internal/impl: return nil for nil enum or message
Ensure that EnumOf, EnumDescriptorOf, EnumTypeOf, ProtoMessageV1Of,
ProtoMessageV2Of, MessageOf, MessageDescriptorOf, and MessageTypeOf
all return nil if passed a nil interface.
This parallels the behavior of reflect.TypeOf or reflect.ValueOf,
which return nil or an invalid value rather than panicking.
Change-Id: I461f15542f16cb0922d627bca6fcad5fc27d87e2
Reviewed-on: https://go-review.googlesource.com/c/protobuf/+/213239
Reviewed-by: Damien Neil <dneil@google.com>
diff --git a/internal/impl/api_export.go b/internal/impl/api_export.go
index d7b844d..54cf956 100644
--- a/internal/impl/api_export.go
+++ b/internal/impl/api_export.go
@@ -24,27 +24,42 @@
type enum = interface{}
// EnumOf returns the protoreflect.Enum interface over e.
+// It returns nil if e is nil.
func (Export) EnumOf(e enum) pref.Enum {
- if ev, ok := e.(pref.Enum); ok {
- return ev
+ switch e := e.(type) {
+ case nil:
+ return nil
+ case pref.Enum:
+ return e
+ default:
+ return legacyWrapEnum(reflect.ValueOf(e))
}
- return legacyWrapEnum(reflect.ValueOf(e))
}
// EnumDescriptorOf returns the protoreflect.EnumDescriptor for e.
+// It returns nil if e is nil.
func (Export) EnumDescriptorOf(e enum) pref.EnumDescriptor {
- if ev, ok := e.(pref.Enum); ok {
- return ev.Descriptor()
+ switch e := e.(type) {
+ case nil:
+ return nil
+ case pref.Enum:
+ return e.Descriptor()
+ default:
+ return LegacyLoadEnumDesc(reflect.TypeOf(e))
}
- return LegacyLoadEnumDesc(reflect.TypeOf(e))
}
// EnumTypeOf returns the protoreflect.EnumType for e.
+// It returns nil if e is nil.
func (Export) EnumTypeOf(e enum) pref.EnumType {
- if ev, ok := e.(pref.Enum); ok {
- return ev.Type()
+ switch e := e.(type) {
+ case nil:
+ return nil
+ case pref.Enum:
+ return e.Type()
+ default:
+ return legacyLoadEnumType(reflect.TypeOf(e))
}
- return legacyLoadEnumType(reflect.TypeOf(e))
}
// EnumStringOf returns the enum value as a string, either as the name if
@@ -69,6 +84,7 @@
func (m legacyMessageWrapper) ProtoMessage() {}
// ProtoMessageV1Of converts either a v1 or v2 message to a v1 message.
+// It returns nil if m is nil.
func (Export) ProtoMessageV1Of(m message) piface.MessageV1 {
switch mv := m.(type) {
case nil:
@@ -100,15 +116,23 @@
}
// ProtoMessageV2Of converts either a v1 or v2 message to a v2 message.
+// It returns nil if m is nil.
func (Export) ProtoMessageV2Of(m message) pref.ProtoMessage {
- if mv := (Export{}).protoMessageV2Of(m); mv != nil || m == nil {
+ if m == nil {
+ return nil
+ }
+ if mv := (Export{}).protoMessageV2Of(m); mv != nil {
return mv
}
return legacyWrapMessage(reflect.ValueOf(m))
}
// MessageOf returns the protoreflect.Message interface over m.
+// It returns nil if m is nil.
func (Export) MessageOf(m message) pref.Message {
+ if m == nil {
+ return nil
+ }
if mv := (Export{}).protoMessageV2Of(m); mv != nil {
return mv.ProtoReflect()
}
@@ -116,7 +140,11 @@
}
// MessageDescriptorOf returns the protoreflect.MessageDescriptor for m.
+// It returns nil if m is nil.
func (Export) MessageDescriptorOf(m message) pref.MessageDescriptor {
+ if m == nil {
+ return nil
+ }
if mv := (Export{}).protoMessageV2Of(m); mv != nil {
return mv.ProtoReflect().Descriptor()
}
@@ -124,7 +152,11 @@
}
// MessageTypeOf returns the protoreflect.MessageType for m.
+// It returns nil if m is nil.
func (Export) MessageTypeOf(m message) pref.MessageType {
+ if m == nil {
+ return nil
+ }
if mv := (Export{}).protoMessageV2Of(m); mv != nil {
return mv.ProtoReflect().Type()
}
@@ -134,8 +166,7 @@
// MessageStringOf returns the message value as a string,
// which is the message serialized in the protobuf text format.
func (Export) MessageStringOf(m pref.ProtoMessage) string {
- v := reflect.ValueOf(m)
- if m == nil || (v.Kind() == reflect.Ptr && v.IsNil()) {
+ if m == nil || !m.ProtoReflect().IsValid() {
return "<nil>"
}
b, _ := prototext.MarshalOptions{
