[ci-scan-feedback] Guard fixer against retired-leg / already-fixed help-wanted PRs #131699

Triggering signals

• ([ci-scan-feedback] Guard fixer against retired-leg / already-fixed help-wanted PRs #131644, prior-tick feedback captured as an issue that never became a prompt edit: "Guard fixer against retired-leg / already-fixed help-wanted PRs", [ci-scan-feedback] Guard fixer against retired-leg / already-fixed help-wanted PRs #131644) — the guard was described but never landed in ci-failure-fix.md.
• ([ci-fix] Needs review: Marshal mono_ios_* string args as UTF-8 for NativeAOT ILC (refs #130219) #130232, maintainer kotlarmilos: root cause "already fixed" + wrong cause, [ci-fix] Needs review: Marshal mono_ios_* string args as UTF-8 for NativeAOT ILC (refs #130219) #130232) — help-wanted PR against an already-corrected HEAD.
• ([ci-fix] Needs review: root CustomAttributeDecoderTests enum types for Apple-mobile trimming (refs #128450) #130106, maintainer MichalStrehovsky: "unlikely to help... already rooted", [ci-fix] Needs review: root CustomAttributeDecoderTests enum types for Apple-mobile trimming (refs #128450) #130106) — help-wanted PR whose change was a no-op at HEAD.
• Rubric finding: fix_reject_rate_30d = 50.0% (3/6), 🔴; 100% of [ci-fix] PRs this window are kind: help, and the dominant rejection class is "leg no longer exercised in CI" or "already fixed at HEAD".

Proposed edits

• (.github/workflows/ci-failure-fix.md Step 5.2, after the Platform crypto-config caution ~L211: added a Retired-leg / already-fixed caution) — require confirming the failing leg is still exercised and the root cause is not already at HEAD before staging a candidate; route retired legs to -> skipped: failing leg no longer exercised in CI and already-fixed cases to the existing -> skipped: candidate fix already present in source, tied to the [ci-fix] Needs review: Marshal mono_ios_* string args as UTF-8 for NativeAOT ILC (refs #130219) #130232 / [ci-fix] Needs review: root CustomAttributeDecoderTests enum types for Apple-mobile trimming (refs #128450) #130106 rejection class.

Expected behavior change

The next fixer run will diff the implicated file(s) at HEAD against the failing build and check that the leg still appears in current pipeline definitions before opening a confident or help-wanted PR. This suppresses the dominant 30d rejection class — help-wanted PRs "fixing" retired legs (Mono mobile / EOL-OS) or root causes already merged at HEAD — which drove the 50% fixer rejection rate this window.

network:
  allowed:
    - defaults
    - "awmgmcpg"

Generated by CI Outer-Loop Failure Scanner — Feedback · 627.2 AIC · ⌖ 14.9 AIC · ⊞ 17.1K · ◷

To create a pull request with the changes:

# Download the artifact from the workflow run
gh run download 30701485019 -n agent -D /tmp/agent-30701485019

# Fetch the bundle into a temporary ref, then update the local branch
git fetch /tmp/agent-30701485019/aw-ci-scan-feedback-retired-leg-guard.bundle refs/heads/ci-scan-feedback-retired-leg-guard:refs/bundles/create-pr-ci-scan-feedback-retired-leg-guard-62763771fe7fdc1d-7bc00738
git update-ref refs/heads/ci-scan-feedback-retired-leg-guard-62763771fe7fdc1d refs/bundles/create-pr-ci-scan-feedback-retired-leg-guard-62763771fe7fdc1d-7bc00738
git checkout ci-scan-feedback-retired-leg-guard-62763771fe7fdc1d
# Ensure the working tree matches the updated branch
git reset --hard
# Remove the temporary bundle ref
git update-ref -d refs/bundles/create-pr-ci-scan-feedback-retired-leg-guard-62763771fe7fdc1d-7bc00738

# Push the branch to origin
git push origin ci-scan-feedback-retired-leg-guard-62763771fe7fdc1d

# Create the pull request
gh pr create --title '[ci-scan-feedback] Guard fixer against retired-leg / already-fixed help-wanted PRs' --base main --head ci-scan-feedback-retired-leg-guard-62763771fe7fdc1d --repo dotnet/runtime