How could I solve enum conflict？

[hanke0]

It panics when I compile following proto file.
The message says that panic: foo.proto:11:9: symbol "google.protobuf.UNSPECIFIC" already defined at foo.proto:7:9; protobuf uses C++ scoping rules for enum values, so they exist in the scope enclosing the enum, how could I solve it?

syntax = "proto3";

package google.protobuf;

enum Foo {
	UNSPECIFIC = 0;
}

enum B {
	UNSPECIFIC = 0;
}

package main

import (
	"context"
	"fmt"
	"io"
	"strings"

	"github.com/bufbuild/protocompile"
)

type rd struct {
	*strings.Reader
}

func (rd) Close() error {
	return nil
}

var pb = &rd{
	Reader: strings.NewReader(`
syntax = "proto3";

package google.protobuf;

enum Foo {
	UNSPECIFIC = 0;
}

enum Bar {
	UNSPECIFIC = 0;
}`),
}

func main() {
	comp := protocompile.Compiler{
		Resolver: &protocompile.SourceResolver{
			Accessor: func(path string) (io.ReadCloser, error) {
				return pb, nil
			},
		},
	}
	fs, err := comp.Compile(context.Background(), "foo.proto")
	if err != nil {
		panic(err)
	}
	fmt.Println(fs)
}

[jhump]

@hanke0, you must rename one or both of the enum values so they don't have the same name. Apologies if the error message is unclear. But it's saying that those enum value names are in the same lexical scope -- so the fully-qualified name for both elements is google.protobuf.UNSPECIFIC. The enclosing enum's name is not part of its full name (which is also how C++ enums work).

Also see this part of the spec: https://protobuf.com/docs/language-spec#fully-qualified-names

[hanke0]

Is there be an option that I can ignore this error and build successful?
It functions properly in protoc-go and generates code:

type Foo int32

const (
	Foo_ UNSPECIFIC  Foo = 0
)

type Bar int32

const (
	Bar_UNSPECIFIC  Foo = 0
)

@jhump

[timostamm]

@hanke0, the Protobuf source is invalid, and doesn't compile with protoc or buf. To solve the conflict, you'll have to add a prefix to the name:

enum Foo {
  FOO_UNSPECIFIC = 0;
}

enum B {
  B_UNSPECIFIC = 0;
}

If you ignore this error, the Protobuf source won't compile elsewhere, and the compiled descriptors wouldn't be safe to generate code from. Besides C++, there may be other code generators that rely on this limitation to be enforced. So I don't think we want to provide an option to disable the limitation.

It is possible that the limitation will be lifted in a future edition though, see this comment in descriptor.proto.