errorf("slice Element kind %v is not supported in %v", elemType.Kind, t)
 	}

vendor/k8s.io/kube-openapi/pkg/generators/rules/idl_tag.go

@@ -0,0 +1,53 @@
+package rules
+
+import (
+	"k8s.io/gengo/types"
+)
+
+const ListTypeIDLTag = "listType"
+
+// ListTypeMissing implements APIRule interface.
+// A list type is required for inlined list.
+type ListTypeMissing struct{}
+
+// Name returns the name of APIRule
+func (l *ListTypeMissing) Name() string {
+	return "list_type_missing"
+}
+
+// Validate evaluates API rule on type t and returns a list of field names in
+// the type that violate the rule. Empty field name [""] implies the entire
+// type violates the rule.
+func (l *ListTypeMissing) Validate(t *types.Type) ([]string, error) {
+	fields := make([]string, 0)
+
+	switch t.Kind {
+	case types.Struct:
+		for _, m := range t.Members {
+			hasListType := types.ExtractCommentTags("+", m.CommentLines)[ListTypeIDLTag] != nil
+
+			if m.Name == "Items" && m.Type.Kind == types.Slice && hasNamedMember(t, "ListMeta") {
+				if hasListType {
+					fields = append(fields, m.Name)
+				}
+				continue
+			}
+
+			if m.Type.Kind == types.Slice && !hasListType {
+				fields = append(fields, m.Name)
+				continue
+			}
+		}
+	}
+
+	return fields, nil
+}
+
+func hasNamedMember(t *types.Type, name string) bool {
+	for _, m := range t.Members {
+		if m.Name == name {
+			return true
+		}
+	}
+	return false
+}

vendor/k8s.io/kube-openapi/pkg/generators/rules/names_match.go

@@ -155,7 +155,7 @@ func namesMatch(goName, jsonName string) bool {
 	return true
 }
 
-// isCaptical returns true if one character is capital
+// isCapital returns true if one character is capital
 func isCapital(b byte) bool {
 	return b >= 'A' && b <= 'Z'
 }

