ci: Automatically tag released PRs

.github/workflows/release-plz.yml

@@ -27,3 +27,32 @@ jobs:
         env:
           GITHUB_TOKEN: ${{ secrets.RELEASE_PLZ_TOKEN }}
           CARGO_REGISTRY_TOKEN: ${{ secrets.CARGO_REGISTRY_TOKEN }}
+      - name: Tag released PRs
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+          RELEASES: ${{ steps.release-plz.outputs.releases }}
+        run: |
+          set -e
+
+          # Iterate over released packages and add a label to the PRs
+          # shipped with the release.
+          for release in $(echo "$RELEASES" | jq -r -c '.[]'); do
+              package_name=$(echo "$release" | jq -r '.package_name')
+              version=$(echo "$release" | jq -r '.version')
+              prs_length=$(echo "$release" | jq '.prs | length')
+              if [ "$prs_length" -gt 0 ]; then
+                  # Create label.
+                  # Use `--force` to overwrite the label,
+                  # so that the command does not fail if the label already exists.
+                  label="released:$package_name-$version"
+                  echo "Creating label $label"
+                  gh label create $label --color BFD4F2 --force
+                  for pr in $(echo "$release" | jq -r -c '.prs[]'); do
+                      pr_number=$(echo "$pr" | jq -r '.number')
+                      echo "Adding label $label to PR #$pr_number"
+                      gh pr edit $pr_number --add-label $label
+                  done
+              else
+                  echo "No PRs found for package $package_name"
+              fi
+          done