fix(source-control): post-merge remediation also disarms armed lane pull requests #9518

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   needs-triageNot yet classified. Floor until a type and one priority tier are set.Not yet classified. Floor until a type and one priority tier are set.

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2. github-actions commented on Oct 23, 2026

   

   github-actionsBot

   on Oct 23, 2026 – with GitHub Actions

   Last edited by melodic-automation-lanes

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   Proposed work class: work-class: scoped
   Basis: automated intake triage; the lanes App applied this class.

   Size: Small
   Complexity: Medium
   Uncertainty: Known
   Flags: none

   Understood: babysit_postmerge.py --remediate dequeues the lane's merge-queue entries after a demotion. It leaves armed, not-yet-queued lanes App pull requests armed, so native auto-merge could enqueue one before the next enable-auto-merge reader run disarms it. The fix is to disarm every armed lanes App pull request in the same run that dequeues. It needs a test, and a pull request armed by a person (not the lanes App) must be left alone. The issue states the problem and the done-when clearly, so nothing is missing. I found no likely duplicates among the open issues. #9508 is the related work you mentioned.

   _{Automated triage, applied by the lanes App.}
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   priority: mediumReal value, no hard deadline; normal backlog flow.Real value, no hard deadline; normal backlog flow.

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   status: readyTriaged, unblocked, and fully specified; eligible to pick up.Triaged, unblocked, and fully specified; eligible to pick up.

   work-class: scopedA briefed fix or small feature; blast radius bounded by the brief, tests exist.A briefed fix or small feature; blast radius bounded by the brief, tests exist.

   status: needs-decisionAwaiting a human or maintainer judgment call.Awaiting a human or maintainer judgment call.

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7. melodic-automation-lanes commented on Oct 23, 2026

   

   melodic-automation-lanesBot

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   Not admitted to the issue lane: it has no - [ ] task list to check. A recorded decision does not change these rules (.github/actions/resolve-config/admission-rules.json); a person who wants it worked adds agent-ready.
8. melodic-automation-lanes commented on Oct 23, 2026

   

   melodic-automation-lanesBot

   on Oct 23, 2026

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   Refinement. A read-only run explored this repository, searched its issues and pull requests, and read the allowed docs to draft what follows. It is model text, to check, not instructions.

   Intended outcome: When remediate() in babysit_postmerge.py dequeues the lane's merge-queue entries after a demotion, it also disarms every open lanes App pull request with auto-merge armed, and leaves person-armed pull requests alone.

   Related work

   • fix(source-control): judge a native auto-merge of a lane pull request in post-merge #9459 (related): Merged work on judging native auto-merge of lane pull requests in post-merge, same file and area; check for overlap.
   • feat(source-control): add the babysit post-merge check and remediation #7327 (related): Added the babysit post-merge check and the remediation this issue extends.
   • feat(source-control): demote pr-merge only for post-merge failures the merges could have caused #8968 (related): Changed which post-merge failures demote pr-merge, and so which failures trigger remediation.

   Open questions

   1. Which pull requests must remediation disarm: those authored by the lanes App, or those whose newest auto-merge enable event was made by the lanes App?
      RECOMMENDED: Disarm an open pull request only when the lanes App authored it and the lanes App made the newest AutoMergeEnabledEvent, the same test native_auto_merge uses; a person-armed pull request, or one with a person's newest arm, is left alone. Basis: plugins/source-control/skills/babysit-prs/scripts/babysit_postmerge.py:527-543
   2. How should remediation find the armed pull requests, given that nothing in babysit_postmerge.py lists them today?
      RECOMMENDED: Add a read of open pull requests with autoMergeRequest not null (author, id, number, newest auto-merge event actor), paginated and failing with PostMergeReadError if the read is partial, as _identity_entries does for the queue. Disarm with the disablePullRequestAutoMerge mutation already defined as DISARM_MUTATION in babysit_merge.py:2924. Basis: plugins/source-control/skills/babysit-prs/scripts/babysit_postmerge.py:2202-2225 and babysit_merge.py:2924
   3. Should a failed disarm stop the rest of remediation?
      RECOMMENDED: No. Try every pull request, collect failures into report errors as a disarm entry, and carry on to the demotion issue, as dequeue_identity_entries does. Add a disarmed list to the report next to dequeued. Basis: plugins/source-control/skills/babysit-prs/scripts/babysit_postmerge.py:2236-2268 and 2703-2704
   4. Should the disarm run only when verdict.failures is non-empty, like the dequeue?
      RECOMMENDED: Yes, in the same block as the dequeue, so a verdict with no failure still writes nothing. Basis: plugins/source-control/skills/babysit-prs/scripts/babysit_postmerge.py:2689-2704
   5. Does the native-path demotion hold from #​9508 already cover part of this, and is that issue a dependency?
      RECOMMENDED: Check whether #​9508 has merged before starting; the issue says the gap was found while building it. I could not open it, so this is unconfirmed. Basis: judgment

   Sources read

   • plugins/source-control/skills/babysit-prs/scripts/babysit_postmerge.py:2236-2268: dequeue_identity_entries dequeues only the identity's queue entries and never touches armed pull requests
   • plugins/source-control/skills/babysit-prs/scripts/babysit_postmerge.py:2689-2704: remediate dequeues once, only when the verdict has failures, and records errors in the report
   • plugins/source-control/skills/babysit-prs/scripts/babysit_postmerge.py:510-549: native_auto_merge treats an arm as the lanes' own when the identity authored the pull request and made the newest enable event
   • plugins/source-control/skills/babysit-prs/scripts/babysit_merge.py:2924-2927: DISARM_MUTATION calls disablePullRequestAutoMerge
   • plugins/source-control/skills/babysit-prs/scripts/tests/test_babysit_postmerge.py:2316-2361: existing remediate tests that dequeue and never touch another actor's entry; the new tests can follow them
   • /.github/scripts/pr-merge/enable-auto-merge.mjs:243-246: the arm script acts only on pull requests authored by the lanes App bot

   _{Automated refinement by the lanes App. Answer with a comment whose first line is **Decision recorded.**.}
9. kyle-sexton

   closed this as completedin #9538on Oct 24, 2026