Handle merge conflicts with manual resolution workflow (#8)

Phlogistique · claude · web-flow · commit 039371dfdbe6 · 2025-12-25T10:37:06.000+01:00
* Add automatic continuation after manual conflict resolution

When a PR has a conflict that requires manual resolution:
1. The action adds the 'autorestack-needs-conflict-resolution' label
2. User manually resolves the conflict and pushes
3. The push triggers a 'synchronize' event
4. The workflow detects the label and triggers the continuation job
5. The action removes the label, posts confirmation, and updates child PRs

This ensures the PR stack continues to be updated even after manual
intervention is required.

* Update README with conflict resolution continuation docs

Document the automatic continuation feature after manual conflict
resolution, including the updated workflow configuration with the
synchronize trigger and continuation job.

---------

Co-authored-by: Claude &lt;noreply@anthropic.com&gt;
diff --git a/.github/workflows/update-pr-stack.yml b/.github/workflows/update-pr-stack.yml
@@ -2,7 +2,7 @@ name: Optimized Recursive Update of PR Stack on Squash Merge
 
 on:
   pull_request:
-    types: [closed]
+    types: [closed, synchronize]
 
 permissions:
   contents: write
@@ -11,7 +11,7 @@ permissions:
 
 jobs:
   update-pr-stack:
-    if: github.event.pull_request.merged == true && github.event.pull_request.merge_commit_sha != ''
+    if: github.event.action == 'closed' && github.event.pull_request.merged == true && github.event.pull_request.merge_commit_sha != ''
     runs-on: ubuntu-latest
     steps:
       - name: Checkout repository
@@ -23,3 +23,19 @@ jobs:
         uses: ./
         with:
           github-token: ${{ secrets.GITHUB_TOKEN }}
+
+  continue-after-conflict-resolution:
+    if: github.event.action == 'synchronize' && contains(github.event.pull_request.labels.*.name, 'autorestack-needs-conflict-resolution')
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v3
+        with:
+          fetch-depth: 0
+
+      - name: Continue PR stack update after conflict resolution
+        uses: ./
+        with:
+          github-token: ${{ secrets.GITHUB_TOKEN }}
+          mode: conflict-resolved
+          pr-branch: ${{ github.event.pull_request.head.ref }}
diff --git a/README.md b/README.md
@@ -23,6 +23,21 @@ This action tries to fix that in a transparent way. Install it, and hopefully th
 5. Updates each PR's base branch to point to trunk
 6. Force-pushes updated branches and deletes the merged branch
 
+### Conflict handling
+
+When a merge conflict occurs during the automatic update:
+
+1. The action posts a comment on the affected PR with instructions for manual resolution
+2. Adds a `autorestack-needs-conflict-resolution` label to the PR
+3. Updates the PR's base branch (but doesn't push the conflicted state)
+
+After you manually resolve the conflict and push:
+
+1. The push triggers the `synchronize` event
+2. The action detects the conflict label and removes it
+3. Posts a confirmation comment
+4. Continues updating any dependent PRs in the stack
+
 ---
 
 ### Setup
@@ -33,7 +48,7 @@ name: Update Stacked PRs on Squash Merge
 
 on:
   pull_request:
-    types: [closed]
+    types: [closed, synchronize]
 
 permissions:
   contents: write
@@ -42,7 +57,7 @@ permissions:
 
 jobs:
   update-pr-stack:
-    if: github.event.pull_request.merged == true && github.event.pull_request.merge_commit_sha != ''
+    if: github.event.action == 'closed' && github.event.pull_request.merged == true && github.event.pull_request.merge_commit_sha != ''
     runs-on: ubuntu-latest
     steps:
       - name: Checkout repository
@@ -52,14 +67,30 @@ jobs:
 
