fix(ci): keep enqueue across review chatter

.github/workflows/auto-merge.yaml

@@ -7,10 +7,6 @@ on:
   pull_request_review:
     types: [submitted]
 
-concurrency:
-  group: enable-auto-merge-${{ github.event.pull_request.number }}
-  cancel-in-progress: true
-
 permissions:
   contents: read
 
@@ -24,6 +20,9 @@ jobs:
       && github.event.pull_request.user.login != 'renovate[bot]'
       && (github.event_name != 'pull_request_review' || github.event.review.state == 'approved')
     runs-on: ubuntu-latest
+    concurrency:
+      group: enable-auto-merge-${{ github.event.pull_request.number }}
+      cancel-in-progress: true
     steps:
       - name: Mint seahaven-bot token
         id: app-token
@@ -42,13 +41,33 @@ jobs:
           PR_NODE_ID: ${{ github.event.pull_request.node_id }}
         run: |
           set -euo pipefail
-          in_queue="$(gh api graphql -f query='query($id:ID!) { node(id:$id) { ... on PullRequest { isInMergeQueue } } }' -f id="$PR_NODE_ID" --jq '.data.node.isInMergeQueue')"
-          if [ "$in_queue" = "true" ]; then
+          BOT_LOGIN='seahaven-bot[bot]'
+          GQL_STATE="query(\$id:ID!) { node(id:\$id) { ... on PullRequest { isInMergeQueue autoMergeRequest { mergeMethod enabledBy { login } } } } }"
+
+          pr_json() {
+            gh api graphql -f query="$GQL_STATE" -f id="$PR_NODE_ID" "$@"
+          }
+
+          in_queue() {
+            pr_json --jq '.data.node.isInMergeQueue'
+          }
+
+          enabled_by() {
+            pr_json --jq -r '.data.node.autoMergeRequest.enabledBy.login // ""'
+          }
+
+          armed_as_bot() {
+            by="$(enabled_by)"
+            [ "$by" = "$BOT_LOGIN" ] || [ "$by" = "seahaven-bot" ]
+          }
+
+          if [ "$(in_queue)" = "true" ]; then
             echo "already in merge queue"
             exit 0
           fi
+
           set +e
-          out="$(gh api graphql -f query='mutation($id:ID!) { enqueuePullRequest(input:{pullRequestId:$id}) { mergeQueueEntry { state } } }' -f id="$PR_NODE_ID" 2>&1)"
+          out="$(gh api graphql -f query="mutation(\$id:ID!) { enqueuePullRequest(input:{pullRequestId:\$id}) { mergeQueueEntry { state } } }" -f id="$PR_NODE_ID" 2>&1)"
           status=$?
           set -e
           if [ "$status" -eq 0 ]; then
@@ -56,13 +75,37 @@ jobs:
             exit 0
           fi
           echo "$out"
+
           # Re-arm as seahaven-bot. A leftover GITHUB_TOKEN auto-merge would
-          # enqueue without starting merge_group.
-          gh pr merge "$PR" --repo "$REPO" --disable-auto || true
-          if ! gh pr merge "$PR" --repo "$REPO" --auto; then
-            if [ "$(gh pr view "$PR" --repo "$REPO" --json autoMergeRequest --jq '.autoMergeRequest != null')" = "true" ]; then
-              echo "auto-merge already enabled"
-              exit 0
+          # enqueue without starting merge_group. Do not treat an unknown
+          # autoMergeRequest as success.
+          by="$(enabled_by)"
+          if [ -n "$by" ]; then
+            set +e
+            disable_out="$(gh pr merge "$PR" --repo "$REPO" --disable-auto 2>&1)"
+            set -e
+            echo "$disable_out"
+            by="$(enabled_by)"
+            if [ -n "$by" ]; then
+              echo "failed to disable auto-merge (enabledBy=$by)"
+              exit 1
             fi
-            exit 1
           fi
+
+          set +e
+          arm_out="$(gh pr merge "$PR" --repo "$REPO" --auto 2>&1)"
+          arm_status=$?
+          set -e
+          printf '%s\n' "$arm_out"
+
+          if [ "$(in_queue)" = "true" ]; then
+            echo "in merge queue"
+            exit 0
+          fi
+          if armed_as_bot; then
+            echo "auto-merge armed as seahaven-bot"
+            exit 0
+          fi
+          by="$(enabled_by)"
+          echo "auto-merge not armed as seahaven-bot (enabledBy=${by:-none} arm_status=$arm_status)"
+          exit 1