[ci-scan-feedback] Read ci-fix head.ref via list/get, not search, to close dedup gap

## Triggering signals - **#131981** — help-wanted `[ci-fix]` PR closed unmerged by `kotlarmilos` (MEMBER) on 2026-08-14 with the comment **"Duplicate https://github.com/dotnet/runtime/pull/131515"**. Both PRs target KBE **#131382** with the same `WindowsShell` fix, and #131515 was already **open** (created 2026-07-29) when #131981 was filed (2026-08-07). Step 3 check-1 (branch-prefix `ci-fix/131382-`) should have caught it. https://github.com/dotnet/runtime/pull/131981#issuecomment-5293776596 - **#132541** (merged 2026-08-20, `jkoritzinsky`) established the `ci-fix/<kbe>-...` branch-naming contract so the branch prefix is the deterministic dedup key — but it did not fix how that key is *read* during enumeration. ## Proposed edits - `.github/workflows/ci-failure-fix.md:164` — Step 3 enumeration: `search_pull_requests` never returns `head.ref`, so the branch-prefix key added by #132541 is invisible to search alone. Instruct the fixer to resolve head branches with `list_pull_requests` (open PRs, `fields` incl. `head`) and `pull_request_read get` (merged/closed candidates) before relying on the prefix, and to never treat a `#`-title match as a substitute for the branch key. - `.github/workflows/ci-failure-fix.md:166` — Step 3 check 1: clarify that an empty branch map means "not yet enumerated", not "no open PR", so the fixer enumerates head branches before concluding no open PR exists. ## Expected behavior change The next fixer run will obtain each candidate `[ci-fix]` PR's `head.ref` via `list_pull_requests`/`pull_request_read get` rather than falling back to the GitHub-search `#`-tokenized title match, which drops the leading `#` and is unreliable. This closes the residual dedup gap that allowed help-wanted PR #131981 to be filed against KBE #131382 while #131515 was already open — the fixer will detect the open `ci-fix/131382-` branch and skip with `open fix PR #<n> already exists` instead of opening a duplicate. > [!NOTE] > AI/Copilot-generated (`ci-scan-feedback`). Prompt-only edit to `.github/workflows/ci-failure-fix.md`. > Generated by [CI Outer-Loop Failure Scanner — Feedback](https://github.com/dotnet/runtime/actions/runs/32485521271) · opus48 · 308.9 AIC · ⌖ 25.7 AIC · ⊞ 20.6K · [◷](https://github.com/search?q=repo%3Adotnet%2Fruntime+%22gh-aw-workflow-id%3A+ci-failure-scan-feedback%22&type=pullrequests) <!-- gh-aw-agentic-workflow: CI Outer-Loop Failure Scanner — Feedback, engine: copilot, model: claude-opus-4.8, id: 32485521271, workflow_id: ci-failure-scan-feedback, run: https://github.com/dotnet/runtime/actions/runs/32485521271 --> <!-- gh-aw-workflow-id: ci-failure-scan-feedback --> <!-- gh-aw-workflow-call-id: dotnet/runtime/ci-failure-scan-feedback --> --- > [!NOTE] > This was originally intended as a pull request, but the git push operation failed. > > **Original error:** The process '/usr/bin/git' failed with exit code 1 > > **Workflow Run:** [View run details and download bundle artifact](https://github.com/dotnet/runtime/actions/runs/32485521271) > > The bundle file is available in the `agent` artifact in the workflow run linked above. To create a pull request with the changes: ```sh # Download the artifact from the workflow run gh run download 32485521271 -n agent -D /tmp/agent-32485521271 # Fetch the bundle into a temporary ref, then update the local branch git fetch /tmp/agent-32485521271/aw-ci-scan-feedback-dedup-branch-field.bundle refs/heads/ci-scan-feedback-dedup-branch-field:refs/bundles/create-pr-ci-scan-feedback-dedup-branch-field-865f327628785ee6-e5a19021 git update-ref refs/heads/ci-scan-feedback-dedup-branch-field-865f327628785ee6 refs/bundles/create-pr-ci-scan-feedback-dedup-branch-field-865f327628785ee6-e5a19021 git checkout ci-scan-feedback-dedup-branch-field-865f327628785ee6 # 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-dedup-branch-field-865f327628785ee6-e5a19021 # Push the branch to origin git push origin ci-scan-feedback-dedup-branch-field-865f327628785ee6 # Create the pull request gh pr create --title '[ci-scan-feedback] Read ci-fix head.ref via list/get, not search, to close dedup gap' --base main --head ci-scan-feedback-dedup-branch-field-865f327628785ee6 --repo dotnet/runtime ```