Merge #6758: feat: enhance conflict prediction workflow with PR comments

538d88d fix: add UTF-8 encoding to file open operation (pasta)
e0515b9 fix: use dynamic repository reference and update checkout action (pasta)
2758785 cleanup: remove debug logging now that issues are resolved (pasta)
8b3c439 fix: improve conflict detection by checking for partial text or X icon (pasta)
5a853f2 debug: add more diagnostics for response text analysis (pasta)
a7be4bb debug: add more detailed logging for merge check failures (pasta)
75c21e6 fix: make repository configurable using GITHUB_REPOSITORY env var (pasta)
4668cb7 fix: handle missing PR data gracefully in conflict checker (pasta)
3180c2d feat: enhance conflict prediction workflow with PR comments (pasta)

Pull request description:

  ## Summary

  This PR enhances the conflict prediction workflow to automatically post comments on pull requests when potential merge conflicts are detected with other open PRs.

  ## Changes

  ### 1. Enhanced Python Script (`handle_potential_conflicts.py`)
  - Added GitHub Actions output functionality to pass conflict data to the workflow
  - Made repository configurable using `GITHUB_REPOSITORY` environment variable (supports testing on forks)
  - Improved error handling to gracefully skip PRs that fail to fetch
  - Fixed conflict detection to work with current GitHub HTML responses
  - Added formatted markdown output for PR comments

  ### 2. Updated Workflow (`predict-conflicts.yml`)
  - Added PR comment posting using `mshick/add-pr-comment@v2`
  - Comments are updateable (sticky) using `message-id` to prevent duplicates
  - Shows list of conflicting PRs with links when conflicts exist
  - Removes/updates comment when conflicts are resolved
  - Maintains original failure behavior

  ### 3. Bug Fixes
  - Fixed KeyError when PR API responses don't have expected fields
  - Improved HTML response parsing for merge conflict detection
  - Added support for partial text matching ("Can't automatic") and icon detection ("octicon octicon-x")

  ## Example Comment Output

  When conflicts are detected:
  ```
  ## ⚠️ Potential Merge Conflicts Detected

  This PR has potential conflicts with the following open PRs:

  - #1234 - [PR Title](#1234)
  - #5678 - [Another PR Title](#5678)

  Please coordinate with the authors of these PRs to avoid merge conflicts.
  ```

  When no conflicts exist:
  ```
  ## ✅ No Merge Conflicts Detected

  This PR currently has no conflicts with other open PRs.
  ```

  ## Testing

  This has been tested on the PastaPastaPasta/dash fork with multiple test PRs to verify:
  - Conflict detection works correctly
  - Comments are posted and updated properly
  - No duplicate comments are created
  - Works with forked repositories

  ## Benefits

  - Better visibility of potential merge conflicts early in the review process
  - Helps maintainers and contributors coordinate on conflicting changes
  - Reduces merge conflicts and rebasing work
  - Automatic updates keep the information current

ACKs for top commit:
  UdjinM6:
    utACK 538d88d

Tree-SHA512: d687f3aba8c8a48a404257fa39ddd0826a806616f3bd4e374f797ebe8061eccb3b80012d64405f2635acffea04101754446f378a02a887956e0aa78ca01a2873

Author: PastaPastaPasta

.github/workflows/handle_potential_conflicts.py

@@ -19,59 +19,166 @@
 """
 
 import sys
+import os
+import json
+import uuid
 import requests
 
 # need to install via pip
-import hjson
+try:
+    import hjson
+except ImportError:
+    print("Error: hjson module not found. Please install it with: pip install hjson", file=sys.stderr)
+    sys.exit(1)
 
