This is a cascading problem. grpc-go is now broken since this package is a dependency of ours and we support Go 1.6. We are blocked on deprecating 1.6 and updating our imports until generated proto files use the standard context package. AppEngine only supports Go1.6, so I believe the proto compiler can't be changed until that is updated.
Is it possible to revert these context changes and hold off on them until Go1.6 is less widely used?
It's been 14 months since Go 1.6. App Engine can't get another release out? Is that really what this is all about?
Go's policy is that we only test and maintain the past two releases. I could add some build tag chicanery into x/net/trace, but our builders aren't testing 1.6 anymore. I don't want to revert the change. We want to make forward progress on cleanups and other people want us to use std context.