Consider moving to google.golang.org/protobuf/proto

[mem]

github.com/golang/protobuf/proto has been "deprecated" in favor of google.golang.org/protobuf/proto. For this codebase in particular this involves changing calls to proto.MarshalTextString to prototext.Marshal.

This is related to #281.

[beorn7]

My assumption so far is that the move would mean a breaking change for the users of prometheus/client_golang (which exposes a few protobuf specific parts in its interface). If we can pull it off without a breaking change, great. But if it does mean a breaking change, it has to be navigated carefully and in coordination with @kakkoyun and @bwplotka .

[bwplotka]

Ack, I think we have to do it at some point. Added ticket on our side: prometheus/client_golang#1175

[zhsj]

Continue my comments #427 (comment) here, since I find it's not easy to get rid of proto.MarshalTextString.

proto.MarshalTextString results a string with <,> as delim, but prototext.Marshal uses {,} as delim. The upstream doc says the text format is not stable. Should we rely on this?

Besides, there's no decoder for FmtProtoText, is there any user for this format?

[beorn7]

I don't think anyone depends on the exact format of FmtProtoText (at least I don't think anyone should depend on it).

[SuperQ]

I fixed the issue of proto.MarshalTextString() by updating prometheus/client_model to google.golang.org/protobuf/proto first.

This is now fixed with #479