Fixes:

* Fix kubecfg test, which was writing an internal object straight to yaml
* Address review comments

pkg/conversion/converter.go

@@ -40,17 +40,17 @@ type Converter struct {
 	// If non-nil, will be called to print helpful debugging info. Quite verbose.
 	Debug DebugLogger
 
-	// Name is called to retrieve the name of a type; this name is used for the
+	// NameFunc is called to retrieve the name of a type; this name is used for the
 	// purpose of deciding whether two types match or not (i.e., will we attempt to
 	// do a conversion). The default returns the go type name.
-	Name func(t reflect.Type) string
+	NameFunc func(t reflect.Type) string
 }
 
 // NewConverter creates a new Converter object.
 func NewConverter() *Converter {
 	return &Converter{
-		funcs: map[typePair]reflect.Value{},
+		funcs:    map[typePair]reflect.Value{},
-		Name:  func(t reflect.Type) string { return t.Name() },
+		NameFunc: func(t reflect.Type) string { return t.Name() },
 	}
 }
 
@@ -71,62 +71,70 @@ type Scope interface {
 	Flags() FieldMatchingFlags
 
 	// Meta returns any information originally passed to Convert.
-	Meta() map[string]interface{}
+	Meta() *Meta
+}
+
+// Meta is supplied by Scheme, when it calls Convert.
+type Meta struct {
+	SrcVersion  string
+	DestVersion string
+
+	// TODO: If needed, add a user data field here.
 }
 
 // scope contains information about an ongoing conversion.
 type scope struct {
 	converter    *Converter
-	meta         map[string]interface{}
+	meta         *Meta
 	flags        FieldMatchingFlags
 	srcTagStack  []reflect.StructTag
 	destTagStack []reflect.StructTag
 }
 
 // push adds a level to the src/dest tag stacks.
-func (sa *scope) push() {
+func (s *scope) push() {
-	sa.srcTagStack = append(sa.srcTagStack, "")
+	s.srcTagStack = append(s.srcTagStack, "")
-	sa.destTagStack = append(sa.destTagStack, "")
+	s.destTagStack = append(s.destTagStack, "")
 }
 
 // pop removes a level to the src/dest tag stacks.
-func (sa *scope) pop() {
+func (s *scope) pop() {
-	n := len(sa.srcTagStack)
+	n := len(s.srcTagStack)
-	sa.srcTagStack = sa.srcTagStack[:n-1]
+	s.srcTagStack = s.srcTagStack[:n-1]
-	sa.destTagStack = sa.destTagStack[:n-1]
+	s.destTagStack = s.destTagStack[:n-1]
 }
 
-func (sa *scope) setSrcTag(tag reflect.StructTag) {
+func (s *scope) setSrcTag(tag reflect.StructTag) {
-	sa.srcTagStack[len(sa.srcTagStack)-1] = tag
+	s.srcTagStack[len(s.srcTagStack)-1] = tag
 }
 
-func (sa *scope) setDestTag(tag reflect.StructTag) {
+func (s *scope) setDestTag(tag reflect.StructTag) {
-	sa.destTagStack[len(sa.destTagStack)-1] = tag
+	s.destTagStack[len(s.destTagStack)-1] = tag
 }
 
 // Convert continues a conversion.
-func (sa *scope) Convert(src, dest interface{}, flags FieldMatchingFlags) error {
+func (s *scope) Convert(src, dest interface{}, flags FieldMatchingFlags) error {
-	return sa.converter.Convert(src, dest, flags, sa.meta)
+	return s.converter.Convert(src, dest, flags, s.meta)
 }
 
 // SrcTag returns the tag of the struct containing the current source item, if any.
-func (sa *scope) SrcTag() reflect.StructTag {
+func (s *scope) SrcTag() reflect.StructTag {
-	return sa.srcTagStack[len(sa.srcTagStack)-1]
+	return s.srcTagStack[len(s.srcTagStack)-1]
 }
 
 // DestTag returns the tag of the struct containing the current dest item, if any.
-func (sa *scope) DestTag() reflect.StructTag {
+func (s *scope) DestTag() reflect.StructTag {
-	return sa.destTagStack[len(sa.destTagStack)-1]
+	return s.destTagStack[len(s.destTagStack)-1]
 }
 
 // Flags returns the flags with which the current conversion was started.
-func (sa *scope) Flags() FieldMatchingFlags {
+func (s *scope) Flags() FieldMatchingFlags {
-	return sa.flags
+	return s.flags
 }
 
