Migrate pull request automation away from pull_request_target

.github/workflows/check-change-note.yml

@@ -1,10 +1,11 @@
 name: Check change note
 
 permissions:
+  contents: read
   pull-requests: read
 
 on:
-  pull_request_target:
+  pull_request:
     types: [labeled, unlabeled, opened, synchronize, reopened, ready_for_review]
     paths:
       - "*/ql/src/**/*.ql"
@@ -23,7 +24,7 @@ jobs:
     env:
       REPO: ${{ github.repository }}
       PULL_REQUEST_NUMBER: ${{ github.event.number }}
-      GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+      GH_TOKEN: ${{ github.token }}
     runs-on: ubuntu-latest
     steps:
 

.github/workflows/labeler-apply.yml

@@ -0,0 +1,100 @@
+name: "Pull Request Labeler Apply"
+
+on:
+  workflow_run:
+    workflows: ["Pull Request Labeler"]
+    types: [completed]
+
+permissions: {}
+
+jobs:
+  triage:
+    if: >
+      github.event.workflow_run.event == 'pull_request' &&
+      github.event.workflow_run.conclusion == 'success'
+    runs-on: ubuntu-latest
+    permissions:
+      actions: read
+      contents: read
+      pull-requests: write
+    steps:
+      - name: Validate pull request from workflow_run
+        id: validate
+        env:
+          GH_TOKEN: ${{ github.token }}
+          REPO: ${{ github.repository }}
+          RUN_ID: ${{ github.event.workflow_run.id }}
+        run: |
+          set -euo pipefail
+
+          run_json=$(gh api "repos/$REPO/actions/runs/$RUN_ID")
+          event=$(jq -r '.event' <<<"$run_json")
+          conclusion=$(jq -r '.conclusion' <<<"$run_json")
+          head_sha=$(jq -r '.head_sha' <<<"$run_json")
+          head_repo=$(jq -r '.head_repository.full_name // empty' <<<"$run_json")
+
+          if [ "$event" != "pull_request" ] || [ "$conclusion" != "success" ]; then
+            echo "apply=false" >> "$GITHUB_OUTPUT"
+            exit 0
+          fi
+
+          pr_number=$(jq -r 'if (.pull_requests | length) == 1 then .pull_requests[0].number else empty end' <<<"$run_json")
+
+          if [ -z "$pr_number" ]; then
+            prs_json=$(gh api -H 'Accept: application/vnd.github+json' "repos/$REPO/commits/$head_sha/pulls" || echo '[]')
+            pr_number=$(jq -r 'map(select(.state == "open")) | if length == 1 then .[0].number else empty end' <<<"$prs_json" 2>/dev/null || true)
+          fi
+
+          if [ -z "$pr_number" ]; then
+            head_owner=$(jq -r '.head_repository.owner.login // empty' <<<"$run_json")
+            head_branch=$(jq -r '.head_branch // empty' <<<"$run_json")
+            if [ -n "$head_owner" ] && [ -n "$head_branch" ]; then
+              prs_json=$(gh api --method GET "repos/$REPO/pulls" -f state=open -f head="$head_owner:$head_branch" || echo '[]')
+              pr_number=$(jq -r 'if length == 1 then .[0].number else empty end' <<<"$prs_json" 2>/dev/null || true)
+            fi
+          fi
+
+          if [ -z "$pr_number" ]; then
+            echo "Could not identify a unique open pull request for workflow run $RUN_ID; skipping."
+            echo "apply=false" >> "$GITHUB_OUTPUT"
+            exit 0
+          fi
+
+          pr_json=$(gh api "repos/$REPO/pulls/$pr_number" || true)
+          if [ -z "$pr_json" ]; then
+            echo "Pull request #$pr_number could not be fetched; skipping."
+            echo "apply=false" >> "$GITHUB_OUTPUT"
+            exit 0
+          fi
+
+          state=$(jq -r '.state // empty' <<<"$pr_json" 2>/dev/null || true)
+          base_repo=$(jq -r '.base.repo.full_name // empty' <<<"$pr_json" 2>/dev/null || true)
+          pr_head_sha=$(jq -r '.head.sha // empty' <<<"$pr_json" 2>/dev/null || true)
+          pr_head_repo=$(jq -r '.head.repo.full_name // empty' <<<"$pr_json" 2>/dev/null || true)
+
+          if [ -z "$state" ]; then
+            echo "Pull request #$pr_number could not be parsed; skipping."
+            echo "apply=false" >> "$GITHUB_OUTPUT"
+            exit 0
+          fi
+
+          if [ "$state" != "open" ] || [ "$base_repo" != "$REPO" ]; then
+            echo "Pull request #$pr_number is no longer an open pull request against $REPO; skipping."
+            echo "apply=false" >> "$GITHUB_OUTPUT"
+            exit 0
+          fi
+
+          if [ "$pr_head_sha" != "$head_sha" ] || [ "$pr_head_repo" != "$head_repo" ]; then
+            echo "Pull request #$pr_number changed since workflow run $RUN_ID; skipping stale labeling."
+            echo "apply=false" >> "$GITHUB_OUTPUT"
+            exit 0
+          fi
+
+          echo "number=$pr_number" >> "$GITHUB_OUTPUT"
+          echo "apply=true" >> "$GITHUB_OUTPUT"
+
+      - uses: actions/labeler@v4
+        if: steps.validate.outputs.apply == 'true'
+        with:
+          repo-token: "${{ github.token }}"
+          pr-number: ${{ steps.validate.outputs.number }}

.github/workflows/labeler.yml

@@ -1,15 +1,16 @@
 name: "Pull Request Labeler"
+
 on:
-- pull_request_target
+  pull_request:
+    types: [opened, synchronize, reopened]
 
 permissions:
   contents: read
-  pull-requests: write
+  pull-requests: read
 
 jobs:
-  triage:
+  request-labels:
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/labeler@v4
-      with:
-        repo-token: "${{ secrets.GITHUB_TOKEN }}"
+      - name: Request privileged labeling
+        run: echo "Labels are applied by the workflow_run writer after re-validating the pull request."