rework pr comment with workflow_run

Author: Daraan

.github/workflows/ci.yml

@@ -99,6 +99,17 @@ jobs:
           path: ./src/.coverage*
           include-hidden-files: true
           compression-level: 0 # no compression
+      
+      - name: Save PR number for coverage report
+        if: ${{ !startsWith(matrix.python-version, 'pypy') }}
+        run: |
+          mkdir -p ./pr
+          echo ${{ github.event.number }} > ./pr/NR
+      - uses: actions/upload-artifact@v4
+        if: ${{ !startsWith(matrix.python-version, 'pypy') }}
+        with:
+          name: pr
+          path: pr/
 
       - name: Test CPython typing test suite
         # Test suite fails on PyPy even without typing_extensions
@@ -136,63 +147,4 @@ jobs:
               repo: "typing_extensions",
               title: `Daily tests failed on ${new Date().toDateString()}`,
               body: "Runs listed here: https://github.com/python/typing_extensions/actions/workflows/ci.yml",
-            })
-
-  report-coverage:
-    name: Report coverage
-
-    runs-on: ubuntu-latest
-
-    needs: [tests]
-    permissions:
-      contents: read
-      pull-requests: write
-
-    if: ${{ always() }}
-
-    steps:
-      - uses: actions/checkout@v4
-        with:
-          persist-credentials: false
-      - name: Set up Python
-        uses: actions/setup-python@v5
-        with:
-          python-version: "3"
-      - name: Download coverage artifacts
-        uses: actions/download-artifact@v4
-        with:
-          pattern: .coverage_*
-          path: .
-          # merge only when files are named differently
-          merge-multiple: true
-      - name: Install dependencies
-        run: pip install coverage
-      - name: Combine coverage results
-        run: |
-          # List the files to see what we have
-          echo "Combining coverage files..."
-          ls -aR .coverage*
-          coverage combine .coverage*
-          echo "Creating coverage report..."
-          coverage report
-          coverage xml
-
-      - name: Code Coverage Report
-        uses: irongut/CodeCoverageSummary@51cc3a756ddcd398d447c044c02cb6aa83fdae95 # v1.3.0
-        with:
-          filename: coverage.xml
-          badge: true
-          fail_below_min: false
-          format: markdown
-          hide_branch_rate: false
-          hide_complexity: true
-          indicators: true
-          output: both
-          thresholds: '80 90'
-
-      - name: Add Coverage PR Comment
-        uses: marocchino/sticky-pull-request-comment@52423e01640425a022ef5fd42c6fb5f633a02728  # v2.9.3
-        if: github.event_name == 'pull_request'
-        with:
-          recreate: true
-          path: code-coverage-results.md
+            })

.github/workflows/coverage_report.yml

@@ -0,0 +1,78 @@
+name: Comment on the pull request
+
+# read-write repo token
+# access to secrets
+on:
+  workflow_run:
+    workflows: ["Test and lint"]
+    types:
+      - completed
+
+jobs:
+  upload:
+    runs-on: ubuntu-latest
+    if: >
+      github.event.workflow_run.event == 'pull_request'
+    steps:
+      - name: Download PR number
+        uses: actions/download-artifact@v4
+        with:
+            pattern: pr
+            path: .
+            # merge only when files are named differently
+            github-token: ${{ secrets.GITHUB_TOKEN }}
+            run-id: ${{ github.event.workflow_run.id }}
+      - name: Extract PR number
+        id: pr_number
+        run: |
+          echo "PR number is:"
+          cat pr/NR
+          echo "pr_number=$(cat pr/NR)" >> $GITHUB_ENV
+      - uses: actions/checkout@v4
+        with:
+          persist-credentials: false
+      - name: Set up Python
+        uses: actions/setup-python@v5
+        with:
+          python-version: "3"
+      - name: Download coverage artifacts
+        uses: actions/download-artifact@v4
+        with:
+            pattern: .coverage_*
+            path: .
+            # merge only when files are named differently
+            merge-multiple: true
+            github-token: ${{ secrets.GITHUB_TOKEN }}
+            run-id: ${{ github.event.workflow_run.id }}
+      - name: Install dependencies
+        run: pip install coverage
+      - name: Combine coverage results
+        run: |
+          # List the files to see what we have
+          echo "Combining coverage files..."
+          ls -aR .coverage*
+          coverage combine .coverage*
+          echo "Creating coverage report..."
+          coverage report
+          coverage xml
+
+      - name: Code Coverage Report
+        uses: irongut/CodeCoverageSummary@51cc3a756ddcd398d447c044c02cb6aa83fdae95 # v1.3.0
+        with:
+          filename: coverage.xml
+          badge: true
+          fail_below_min: false
+          format: markdown
+          hide_branch_rate: false
+          hide_complexity: true
+          indicators: true
+          output: both
+          thresholds: '80 90'
+
+      - name: Add Coverage PR Comment
+        uses: marocchino/sticky-pull-request-comment@52423e01640425a022ef5fd42c6fb5f633a02728  # v2.9.3
+        if: github.event_name == 'pull_request'
+        with:
+          recreate: true
+          path: code-coverage-results.md
+          number: ${{ env.pr_number }}