Two changes to make the `flake-go` workflow produce better signal when
something hangs or flakes at low rates.
**Job timeout (20m → 25m).** The Go-level `-timeout 20m` baked into
`make test` (`Makefile:1428`) currently raced the runner's 20m
hard-kill, so a hanging test got SIGTERM'd by Actions instead of
SIGQUIT'd by Go, and we never got the goroutine dump. Bumping the
workflow job to 25m mirrors the layering already used by `test-go-pg` in
`ci.yaml:409` and gives Go's timeout the 5m head start it expects.
**Test count (25 → 35).** Catches lower-frequency flakes that 25
attempts miss too often. For a 5% per-run flake, detection probability
goes from ~72% at n=25 to ~83% at n=35; for 1–2% flakes the lift is
larger. The longest successful flake-go run to date was 11m49s at n=25,
so n=35 should peak around ~16–17m and stay well inside the new 25m
budget.
The Flake Check workflow runs `make test` through the `test-go-pg`
action, which invokes `gotestsum`, but the workflow never installs it.
The mise refactor (#25727) deleted the `setup-go` action that previously
installed `gotestsum` implicitly, and added explicit `mise install ...
go:gotest.tools/gotestsum` steps to every other Go test job. The flake
check's `Install Go mise tools` step only listed `whichtests`, so the
check fails with `gotestsum: command not found` whenever it selects
changed tests to run.
Add `go:gotest.tools/gotestsum` to the flake check's install step,
matching the other `test-go-pg` jobs in `ci.yaml` and
`nightly-gauntlet.yaml`.
Refs #25727🤖 Generated with [Claude Code](https://claude.com/claude-code)
Co-authored-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Adds a `flake-go` workflow that hunts for ordering-dependent and racy Go
tests on pull requests. The workflow runs only on PRs (cancelling
earlier runs on new commits) and skips test execution when no Go test
files changed.
A single `flake_go` job uses
[coder/whichtests](https://github.com/coder/whichtests) with
`--coalesce` to compute the directly-modified `Test*` functions from the
PR diff and emit them as one target row. The same job then runs those
selected tests on a deliberately resource-constrained 4-vCPU runner with
4x parallelism oversubscription, `-count=25`, and `-shuffle=on` to
amplify contention and surface flakes.
Pinned at
[coder/whichtests@ec33bab](https://github.com/coder/whichtests/commit/ec33bab1ec04cd86beb7a61a069db4463dba63f5).
Reuses the `test-go-pg` composite (with its new `run-regex`,
`test-shuffle`, and `gotestsum-json-file` inputs) and the
`go-test-failure-report` composite, both introduced on the base branch
(#25670), so this workflow shares one implementation of the gotestsum +
failure-report path with the existing CI jobs.
`Makefile` adds `TEST_SHUFFLE` support and single-quotes `RUN` so
whichtests' regex survives shell parsing.
Stacked on top of #25670.
Demo @
https://github.com/coder/coder/actions/runs/26494322649/job/78018779381?pr=25667
Closes CODAGT-381
Ethan