       - name: Update PR stack
         uses: Phlogistique/autorestack-action@main
-        env:
-          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+        with:
+          github-token: ${{ secrets.GITHUB_TOKEN }}
+
+  continue-after-conflict-resolution:
+    if: github.event.action == 'synchronize' && contains(github.event.pull_request.labels.*.name, 'autorestack-needs-conflict-resolution')
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v3
+        with:
+          fetch-depth: 0
+
+      - name: Continue PR stack update
+        uses: Phlogistique/autorestack-action@main
+        with:
+          github-token: ${{ secrets.GITHUB_TOKEN }}
+          mode: conflict-resolved
+          pr-branch: ${{ github.event.pull_request.head.ref }}
 ```
 
 ### Notes
 
 * Currently only supports squash merges
-* If a merge hits a conflict, you'll need to resolve it manually
+* If a merge hits a conflict, you'll need to resolve it manually; pushing the resolution automatically continues the stack update
 * Very large stacks might hit GitHub rate limits
 
 ---
diff --git a/action.yml b/action.yml
@@ -7,6 +7,14 @@ inputs:
     description: 'GitHub token for API access'
     required: true
     default: ${{ github.token }}
+  mode:
+    description: 'Action mode: squash-merge (after PR merge) or conflict-resolved (after manual resolution)'
+    required: false
+    default: 'squash-merge'
+  pr-branch:
+    description: 'The PR branch that was pushed (required for conflict-resolved mode)'
+    required: false
+    default: ''
 
 runs:
   using: 'composite'
@@ -19,9 +27,11 @@ runs:
         GIT_AUTHOR_EMAIL: github-actions@github.com
         GIT_COMMITTER_NAME: github-actions
         GIT_COMMITTER_EMAIL: github-actions@github.com
+        ACTION_MODE: ${{ inputs.mode }}
         SQUASH_COMMIT: ${{ github.event.pull_request.merge_commit_sha }}
         MERGED_BRANCH: ${{ github.event.pull_request.head.ref }}
         TARGET_BRANCH: ${{ github.event.pull_request.base.ref }}
+        PR_BRANCH: ${{ inputs.pr-branch }}
       run: ${{ github.action_path }}/update-pr-stack.sh
 
 branding:
diff --git a/tests/test_e2e.sh b/tests/test_e2e.sh
@@ -67,11 +67,13 @@
 #   - Conflict label "autorestack-needs-conflict-resolution" exists on PR3
 #   - feature3 branch was NOT updated (still at pre-conflict SHA)
 #
-# Manual Conflict Resolution (Steps 12-13):
+# Manual Conflict Resolution (Steps 12-14):
 #   - Test simulates user resolving the conflict manually
 #   - Merge main into feature3, resolve conflict (keep feature3's changes)
 #   - Push the resolved branch
-#   - Verify the resolved state is correct
+#   - The push triggers the 'synchronize' event on PR3
+#   - The action detects the conflict label and removes it
+#   - Verify the label is removed and resolution comment is posted
 #
 # =============================================================================
 set -e # Exit immediately if a command exits with a non-zero status.
@@ -163,6 +165,98 @@ merge_pr_with_retry() {
     return 1
 }
 
+wait_for_synchronize_workflow() {
+    local pr_number=$1 # PR number that was updated
+    local branch_name=$2 # The branch name that was pushed
+    local expected_conclusion=${3:-success} # Expected conclusion (success, failure, etc.)
+    local max_attempts=20 # ~7 mins max wait
+    local attempt=0
+    local target_run_id=""
+    local start_time=$(date +%s)
+
+    echo >&2 "Waiting for workflow '$WORKFLOW_FILE' triggered by synchronize event on PR #$pr_number (branch $branch_name)..."
+
+    while [[ $attempt -lt $max_attempts ]]; do
+        sleep_time=$(( (attempt + 1) * 2 ))
+        echo >&2 "Attempt $((attempt + 1))/$max_attempts: Checking for workflow run..."
+
+        if [[ -z "$target_run_id" ]]; then
+            echo >&2 "Searching for the specific workflow run..."
+            # List recent runs for the workflow triggered by pull_request event
+            candidate_run_ids=$(log_cmd gh run list \
