staticcheck (#313)

* CI: use staticcheck for linting

This commit switches the linter for Go code from golint to staticcheck.
Golint has been deprecated since last year and staticcheck is a
recommended replacement.

Signed-off-by: Lucas Servén Marín <lserven@gmail.com>

* revendor

Signed-off-by: Lucas Servén Marín <lserven@gmail.com>

* cmd,pkg: fix lint warnings

Signed-off-by: Lucas Servén Marín <lserven@gmail.com>

vendor/github.com/BurntSushi/toml/decode_meta.go

@@ -0,0 +1,123 @@
+package toml
+
+import "strings"
+
+// MetaData allows access to meta information about TOML data that may not be
+// inferable via reflection. In particular, whether a key has been defined and
+// the TOML type of a key.
+type MetaData struct {
+	mapping map[string]interface{}
+	types   map[string]tomlType
+	keys    []Key
+	decoded map[string]bool
+	context Key // Used only during decoding.
+}
+
+// IsDefined reports if the key exists in the TOML data.
+//
+// The key should be specified hierarchically, for example to access the TOML
+// key "a.b.c" you would use:
+//
+//	IsDefined("a", "b", "c")
+//
+// IsDefined will return false if an empty key given. Keys are case sensitive.
+func (md *MetaData) IsDefined(key ...string) bool {
+	if len(key) == 0 {
+		return false
+	}
+
+	var hash map[string]interface{}
+	var ok bool
+	var hashOrVal interface{} = md.mapping
+	for _, k := range key {
+		if hash, ok = hashOrVal.(map[string]interface{}); !ok {
+			return false
+		}
+		if hashOrVal, ok = hash[k]; !ok {
+			return false
+		}
+	}
+	return true
+}
+
+// Type returns a string representation of the type of the key specified.
+//
+// Type will return the empty string if given an empty key or a key that does
+// not exist. Keys are case sensitive.
+func (md *MetaData) Type(key ...string) string {
+	fullkey := strings.Join(key, ".")
+	if typ, ok := md.types[fullkey]; ok {
+		return typ.typeString()
+	}
+	return ""
+}
+
+// Key represents any TOML key, including key groups. Use (MetaData).Keys to get
+// values of this type.
+type Key []string
+
+func (k Key) String() string { return strings.Join(k, ".") }
+
+func (k Key) maybeQuotedAll() string {
+	var ss []string
+	for i := range k {
+		ss = append(ss, k.maybeQuoted(i))
+	}
+	return strings.Join(ss, ".")
+}
+
+func (k Key) maybeQuoted(i int) string {
+	if k[i] == "" {
+		return `""`
+	}
+	quote := false
+	for _, c := range k[i] {
+		if !isBareKeyChar(c) {
+			quote = true
+			break
+		}
+	}
+	if quote {
+		return `"` + quotedReplacer.Replace(k[i]) + `"`
+	}
+	return k[i]
+}
+
+func (k Key) add(piece string) Key {
+	newKey := make(Key, len(k)+1)
+	copy(newKey, k)
+	newKey[len(k)] = piece
+	return newKey
+}
+
+// Keys returns a slice of every key in the TOML data, including key groups.
+//
+// Each key is itself a slice, where the first element is the top of the
+// hierarchy and the last is the most specific. The list will have the same
+// order as the keys appeared in the TOML data.
+//
+// All keys returned are non-empty.
+func (md *MetaData) Keys() []Key {
+	return md.keys
+}
+
+// Undecoded returns all keys that have not been decoded in the order in which
+// they appear in the original TOML document.
+//
+// This includes keys that haven't been decoded because of a Primitive value.
+// Once the Primitive value is decoded, the keys will be considered decoded.
+//
+// Also note that decoding into an empty interface will result in no decoding,
+// and so no keys will be considered decoded.
+//
+// In this sense, the Undecoded keys correspond to keys in the TOML document
+// that do not have a concrete type in your representation.
+func (md *MetaData) Undecoded() []Key {
+	undecoded := make([]Key, 0, len(md.keys))
+	for _, key := range md.keys {
+		if !md.decoded[key.String()] {
+			undecoded = append(undecoded, key)
+		}
+	}
+	return undecoded
+}