docs(ci): a killed job loses its if: always() steps — gotchas §9 (refs #161)

Records what #161's job metadata actually shows (steps 15-18 as 0-second
failures stamped at the kill), how to read step timings via the API instead of
trusting a truncated log, and the two conventions that follow: bound the work
inside the tool so it can still report, and never let an auto-waiting
Playwright action serve as the timeout.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

docs/runbooks/gitea-actions-gotchas.md

@@ -245,3 +245,47 @@ the verify-stack check table, and per-spec e2e results (`infra/playwright-summar
 - Getting a report out of the e2e container: Playwright writes `playwright-report.json`
   inside the container; `infra/run-e2e-check.sh` `docker cp`s it back to the host
   (capturing the test exit code first) so the summary step can read it.
+
+---
+
+## 9. `if: always()` does not survive the job being killed — bound the work itself
+
+`if: always()` makes a step run when an *earlier step failed*. It does **not** help when
+the job as a whole is stopped: the run's remaining steps are simply never dispatched.
+
+That is how #161 lost its diagnosis. `verify-stack` entered `make verify-e2e` at 09:48:17
+and the job ended at 10:14:54 — 26½ minutes later, mid-suite. Every step after the e2e
+shows a **0-second `failure`** stamped at that same instant:
+
+```
+14 failure  09:48:17 -> 10:14:54  Self-service e2e (Playwright, login → submit → success)
+15 failure  10:14:54 -> 10:14:54  verify-stack check summary       ← if: always()
+16 failure  10:14:54 -> 10:14:54  e2e spec summary                 ← if: always()
+17 failure  10:14:54 -> 10:14:54  Dump container logs on failure   ← if: failure()
+18 failure  10:14:54 -> 10:14:54  Tear down                        ← if: always()
+```
+
+So the per-spec summary, the container-log dump and the teardown never ran, and the job
+log — which also loses whatever the killed process had buffered — ended at a single `✘`
+line. A job that dies takes its own post-mortem with it.
+
+**Read the step timings, not just the log.** `GET /api/v1/repos/{owner}/{repo}/actions/jobs/{id}`
+returns every step with `started_at`/`completed_at`; a row of identical zero-length
+steps at the end means *killed*, not *silent*. (Job ids come from
+`…/actions/runs/{run}/jobs`, and that route returns only the **latest attempt** — a
+re-run hides the failed one, so keep the failing job id from the original report. Logs:
+`…/actions/jobs/{id}/logs`, see also `gitea-ci-logs`.)
+
+**Conventions that follow:**
+
+- **Bound long-running work inside the tool**, where it can still report. Playwright's
+  `globalTimeout` (`tests/e2e/playwright.config.ts`) ends the run, writes the JSON
+  report and exits, so the summary and log-dump steps still get their turn. A
+  `timeout-minutes` on the job would reproduce the very failure above.
+- **Never let an auto-waiting action be the timeout.** Playwright actions (`fill`,
+  `click`) inherit the *test* timeout, not `expect.timeout`, so a missing element costs
+  the full 90 s and reports `locator.fill: Test timeout …` — the symptom. Assert the
+  element visible first with its own budget and a message (`tests/e2e/keycloak-login.ts`).
+- Remember `concurrency.cancel-in-progress: true` in `ci.yaml`: a new push to the same
+  ref, or a re-run, kills the in-flight run the same way. Check `run_attempt` before
+  concluding a job hung.