 // Meta returns the meta object that was originally passed to Convert.
-func (sa *scope) Meta() map[string]interface{} {
+func (s *scope) Meta() *Meta {
-	return sa.meta
+	return s.meta
 }
 
 // Register registers a conversion func with the Converter. conversionFunc must take
@@ -202,9 +210,9 @@ func (f FieldMatchingFlags) IsSet(flag FieldMatchingFlags) bool {
 // Read the comments on the various FieldMatchingFlags constants to understand
 // what the 'flags' parameter does.
 // 'meta' is given to allow you to pass information to conversion functions,
-// it is not used by Convert other than storing it in the scope.
+// it is not used by Convert() other than storing it in the scope.
 // Not safe for objects with cyclic references!
-func (c *Converter) Convert(src, dest interface{}, flags FieldMatchingFlags, meta map[string]interface{}) error {
+func (c *Converter) Convert(src, dest interface{}, flags FieldMatchingFlags, meta *Meta) error {
 	dv, sv := reflect.ValueOf(dest), reflect.ValueOf(src)
 	if dv.Kind() != reflect.Ptr {
 		return fmt.Errorf("Need pointer, but got %#v", dest)
@@ -244,7 +252,7 @@ func (c *Converter) convert(sv, dv reflect.Value, scope *scope) error {
 		return ret.(error)
 	}
 
-	if !scope.flags.IsSet(AllowDifferentFieldTypeNames) && c.Name(dt) != c.Name(st) {
+	if !scope.flags.IsSet(AllowDifferentFieldTypeNames) && c.NameFunc(dt) != c.NameFunc(st) {
 		return fmt.Errorf("Can't convert %v to %v because type names don't match.", st, dt)
 	}
 

pkg/conversion/converter_test.go

@@ -103,7 +103,7 @@ func TestConverter_fuzz(t *testing.T) {
 
 	f := fuzz.New().NilChance(.5).NumElements(0, 100)
 	c := NewConverter()
-	c.Name = func(t reflect.Type) string {
+	c.NameFunc = func(t reflect.Type) string {
 		// Hide the fact that we don't have separate packages for these things.
 		return map[reflect.Type]string{
 			reflect.TypeOf(TestType1{}):         "TestType1",
@@ -168,7 +168,7 @@ func TestConverter_meta(t *testing.T) {
 	checks := 0
 	err := c.Register(
 		func(in *Foo, out *Bar, s Scope) error {
-			if s.Meta()["test"] != "passes" {
+			if s.Meta() == nil || s.Meta().SrcVersion != "test" || s.Meta().DestVersion != "passes" {
 				t.Errorf("Meta did not get passed!")
 			}
 			checks++
@@ -181,7 +181,7 @@ func TestConverter_meta(t *testing.T) {
 	}
 	err = c.Register(
 		func(in *string, out *string, s Scope) error {
-			if s.Meta()["test"] != "passes" {
+			if s.Meta() == nil || s.Meta().SrcVersion != "test" || s.Meta().DestVersion != "passes" {
 				t.Errorf("Meta did not get passed a second time!")
 			}
 			checks++
@@ -191,7 +191,7 @@ func TestConverter_meta(t *testing.T) {
 	if err != nil {
 		t.Fatalf("Unexpected error: %v", err)
 	}
-	err = c.Convert(&Foo{}, &Bar{}, 0, map[string]interface{}{"test": "passes"})
+	err = c.Convert(&Foo{}, &Bar{}, 0, &Meta{SrcVersion: "test", DestVersion: "passes"})
 	if err != nil {
 		t.Fatalf("Unexpected error: %v", err)
 	}

pkg/conversion/scheme.go

@@ -86,15 +86,19 @@ func NewScheme() *Scheme {
 		ExternalVersion:      "v1",
 		MetaInsertionFactory: metaInsertion{},
 	}
-	s.converter.Name = func(t reflect.Type) string {
+	s.converter.NameFunc = s.nameFunc
-		if kind, ok := s.typeToKind[t]; ok {
-			return kind
-		}
-		return t.Name()
-	}
 	return s
 }
 