+                --repo "$REPO_FULL_NAME" \
+                --workflow "$WORKFLOW_FILE" \
+                --event pull_request \
+                --limit 15 \
+                --json databaseId,createdAt --jq '.[] | select(.createdAt >= "'$(date -d "@$start_time" -Iseconds 2>/dev/null || date -r $start_time +%Y-%m-%dT%H:%M:%S)'") | .databaseId' || echo "")
+
+            if [[ -z "$candidate_run_ids" ]]; then
+                echo >&2 "No recent '$WORKFLOW_FILE' runs found since start. Sleeping $sleep_time seconds."
+                sleep $sleep_time
+                attempt=$((attempt + 1))
+                continue
+            fi
+
+            echo >&2 "Found candidate run IDs: $candidate_run_ids. Checking runs..."
+            for run_id in $candidate_run_ids; do
+                echo >&2 "Checking candidate run ID: $run_id"
+                run_info=$(log_cmd gh run view "$run_id" --repo "$REPO_FULL_NAME" --json headBranch,jobs || echo "{}")
+
+                run_head_branch=$(echo "$run_info" | jq -r '.headBranch // ""')
+                # Check if this run has the continue-after-conflict-resolution job
+                has_continue_job=$(echo "$run_info" | jq -r '.jobs[] | select(.name == "continue-after-conflict-resolution") | .name' || echo "")
+
+                echo >&2 "  Run head branch: $run_head_branch, has continue job: $has_continue_job"
+
+                if [[ "$run_head_branch" == "$branch_name" && -n "$has_continue_job" ]]; then
+                    echo >&2 "Found matching workflow run ID: $run_id (synchronize with continue job)"
+                    target_run_id="$run_id"
+                    break
+                fi
+            done
+        fi
+
+        if [[ -z "$target_run_id" ]]; then
+            echo >&2 "Target workflow run not found among recent runs. Sleeping $sleep_time seconds."
+            sleep $sleep_time
+            attempt=$((attempt + 1))
+            continue
+        fi
+
+        # Monitor the identified target run
+        echo >&2 "Monitoring workflow run ID: $target_run_id"
+        run_info=$(log_cmd gh run view "$target_run_id" --repo "$REPO_FULL_NAME" --json status,conclusion)
+        run_status=$(echo "$run_info" | jq -r '.status')
+        run_conclusion=$(echo "$run_info" | jq -r '.conclusion')
+
+        echo >&2 "Workflow run $target_run_id status: $run_status, conclusion: $run_conclusion"
+
+        if [[ "$run_status" == "completed" ]]; then
+            if [[ "$run_conclusion" == "$expected_conclusion" ]]; then
+                echo >&2 "Workflow $target_run_id completed with expected conclusion: $run_conclusion."
+                return 0
+            else
+                echo >&2 "Workflow $target_run_id completed with unexpected conclusion: $run_conclusion (expected: $expected_conclusion)"
+                log_cmd gh run view "$target_run_id" --repo "$REPO_FULL_NAME" --log || echo >&2 "Could not fetch logs for run $target_run_id"
+                return 1
+            fi
+        elif [[ "$run_status" == "queued" || "$run_status" == "in_progress" || "$run_status" == "waiting" ]]; then
+            echo >&2 "Workflow $target_run_id is $run_status. Sleeping $sleep_time seconds."
+        else
+            echo >&2 "Workflow $target_run_id has unexpected status: $run_status. Conclusion: $run_conclusion"
+            log_cmd gh run view "$target_run_id" --repo "$REPO_FULL_NAME" --log || echo >&2 "Could not fetch logs for run $target_run_id"
+            return 1
+        fi
+
+        sleep $sleep_time
+        attempt=$((attempt + 1))
+    done
+
+    echo >&2 "Timeout waiting for synchronize workflow run to complete."
+    gh run list --repo "$REPO_FULL_NAME" --workflow "$WORKFLOW_FILE" --limit 10 || echo >&2 "Could not list recent runs."
+    return 1
+}
+
 wait_for_workflow() {
     local pr_number=$1 # PR number that was merged
     local merged_branch_name=$2 # The head branch name of the merged PR (unused now, but kept for context)