 def get_pr_json(pr_num):
-    return requests.get(f'https://api.github.com/repos/dashpay/dash/pulls/{pr_num}').json()
+    # Get repository from environment or default to dashpay/dash
+    repo = os.environ.get('GITHUB_REPOSITORY', 'dashpay/dash')
+
+    try:
+        response = requests.get(f'https://api.github.com/repos/{repo}/pulls/{pr_num}')
+        response.raise_for_status()
+        pr_data = response.json()
+
+        # Check if we got an error response
+        if 'message' in pr_data and 'head' not in pr_data:
+            print(f"Warning: GitHub API error for PR {pr_num}: {pr_data.get('message', 'Unknown error')}", file=sys.stderr)
+            return None
+
+        return pr_data
+    except requests.RequestException as e:
+        print(f"Warning: Error fetching PR {pr_num}: {e}", file=sys.stderr)
+        return None
+    except json.JSONDecodeError as e:
+        print(f"Warning: Error parsing JSON for PR {pr_num}: {e}", file=sys.stderr)
+        return None
+
+def set_github_output(name, value):
+    """Set GitHub Actions output"""
+    if 'GITHUB_OUTPUT' not in os.environ:
+        print(f"Warning: GITHUB_OUTPUT not set, skipping output: {name}={value}", file=sys.stderr)
+        return
+
+    try:
+        with open(os.environ['GITHUB_OUTPUT'], 'a', encoding='utf8') as f:
+            # For multiline values, use the delimiter syntax
+            if '\n' in str(value):
+                delimiter = f"EOF_{uuid.uuid4()}"
+                f.write(f"{name}<<{delimiter}\n{value}\n{delimiter}\n")
+            else:
+                f.write(f"{name}={value}\n")
+    except IOError as e:
+        print(f"Error writing to GITHUB_OUTPUT: {e}", file=sys.stderr)
 
 def main():
     if len(sys.argv) != 2:
         print(f'Usage: {sys.argv[0]} <conflicts>', file=sys.stderr)
         sys.exit(1)
 
-    input = sys.argv[1]
-    print(input)
-    j_input = hjson.loads(input)
-    print(j_input)
+    conflict_input = sys.argv[1]
 
+    try:
+        j_input = hjson.loads(conflict_input)
+    except Exception as e:
+        print(f"Error parsing input JSON: {e}", file=sys.stderr)
+        sys.exit(1)
+
+    # Validate required fields
+    if 'pull_number' not in j_input:
+        print("Error: 'pull_number' field missing from input", file=sys.stderr)
+        sys.exit(1)
+    if 'conflictPrs' not in j_input:
+        print("Error: 'conflictPrs' field missing from input", file=sys.stderr)
+        sys.exit(1)
 
     our_pr_num = j_input['pull_number']
-    our_pr_label = get_pr_json(our_pr_num)['head']['label']
-    conflictPrs = j_input['conflictPrs']
+    our_pr_json = get_pr_json(our_pr_num)
+
+    if our_pr_json is None:
+        print(f"Error: Failed to fetch PR {our_pr_num}", file=sys.stderr)
+        sys.exit(1)
+
+    if 'head' not in our_pr_json or 'label' not in our_pr_json['head']:
+        print(f"Error: Invalid PR data structure for PR {our_pr_num}", file=sys.stderr)
+        sys.exit(1)
+
+    our_pr_label = our_pr_json['head']['label']
+    conflict_prs = j_input['conflictPrs']
 
     good = []
     bad = []
+    conflict_details = []
+
+    for conflict in conflict_prs:
+        if 'number' not in conflict:
+            print("Warning: Skipping conflict entry without 'number' field", file=sys.stderr)
+            continue
 
-    for conflict in conflictPrs:
         conflict_pr_num = conflict['number']
-        print(conflict_pr_num)
 
         conflict_pr_json = get_pr_json(conflict_pr_num)
+
+        if conflict_pr_json is None:
+            print(f"Warning: Failed to fetch PR {conflict_pr_num}, skipping", file=sys.stderr)
+            continue
+
+        if 'head' not in conflict_pr_json or 'label' not in conflict_pr_json['head']:
+            print(f"Warning: Invalid PR data structure for PR {conflict_pr_num}, skipping", file=sys.stderr)
+            continue
+
         conflict_pr_label = conflict_pr_json['head']['label']
-        print(conflict_pr_label)
 
-        if conflict_pr_json['mergeable_state'] == "dirty":
-            print(f'{conflict_pr_num} needs rebase. Skipping conflict check')
+        if conflict_pr_json.get('mergeable_state') == "dirty":
+            print(f'PR #{conflict_pr_num} needs rebase. Skipping conflict check', file=sys.stderr)
             continue
 
