Annotating build errors is broken

Stream: mathlib4

[Michael Rothgang]

There used to be a workflow that would annote build errors or warnings in the "files changed" tab on github: this was extremely helpful. My WIP PR #12879 did not have these. (It builds now, so is not suitable for testing. I can restore an old non-building state if this would help.)
Was this on purpose?

[Damiano Testa]

Could you link or post a screenshot of what you are referring to? I don't remember this workflow.

[Eric Wieser]

I left a comment about this elsewhere; the cause is the error message format changing and no longer matching gcc

[Eric Wieser]

The thing to search zulip for is "problem matchers"

[Eric Wieser]

Ah, I didn't make a thread, only a comment in the release discussion:

Eric Wieser said:

Relating to mathlib CI, it seems that the problem matcher is no longer annotating the diff with build failures