tree 3649d9d41dc1598f0a76f48f386cd27bcdae6728
parent e52379a5c2296343cc0c859d98f13477063775e1
author Joe Tsai <joetsai@digital-static.net> 1552719934 -0700
committer Joe Tsai <thebrokentoaster@gmail.com> 1552935016 +0000

cmd/protoc-gen-go: rely on protoimpl for basic helpers

The EnumName, UnmarshalJSONEnum, and CompressGZIP helpers currently live
in v1 protoapi, which would cause all generated messages to depend on v1.
In an effort to break the dependency of v2 on v1, we move these helper
functions to v2 (and re-written to take advantage of protobuf reflection).

These helpers are unfortunate, but we cannot eliminate the functionality
that they implement since they are exposed in the publicly generated API.

Since EnumName does not rely on the enum maps, it removes another dependency
on those variables. Eventually, we can get to the point where these variables
(though declared) are not linked into the binary if the user does not use them.

Also, we rely on the v1 proto package for registration instead of v1 protoapi.
This may re-introduce a cyclic dependency on descriptor proto again in the
future, but the better approach is to just start registering with v2.

Change-Id: Id755585a7a1df14e4a6a2dfa650df221a3c153fb
Reviewed-on: https://go-review.googlesource.com/c/protobuf/+/167921
Reviewed-by: Damien Neil <dneil@google.com>