tree 48e9329c2351b5716e4dc96c3a7dafb80d9df005
parent 1c7462c1baab35e8c0ee50f4db30ee266902a21b
author Joe Tsai <joetsai@digital-static.net> 1553550092 -0700
committer Joe Tsai <thebrokentoaster@gmail.com> 1553619811 +0000

cmd/protoc-gen-go: generate for v2-only dependencies

This removes yet another set of dependencies of v2 on v1.
The only remaining dependency are in the _test.go files,
primarily for proto.Equal.

Changes made:
* cmd/protoc-gen-go no longer generates any functionality that depends
on the v1 package, and instead only depends on v2.
* internal/fileinit.FileBuilder.MessageOutputTypes is switched from
protoreflect.MessageType to protoimpl.MessageType since the
implementation must be fully inialized before registration occurs.
* The test for internal/legacy/file_test.go is switched to a legacy_test
package to avoid a cyclic dependency.
This requires Load{Enum,Message,File}Desc to be exported.

Change-Id: I43e2fe64cff4eea204258ce11e791aca5eb6e569
Reviewed-on: https://go-review.googlesource.com/c/protobuf/+/169298
Reviewed-by: Damien Neil <dneil@google.com>