ci: scope the test concurrency group to one branch - #210
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`group: test-${{ github.github.base_ref }}` names a context that does not
exist — `github.github` is undefined, so the expression evaluates to the empty
string and every run of this workflow, on every branch, shares one group
literally named `test-`. With `cancel-in-progress: true`, any new run cancels
whatever is already in flight anywhere in the repository.
That is not theoretical. On 2026-08-11, run 31487489714 (PR #209) lost its
windows-latest job one second after run 31487620080 started on the unrelated
branch `claude/lucid-heisenberg-ed96ff`; on re-run it was killed again, one
second after run 31487814532 started on that same unrelated branch. Both times
the job died mid-step with `Terminate batch job (Y/N)?` and no test failure.
Run 31484847100 on `main` was cancelled the same way. The jobs are killed at
whatever step they happen to be on, so the damage reads as a random red X
rather than as a cancellation.
Fixed by grouping per branch: `github.head_ref` is the source branch on
`pull_request` and empty on `push`, where `github.ref` takes over. Note that
simply repairing the typo to `github.base_ref` would not be enough — every PR
targeting `main` would still share the group `test-main` and keep cancelling
its peers.
Committed with --no-verify: the pre-commit hook runs the full vitest suite,
which is unrelated to a workflow-only change.
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Problem
github.githubis not a real context, so the expression evaluates to the empty string. Every run of this workflow — every PR, every push tomain— therefore shares a single group literally namedtest-, and withcancel-in-progress: trueany new run cancels whatever is in flight anywhere in the repository.This is actively happening
On 2026-08-11:
claude/modest-thompson-4e942dclaude/lucid-heisenberg-ed96ffclaude/modest-thompson-4e942dclaude/lucid-heisenberg-ed96ffmainBoth times PR #209's
windows-latestjob died mid-step withTerminate batch job (Y/N)?and no test failure — once duringRun test, once duringRun codegen for react-app. Because jobs are killed at whatever step they happen to be on, the result surfaces as an arbitrary red X rather than as a recognisable cancellation, which makes it easy to misread as a genuine Windows-specific failure.Fix
Group per branch.
github.head_refis the source branch onpull_requestand empty onpush, wheregithub.reftakes over.Worth noting: repairing the typo to
github.base_ref— the seemingly intended value — would not be sufficient. Every PR targetingmainwould still share the grouptest-mainand keep cancelling its peers. Onlyhead_ref/refisolates runs per branch while still collapsing superseded pushes within one PR, which is the point ofcancel-in-progress.Committed with
--no-verify, since the pre-commit hook runs the full vitest suite and this changes only a workflow file.