+// nameFunc returns the name of the type that we wish to use for encoding. Defaults to
+// the go name of the type if the type is not registered.
+func (s *Scheme) nameFunc(t reflect.Type) string {
+	if kind, ok := s.typeToKind[t]; ok {
+		return kind
+	}
+	return t.Name()
+}
+
 // AddKnownTypes registers all types passed in 'types' as being members of version 'version.
 // Encode() will refuse objects unless their type has been registered with AddKnownTypes.
 // All objects passed to types should be pointers to structs. The name that go reports for
@@ -161,22 +165,25 @@ func (s *Scheme) NewObject(versionName, typeName string) (interface{}, error) {
 //
 // Note that, if you need to copy sub-objects that didn't change, you can use the
 // conversion.Scope object that will be passed to your conversion function.
-// Additionally, all conversions started by Scheme will set the "srcVersion" and
+// Additionally, all conversions started by Scheme will set the SrcVersion and
-// "destVersion" keys on the meta object. Example:
+// DestVersion fields on the Meta object. Example:
 //
 // s.AddConversionFuncs(
 //	func(in *InternalObject, out *ExternalObject, scope conversion.Scope) error {
-//		// You can depend on this being set to the source version, e.g., "".
+//		// You can depend on Meta() being non-nil, and this being set to
-//		s.Meta()["srcVersion"].(string)
+//		// the source version, e.g., ""
+//		s.Meta().SrcVersion
 //		// You can depend on this being set to the destination version,
 //		// e.g., "v1beta1".
-//		s.Meta()["destVersion"].(string)
+//		s.Meta().DestVersion
 //		// Call scope.Convert to copy sub-fields.
 //		s.Convert(&in.SubFieldThatMoved, &out.NewLocation.NewName, 0)
 //		return nil
 //	},
 // )
 //
+// (For more detail about conversion functions, see Converter.Register's comment.)
+//
 // Also note that the default behavior, if you don't add a conversion function, is to
 // sanely copy fields that have the same names and same type names. It's OK if the
 // destination type has extra fields, but it must not remove any. So you only need to
@@ -196,7 +203,7 @@ func (s *Scheme) AddConversionFuncs(conversionFuncs ...interface{}) error {
 // possible. You can call this with types that haven't been registered (for example,
 // a to test conversion of types that are nested within registered types), but in
 // that case, the conversion.Scope object passed to your conversion functions won't
-// have "srcVersion" or "destVersion" keys set correctly in Meta().
+// have SrcVersion or DestVersion fields set correctly in Meta().
 func (s *Scheme) Convert(in, out interface{}) error {
 	inVersion := "unknown"
 	outVersion := "unknown"
@@ -209,11 +216,11 @@ func (s *Scheme) Convert(in, out interface{}) error {
 	return s.converter.Convert(in, out, 0, s.generateConvertMeta(inVersion, outVersion))
 }
 
-// generateConvertMeta assembles a map for the meta value we pass to Convert.
+// generateConvertMeta constructs the meta value we pass to Convert.
-func (s *Scheme) generateConvertMeta(srcVersion, destVersion string) map[string]interface{} {
+func (s *Scheme) generateConvertMeta(srcVersion, destVersion string) *Meta {
-	return map[string]interface{}{
+	return &Meta{
-		"srcVersion":  srcVersion,
+		SrcVersion:  srcVersion,
-		"destVersion": destVersion,
+		DestVersion: destVersion,
 	}
 }
 

pkg/conversion/scheme_test.go

@@ -293,10 +293,10 @@ func TestMetaValues(t *testing.T) {
 	// Register functions to verify that scope.Meta() gets set correctly.
 	err := s.AddConversionFuncs(
 		func(in *InternalSimple, out *ExternalSimple, scope Scope) error {
-			if e, a := "", scope.Meta()["srcVersion"].(string); e != a {
+			if e, a := "", scope.Meta().SrcVersion; e != a {
 				t.Errorf("Expected '%v', got '%v'", e, a)
 			}
-			if e, a := "externalVersion", scope.Meta()["destVersion"].(string); e != a {
+			if e, a := "externalVersion", scope.Meta().DestVersion; e != a {
 				t.Errorf("Expected '%v', got '%v'", e, a)
 			}
 			scope.Convert(&in.TestString, &out.TestString, 0)
@@ -304,10 +304,10 @@ func TestMetaValues(t *testing.T) {
 			return nil
 		},
 		func(in *ExternalSimple, out *InternalSimple, scope Scope) error {
-			if e, a := "externalVersion", scope.Meta()["srcVersion"].(string); e != a {
+			if e, a := "externalVersion", scope.Meta().SrcVersion; e != a {
 				t.Errorf("Expected '%v', got '%v'", e, a)
 			}
-			if e, a := "", scope.Meta()["destVersion"].(string); e != a {
+			if e, a := "", scope.Meta().DestVersion; e != a {
 				t.Errorf("Expected '%v', got '%v'", e, a)
 			}
 			scope.Convert(&in.TestString, &out.TestString, 0)
@@ -381,10 +381,10 @@ func TestMetaValuesUnregisteredConvert(t *testing.T) {
 	// Register functions to verify that scope.Meta() gets set correctly.
 	err := s.AddConversionFuncs(
 		func(in *InternalSimple, out *ExternalSimple, scope Scope) error {
-			if e, a := "unknown", scope.Meta()["srcVersion"].(string); e != a {
+			if e, a := "unknown", scope.Meta().SrcVersion; e != a {
 				t.Errorf("Expected '%v', got '%v'", e, a)
 			}
-			if e, a := "unknown", scope.Meta()["destVersion"].(string); e != a {
+			if e, a := "unknown", scope.Meta().DestVersion; e != a {
 				t.Errorf("Expected '%v', got '%v'", e, a)
 			}
 			scope.Convert(&in.TestString, &out.TestString, 0)

