refs or cleanup

Author: SimonCropp

.github/workflows/merge-dependabot.yml

@@ -25,6 +25,9 @@ jobs:
       # Dependabot records the update type in its commit message metadata, for example
       # "update-type: version-update:semver-minor". A grouped bump lists one per dependency.
       # --match-head-commit refuses the merge if the branch moved after this build ran.
+      # A bump that conflicts with main (an earlier bump merged an adjacent line) is skipped:
+      # Dependabot rebases it, the rebase reruns Build, and that run triggers this workflow again.
+      # GitHub computes mergeability lazily, so UNKNOWN is retried briefly.
       - name: Merge when the bump is minor or patch
         env:
           GH_TOKEN: ${{ github.token }}
@@ -42,4 +45,13 @@ jobs:
             echo "::warning::No open pull request for $BRANCH"
             exit 0
           fi
+          for attempt in 1 2 3 4 5 6; do
+            mergeable=$(gh pr view "$pr" --json mergeable --jq '.mergeable')
+            [ "$mergeable" != "UNKNOWN" ] && break
+            sleep 5
+          done
+          if [ "$mergeable" = "CONFLICTING" ]; then
+            echo "::warning::Pull request #$pr conflicts with the base branch, leaving for Dependabot to rebase"
+            exit 0
+          fi
           gh pr merge "$pr" --squash --match-head-commit "$HEAD_SHA"