tree a50981ade919ddfba54ab54262e2cb85482b1f41
parent 7bf88d137769ed6baf7e98292a9f5a03ad2d901d
author Damien Neil <dneil@google.com> 1545165907 -0800
committer Damien Neil <dneil@google.com> 1545176302 +0000

reflect/protoreflect: change Options back to an interface{}

Introduce a protoreflect.OptionsMessage interface type to represent
options messages. The protoreflect package can't deal with concrete
options types, to avoid dependency cycles; OptionsMessage serves both
as documentation and a single point to define the constraints we apply
to options.

Change the constraints on options from ProtoMessage to interface{} to
permit use of option message types which only implement the v1
proto.Message interface.

This still leaves a requirement in the internal/legacy package that
options implement protoreflect.ProtoMessage, since that package now uses
the v2 Unmarshal.

Change-Id: I547518ab2c3b90c3911ef641b05b169d50a4b33a
Reviewed-on: https://go-review.googlesource.com/c/154877
Reviewed-by: Joe Tsai <thebrokentoaster@gmail.com>