CI-9: a stacked PR is skipped, and a skipped check clears the merge gate #95
Merged
admin
merged 3 commits from 2026-09-19 14:55:13 +02:00
CI-9 into release/1.0
3
Commits
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  adminandClaude Opus 5
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ca8fd01819 |
CI-9: correct the guard comment's grading claim, and name the third blind spot
checks / unit (pull_request) Successful in 7m54s
Documentation only - no change to the guard, the trigger, or any step. The guard's comment block contradicted itself. It said the pull request that reintroduces a filter "is still graded by the unfiltered workflow which is on the base today", while the checkout step's note a few lines below says grading uses the HEAD's workflow. The head's is correct, and the review measured it on PR #101: head carrying a filter that excludes the base, base carrying the unfiltered workflow -> no run, context posted `skipped`, rollup `success`, gate cleared (409). The wrong version made the step sound like an unconditional ratchet. What is actually true is narrower: it bites whenever the reintroduced filter still names the pull request's own base, which is the ordinary case. That correction exposes a third blind spot, worse than the two already listed. A reintroduced `branches:` filter that simply does not name the base escapes the guard entirely, because the pull request carrying it is itself skipped. It needs no craft - `branches: [main]` from a template, or a tidy-up to `[master]`, which nothing in this repository's history has ever targeted - and it lands as a skipped, laundered, untested merge into release/1.0. After that every subsequent pull request is skipped as well: the gate off completely, not merely the stacked case leaking. It is documented, not fixed, and deliberately so. No in-repo guard can close it, because any such guard lives inside the workflow that gets skipped. Closing it needs a second permanently unfiltered workflow whose context is added to release/1.0's `status_check_contexts` - a forge change, the owner's decision, being put to them separately, and explicitly not a blocker on CI-9. Co-Authored-By: Claude Opus 5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01BwRLw7eKYj2byVdwB6kbjU |
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adminandClaude Opus 5
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d2ad080e45 |
CI-9: guard the trigger mechanically, and re-derive two figures I made up
checks / unit (pull_request) Successful in 7m55s
Review findings on PR #95.
1. Two figures in the header were written under the word "measured" and were
not measured. "of the 50 pull requests in this repository's history, 49..."
came from a /pulls call I did not notice was truncated at Gitea's 50-item
page cap; and "#93 was stacked on TEL-10 five days ago" was invented - #93
was created 2026-09-19T10:05:00 and merged 11:05:26, the same morning, under
three hours before CI-9 was opened. Both re-derived from a paged API query
and now stated with their denominator: 93 pull requests predate this ticket
(#1..#93, excluding CI-9's own #94..#98), 92 against release/1.0, exactly one
stacked (#2, TEL-01 -> SAFETY-04). The 92 is flagged as an upper bound rather
than a census, because the API reports a pull request's CURRENT base and so
hides any that was opened stacked and later retargeted - which is #93 itself.
The ratio, and so the cost argument, is unchanged.
2. The fix rested on an invariant - checks.yml has no event filter - that was
defended only by a comment. Prose has already failed in this exact file:
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adminandClaude Opus 5
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074157c4c2 |
CI-9: drop the pull_request branches filter, because a skipped check clears the gate
checks / unit (pull_request) Successful in 7m57s
`branches: [release/1.0, master]` meant a stacked pull request - one based on another feature branch - never matched. Gitea does not stay silent about a workflow it sits out: it posts the required context itself with state `skipped`, the combined-status rollup reports that as `success`, and the merge gate accepts it. Retargeting does not repair it, because the skip is a commit status on the head sha and so survives the base change. Measured on Gitea 1.27.3 with throwaway PR #94 against a branch carrying a copy of release/1.0's protection rule: only status is `skipped` -> POST .../merge 409 head out of date (CLEARED) no status at all -> POST .../merge 405 not all required (refused) status `pending` -> POST .../merge 405 not all required (refused) status `success` -> POST .../merge 409 head out of date (CLEARED) The 409s come from a deliberately wrong head_commit_id in the probe, which Gitea checks only after branch protection - so a 409 means the request had already cleared the gate, and nothing was ever merged. `skipped` is the only state that leaks. Fixing this at the gate is not possible. Gitea branch protection can require that a context is PRESENT, never that it is SUCCESS: its whole status-check vocabulary is `enable_status_check` and `status_check_contexts`, per this server's own /swagger.v1.json. So the fix has to be upstream - never emit a skip - which means no event filter. Cost: every pull request now runs the full ~8 minute suite, including the intermediate steps of a stack. 49 of the 50 pull requests in this repository's history were opened straight against release/1.0 and would have run anyway. Also corrects two things CI-01's header stated as fact. A filter miss is fail-OPEN, not the fail-closed pending-forever it described; and it is a skip-ci keyword, not a filter miss, that actually withholds the context and leaves it pending. Co-Authored-By: Claude Opus 5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01BwRLw7eKYj2byVdwB6kbjU |