@@ -303,14 +397,15 @@ cat > .github/workflows/"$WORKFLOW_FILE" <<EOF
 name: Update Stacked PRs on Squash Merge (E2E Test)
 on:
   pull_request:
-    types: [closed]
+    types: [closed, synchronize]
 permissions:
   contents: write
   pull-requests: write
 jobs:
   update-pr-stack:
     # Only run on actual squash merges initiated by the test script
     if: |
+      github.event.action == 'closed' &&
       github.event.pull_request.merged == true &&
       github.event.pull_request.merge_commit_sha != ''
     runs-on: ubuntu-latest
@@ -327,6 +422,24 @@ jobs:
         uses: ./
         with:
           github-token: \${{ secrets.GITHUB_TOKEN }}
+  continue-after-conflict-resolution:
+    # Run when a PR with the conflict label is updated (user pushed conflict resolution)
+    if: |
+      github.event.action == 'synchronize' &&
+      contains(github.event.pull_request.labels.*.name, 'autorestack-needs-conflict-resolution')
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v4
+        with:
+          fetch-depth: 0
+          token: \${{ secrets.GITHUB_TOKEN }}
+      - name: Continue PR stack update after conflict resolution
+        uses: ./
+        with:
+          github-token: \${{ secrets.GITHUB_TOKEN }}
+          mode: conflict-resolved
+          pr-branch: \${{ github.event.pull_request.head.ref }}
 EOF
 
 log_cmd git add action.yml update-pr-stack.sh command_utils.sh .github/workflows/"$WORKFLOW_FILE"
@@ -610,8 +723,44 @@ fi
 log_cmd git push origin feature3
 echo >&2 "Pushed resolved feature3."
 
-# 13. Verify conflict resolution
-echo >&2 "13. Verifying conflict resolution..."
+# 13. Wait for continuation workflow triggered by push
+echo >&2 "13. Waiting for continuation workflow after conflict resolution push..."
+if ! wait_for_synchronize_workflow "$PR3_NUM" "feature3" "success"; then
+    echo >&2 "Continuation workflow for feature3 conflict resolution did not complete successfully."
+    exit 1
+fi
+
+# 14. Verify continuation workflow effects
+echo >&2 "14. Verifying continuation workflow effects..."
+
+# Verify conflict label was removed from PR3
+echo >&2 "Checking that conflict label was removed from PR #$PR3_NUM..."
+sleep 5 # Give GitHub time to process
+CONFLICT_LABEL_AFTER=$(log_cmd gh pr view "$PR3_URL" --repo "$REPO_FULL_NAME" --json labels --jq '.labels[] | select(.name == "autorestack-needs-conflict-resolution") | .name')
+if [[ -z "$CONFLICT_LABEL_AFTER" ]]; then
+    echo >&2 "✅ Verification Passed: Conflict label was removed from PR #$PR3_NUM."
+else
+    echo >&2 "❌ Verification Failed: Conflict label still exists on PR #$PR3_NUM."
+    exit 1
+fi
+
+# Verify resolution acknowledgement comment exists on PR3
+echo >&2 "Checking for resolution acknowledgement comment on PR #$PR3_NUM..."
+RESOLUTION_COMMENT=$(log_cmd gh pr view "$PR3_URL" --repo "$REPO_FULL_NAME" --json comments --jq '.comments[] | select(.body | contains("Conflict resolved")) | .body')
+if [[ -n "$RESOLUTION_COMMENT" ]]; then
+    echo >&2 "✅ Verification Passed: Resolution acknowledgement comment found on PR #$PR3_NUM."
+else
+    echo >&2 "❌ Verification Failed: Resolution acknowledgement comment not found on PR #$PR3_NUM."
+    echo >&2 "--- Comments on PR #$PR3_NUM ---"
+    gh pr view "$PR3_URL" --repo "$REPO_FULL_NAME" --json comments --jq '.comments[].body' || echo "Failed to get comments"
+    echo >&2 "-----------------------------"
+    exit 1
+fi
+
+echo >&2 "--- Continuation Workflow Test Completed Successfully ---"
+
+# 15. Verify conflict resolution (content checks)
+echo >&2 "15. Verifying conflict resolution content..."
 # Fetch the latest state again
 log_cmd git fetch origin
 log_cmd git checkout feature3
@@ -653,9 +802,6 @@ else
     exit 1
 fi
 
-# Optional: Verify the conflict label could be removed (manual step usually)
-# We won't automate label removal check as the action doesn't do it.
-
 echo >&2 "--- Conflict Scenario Test Completed Successfully ---"
 
 
diff --git a/update-pr-stack.sh b/update-pr-stack.sh