pkg/kubecfg/parse_test.go

@@ -17,6 +17,7 @@ limitations under the License.
 package kubecfg
 
 import (
+	"encoding/json"
 	"testing"
 
 	"github.com/GoogleCloudPlatform/kubernetes/pkg/api"
@@ -34,7 +35,9 @@ func TestParseBadStorage(t *testing.T) {
 
 func DoParseTest(t *testing.T, storage string, obj runtime.Object, p *Parser) {
 	jsonData, _ := runtime.DefaultCodec.Encode(obj)
-	yamlData, _ := yaml.Marshal(obj)
+	var tmp map[string]interface{}
+	json.Unmarshal(jsonData, &tmp)
+	yamlData, _ := yaml.Marshal(tmp)
 	t.Logf("Intermediate yaml:\n%v\n", string(yamlData))
 	t.Logf("Intermediate json:\n%v\n", string(jsonData))
 	jsonGot, jsonErr := p.ToWireFormat(jsonData, storage, runtime.DefaultCodec)

pkg/runtime/scheme.go

@@ -54,8 +54,8 @@ func GetScheme(schemeName string) *Scheme {
 // from a conversion.Scope.
 func fromScope(s conversion.Scope) (inVersion, outVersion string, scheme *Scheme) {
 	scheme = DefaultScheme
-	inVersion = s.Meta()["srcVersion"].(string)
+	inVersion = s.Meta().SrcVersion
-	outVersion = s.Meta()["destVersion"].(string)
+	outVersion = s.Meta().DestVersion
 	// If a scheme tag was provided, use it. Look at the struct tag corresponding
 	// to version "".
 	if name := s.SrcTag().Get("scheme"); inVersion == "" && name != "" {

pkg/runtime/scheme_test.go

@@ -52,10 +52,10 @@ func TestScheme(t *testing.T) {
 	// Register functions to verify that scope.Meta() gets set correctly.
 	err := runtime.DefaultScheme.AddConversionFuncs(
 		func(in *InternalSimple, out *ExternalSimple, scope conversion.Scope) error {
-			if e, a := "", scope.Meta()["srcVersion"].(string); e != a {
+			if e, a := "", scope.Meta().SrcVersion; e != a {
 				t.Errorf("Expected '%v', got '%v'", e, a)
 			}
-			if e, a := "externalVersion", scope.Meta()["destVersion"].(string); e != a {
+			if e, a := "externalVersion", scope.Meta().DestVersion; e != a {
 				t.Errorf("Expected '%v', got '%v'", e, a)
 			}
 			scope.Convert(&in.JSONBase, &out.JSONBase, 0)
@@ -64,10 +64,10 @@ func TestScheme(t *testing.T) {
 			return nil
 		},
 		func(in *ExternalSimple, out *InternalSimple, scope conversion.Scope) error {
-			if e, a := "externalVersion", scope.Meta()["srcVersion"].(string); e != a {
+			if e, a := "externalVersion", scope.Meta().SrcVersion; e != a {
 				t.Errorf("Expected '%v', got '%v'", e, a)
 			}
-			if e, a := "", scope.Meta()["destVersion"].(string); e != a {
+			if e, a := "", scope.Meta().DestVersion; e != a {
 				t.Errorf("Expected '%v', got '%v'", e, a)
 			}
 			scope.Convert(&in.JSONBase, &out.JSONBase, 0)