Buildkite: Try same-named branches when cloning core repos, for PRs originating from official dlang repos

[kinke]

No description provided.

[kinke]

I hope this is the source repo of the PR. I.e., kinke/druntime when opening a druntime PR from my fork. https://buildkite.com/docs/pipelines/environment-variables#bk-env-vars-buildkite-pull-request-repo isn't too clear.

[kinke]

Looks alright from what I can tell - this is a PR from an official dlang repo itself, BUILDKITE_PULL_REQUEST_REPO='git://github.com/dlang/ci.git', and CI checks out the same-named DMD and druntime branches (dlang/dmd#13593 and dlang/druntime#3718). LDC failing is to be expected, as this breaking change affects the frontend itself.

[RazvanN7]

Is the buidkite ldc failure going away after dlang/dmd#13593 is merged?

[kinke]

Not really - it depends on whether Buildkite does a full or shallow git clone of dmd AFAICT. If it's a shallow clone without .git subdir, the compiler defines __VERSION__ as 2099 with that DMD PR, and enables the opEquals fix. That fix breaks older (read: all current) frontends, so LDC needs to be prepared (ldc-developers/ldc#3910) and then the Buildkite ref bumped to master. I was thinking of doing that in a separate PR here (this PR should be green after merging, won't test the fix22717 branches anymore).