Avoid duplicate CI runs for PR branches

Signed-off-by: lucarlig <luca.carlig@ibm.com>

Author: lucarlig

.github/workflows/ci-rust-python-package.yaml

@@ -21,11 +21,55 @@ on:
       - ".github/workflows/ci-rust-python-package.yaml"
       - ".github/workflows/release-rust-python-package.yaml"
 
+concurrency:
+  group: ci-rust-python-package-${{ github.event.pull_request.head.repo.full_name || github.repository }}-${{ github.head_ref || github.ref_name }}
+  cancel-in-progress: true
+
 permissions:
   contents: read
+  pull-requests: read
 
 jobs:
+  dedupe:
+    runs-on: ubuntu-latest
+    outputs:
+      should_run: ${{ steps.decide.outputs.should_run }}
+    steps:
+      - id: decide
+        shell: bash
+        env:
+          EVENT_NAME: ${{ github.event_name }}
+          REF_NAME: ${{ github.ref_name }}
+          REF_TYPE: ${{ github.ref_type }}
+          REPOSITORY: ${{ github.repository }}
+          GITHUB_TOKEN: ${{ github.token }}
+        run: |
+          set -euo pipefail
+          should_run=true
+
+          if [[ "${EVENT_NAME}" == "push" && "${REF_TYPE}" == "branch" ]]; then
+            head="${REPOSITORY%%/*}:${REF_NAME}"
+            prs_json=$(curl -fsSL \
+              -H "Authorization: Bearer ${GITHUB_TOKEN}" \
+              -H "Accept: application/vnd.github+json" \
+              "https://api.github.com/repos/${REPOSITORY}/pulls?state=open&head=${head}")
+            open_pr_count=$(JSON_INPUT="$prs_json" python3 - <<'PY'
+          import json
+          import os
+
+          print(len(json.loads(os.environ["JSON_INPUT"])))
+          PY
+            )
+            if [[ "${open_pr_count}" != "0" ]]; then
+              should_run=false
+            fi
+          fi
+
+          echo "should_run=${should_run}" >> "$GITHUB_OUTPUT"
+
   validate-and-detect:
+    needs: dedupe
+    if: needs.dedupe.outputs.should_run == 'true'
     runs-on: ubuntu-latest
     outputs:
       plugins: ${{ steps.detect.outputs.plugins }}
@@ -76,8 +120,8 @@ jobs:
           fi
 
   build-test:
-    needs: validate-and-detect
-    if: needs.validate-and-detect.outputs.has_plugins == 'true'
+    needs: [dedupe, validate-and-detect]
+    if: needs.dedupe.outputs.should_run == 'true' && needs.validate-and-detect.outputs.has_plugins == 'true'
     strategy:
       fail-fast: false
       matrix:

tests/test_plugin_catalog.py

@@ -338,7 +338,12 @@ def test_ci_workflow_uses_make_targets_for_plugin_checks(self) -> None:
         workflow = (
             REPO_ROOT / ".github" / "workflows" / "ci-rust-python-package.yaml"
         ).read_text()
+        self.assertIn("concurrency:", workflow)
+        self.assertIn("cancel-in-progress: true", workflow)
+        self.assertIn("github.head_ref || github.ref_name", workflow)
         self.assertIn("pull_request:\n    branches: [main]", workflow)
+        self.assertIn('pulls?state=open&head=', workflow)
+        self.assertIn('if: needs.dedupe.outputs.should_run == \'true\'', workflow)
         self.assertNotIn("Validate plugin catalog", workflow)
         self.assertIn("run: make ci", workflow)
         self.assertIn("shell: bash", workflow)