x/build: trybots should test subrepos against previous Go releases

[bradfitz]

Subrepos trybots should test against Go tip, Go 1.N, Go 1.N-1.

[dsnet]

What's the general policy for how many versions back we maintain support on a given subrepo?

[bradfitz]

In general, the two most recent. (which means between 12-18 months for us)

[siennathesane]

I'm new to the language contribution process, but I'd like to help with this issue since it seems like something simple (relative). How can I help with this issue?

[bradfitz]

This is a hard one to contribute to because the Go build system is large and has many moving parts, and it's difficult to run without access to our GCP project, and/or paying for it.

The code is in https://github.com/golang/build (mostly in cmd/coordinator) and you can run it in localhost machine. Kinda. But it might require some hackery for local testing. That code bitrots often and needs occasional love. I suspect it's partially broken.

[siennathesane]

Alright, I'll see if I can make some progress, and update here if I need help. Do I need a builder hash at all?

[bradfitz]

Nope.

[siennathesane]

I'm getting this issue when trying to run it locally:

failed to get a token source: google: could not find default credentials. See https://developers.google.com/accounts/docs/application-default-credentials for more information.

Do those creds need to be on the Go build system or will any credentials work?

[bradfitz]

You're starting to discover why this is difficult. You shouldn't need any credentials in localhost mode. But we also don't develop the build system in localhost mode, so you probably need to fix it up to work.

[siennathesane]

Fix the system to fix the system, can do! I'll create a sub-issue to allow it to work in localhost mode and tackle that first.