vendor/k8s.io/kube-openapi/pkg/generators/union.go

@@ -0,0 +1,207 @@
+/*
+Copyright 2016 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package generators
+
+import (
+	"fmt"
+	"sort"
+
+	"k8s.io/gengo/types"
+)
+
+const tagUnionMember = "union"
+const tagUnionDeprecated = "unionDeprecated"
+const tagUnionDiscriminator = "unionDiscriminator"
+
+type union struct {
+	discriminator         string
+	fieldsToDiscriminated map[string]string
+}
+
+// emit prints the union, can be called on a nil union (emits nothing)
+func (u *union) emit(g openAPITypeWriter) {
+	if u == nil {
+		return
+	}
+	g.Do("map[string]interface{}{\n", nil)
+	if u.discriminator != "" {
+		g.Do("\"discriminator\": \"$.$\",\n", u.discriminator)
+	}
+	g.Do("\"fields-to-discriminateBy\": map[string]interface{}{\n", nil)
+	keys := []string{}
+	for field := range u.fieldsToDiscriminated {
+		keys = append(keys, field)
+	}
+	sort.Strings(keys)
+	for _, field := range keys {
+		g.Do("\"$.$\": ", field)
+		g.Do("\"$.$\",\n", u.fieldsToDiscriminated[field])
+	}
+	g.Do("},\n", nil)
+	g.Do("},\n", nil)
+}
+
+// Sets the discriminator if it's not set yet, otherwise return an error
+func (u *union) setDiscriminator(value string) []error {
+	errors := []error{}
+	if u.discriminator != "" {
+		errors = append(errors, fmt.Errorf("at least two discriminators found: %v and %v", value, u.discriminator))
+	}
+	u.discriminator = value
+	return errors
+}
+
+// Add a new member to the union
+func (u *union) addMember(jsonName, variableName string) {
+	if _, ok := u.fieldsToDiscriminated[jsonName]; ok {
+		panic(fmt.Errorf("same field (%v) found multiple times", jsonName))
+	}
+	u.fieldsToDiscriminated[jsonName] = variableName
+}
+
+// Makes sure that the union is valid, specifically looking for re-used discriminated
+func (u *union) isValid() []error {
+	errors := []error{}
+	// Case 1: discriminator but no fields
+	if u.discriminator != "" && len(u.fieldsToDiscriminated) == 0 {
+		errors = append(errors, fmt.Errorf("discriminator set with no fields in union"))
+	}
+	// Case 2: two fields have the same discriminated value
+	discriminated := map[string]struct{}{}
+	for _, d := range u.fieldsToDiscriminated {
+		if _, ok := discriminated[d]; ok {
+			errors = append(errors, fmt.Errorf("discriminated value is used twice: %v", d))
+		}
+		discriminated[d] = struct{}{}
+	}
+	// Case 3: a field is both discriminator AND part of the union
+	if u.discriminator != "" {
+		if _, ok := u.fieldsToDiscriminated[u.discriminator]; ok {
+			errors = append(errors, fmt.Errorf("%v can't be both discriminator and part of the union", u.discriminator))
+		}
+	}
+	return errors
+}
+
+// Find unions either directly on the members (or inlined members, not
+// going across types) or on the type itself, or on embedded types.
+func parseUnions(t *types.Type) ([]union, []error) {
+	errors := []error{}
+	unions := []union{}
+	su, err := parseUnionStruct(t)
+	if su != nil {
+		unions = append(unions, *su)
+	}
+	errors = append(errors, err...)
+	eu, err := parseEmbeddedUnion(t)
+	unions = append(unions, eu...)
+	errors = append(errors, err...)
+	mu, err := parseUnionMembers(t)
+	if mu != nil {
+		unions = append(unions, *mu)
+	}
+	errors = append(errors, err...)
+	return unions, errors
+}
+
+// Find unions in embedded types, unions shouldn't go across types.
+func parseEmbeddedUnion(t *types.Type) ([]union, []error) {
+	errors := []error{}
+	unions := []union{}
+	for _, m := range t.Members {
+		if hasOpenAPITagValue(m.CommentLines, tagValueFalse) {
+			continue
+		}
+		if !shouldInlineMembers(&m) {
+			continue
+		}
+		u, err := parseUnions(m.Type)
+		unions = append(unions, u...)
+		errors = append(errors, err...)
+	}
+	return unions, errors
+}
+
+// Look for union tag on a struct, and then include all the fields
+// (except the discriminator if there is one). The struct shouldn't have
+// embedded types.
+func parseUnionStruct(t *types.Type) (*union, []error) {
+	errors := []error{}
+	if types.ExtractCommentTags("+", t.CommentLines)[tagUnionMember] == nil {
+		return nil, nil
+	}
+
+	u := &union{fieldsToDiscriminated: map[string]string{}}
+
+	for _, m := range t.Members {
+		jsonName := getReferableName(&m)
+		if jsonName == "" {
+			continue
+		}
+		if shouldInlineMembers(&m) {
+			errors = append(errors, fmt.Errorf("union structures can't have embedded fields: %v.%v", t.Name, m.Name))
+			continue
+		}
+		if types.ExtractCommentTags("+", m.CommentLines)[tagUnionDeprecated] != nil {
+			errors = append(errors, fmt.Errorf("union struct can't have unionDeprecated members: %v.%v", t.Name, m.Name))
+			continue
+		}
+		if types.ExtractCommentTags("+", m.CommentLines)[tagUnionDiscriminator] != nil {
+			errors = append(errors, u.setDiscriminator(jsonName)...)
+		} else {
+			if !hasOptionalTag(&m) {
+				errors = append(errors, fmt.Errorf("union members must be optional: %v.%v", t.Name, m.Name))
+			}
+			u.addMember(jsonName, m.Name)
+		}
+	}
+
+	return u, errors
+}
+
+// Find unions specifically on members.
+func parseUnionMembers(t *types.Type) (*union, []error) {
+	errors := []error{}
+	u := &union{fieldsToDiscriminated: map[string]string{}}
+
+	for _, m := range t.Members {
+		jsonName := getReferableName(&m)
+		if jsonName == "" {
+			continue
+		}
+		if shouldInlineMembers(&m) {
+			continue
+		}
+		if types.ExtractCommentTags("+", m.CommentLines)[tagUnionDiscriminator] != nil {
+			errors = append(errors, u.setDiscriminator(jsonName)...)
+		}
+		if types.ExtractCommentTags("+", m.CommentLines)[tagUnionMember] != nil {
+			errors = append(errors, fmt.Errorf("union tag is not accepted on struct members: %v.%v", t.Name, m.Name))
+			continue
+		}
+		if types.ExtractCommentTags("+", m.CommentLines)[tagUnionDeprecated] != nil {
+			if !hasOptionalTag(&m) {
+				errors = append(errors, fmt.Errorf("union members must be optional: %v.%v", t.Name, m.Name))
+			}
+			u.addMember(jsonName, m.Name)
+		}
+	}
+	if len(u.fieldsToDiscriminated) == 0 {
+		return nil, nil
+	}
+	return u, append(errors, u.isValid()...)
+}