-        if conflict_pr_json['draft']:
-            print(f'{conflict_pr_num} is a draft. Skipping conflict check')
+        if conflict_pr_json.get('draft', False):
+            print(f'PR #{conflict_pr_num} is a draft. Skipping conflict check', file=sys.stderr)
+            continue
+
+        # Get repository from environment
+        repo = os.environ.get('GITHUB_REPOSITORY', 'dashpay/dash')
+        merge_check_url = f'https://github.com/{repo}/branches/pre_mergeable/{our_pr_label}...{conflict_pr_label}'
+
+        try:
+            pre_mergeable = requests.get(merge_check_url)
+            pre_mergeable.raise_for_status()
+        except requests.RequestException as e:
+            print(f"Error checking mergeability for PR {conflict_pr_num}: {e}", file=sys.stderr)
             continue
 
-        pre_mergeable = requests.get(f'https://github.com/dashpay/dash/branches/pre_mergeable/{our_pr_label}...{conflict_pr_label}')
         if "These branches can be automatically merged." in pre_mergeable.text:
             good.append(conflict_pr_num)
-        elif "Can’t automatically merge" in pre_mergeable.text:
+        elif "Can't automatic" in pre_mergeable.text or "octicon octicon-x" in pre_mergeable.text:
+            # Check for partial text or the X icon which indicates conflicts
             bad.append(conflict_pr_num)
+            conflict_details.append({
+                'number': conflict_pr_num,
+                'title': conflict_pr_json.get('title', 'Unknown'),
+                'url': conflict_pr_json.get('html_url', f'https://github.com/{repo}/pull/{conflict_pr_num}')
+            })
+        else:
+            print(f"Warning: Unexpected response for PR {conflict_pr_num} mergeability check. URL: {pre_mergeable.url}", file=sys.stderr)
+
+    print(f"Not conflicting PRs: {good}", file=sys.stderr)
+    print(f"Conflicting PRs: {bad}", file=sys.stderr)
+
+    # Set GitHub Actions outputs
+    if 'GITHUB_OUTPUT' in os.environ:
+        set_github_output('has_conflicts', 'true' if len(bad) > 0 else 'false')
+
+        # Format conflict details as markdown list
+        if conflict_details:
+            markdown_list = []
+            for conflict in conflict_details:
+                markdown_list.append(f"- #{conflict['number']} - [{conflict['title']}]({conflict['url']})")
+            conflict_markdown = '\n'.join(markdown_list)
+            set_github_output('conflict_details', conflict_markdown)
         else:
-            raise Exception("not mergeable or unmergable!")
+            set_github_output('conflict_details', '')
 
-    print("Not conflicting PRs: ", good)
+        set_github_output('conflicting_prs', ','.join(map(str, bad)))
 
-    print("Conflicting PRs: ", bad)
     if len(bad) > 0:
         sys.exit(1)
 

.github/workflows/predict-conflicts.yml

@@ -23,10 +23,38 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: check for potential conflicts
+        id: check_conflicts
         uses: PastaPastaPasta/potential-conflicts-checker-action@v0.1.10
         with:
           ghToken: "${{ secrets.GITHUB_TOKEN }}"
       - name: Checkout
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
       - name: validate potential conflicts
+        id: validate_conflicts
         run: pip3 install hjson && .github/workflows/handle_potential_conflicts.py "$conflicts"
+        continue-on-error: true
+      - name: Post conflict comment
+        if: steps.validate_conflicts.outputs.has_conflicts == 'true'
+        uses: mshick/add-pr-comment@v2
+        with:
+          message-id: conflict-prediction
+          message: |
+            ## ⚠️ Potential Merge Conflicts Detected
+
+            This PR has potential conflicts with the following open PRs:
+
+            ${{ steps.validate_conflicts.outputs.conflict_details }}
+
+            Please coordinate with the authors of these PRs to avoid merge conflicts.
+      - name: Remove conflict comment if no conflicts
+        if: steps.validate_conflicts.outputs.has_conflicts == 'false'
+        uses: mshick/add-pr-comment@v2
+        with:
+          message-id: conflict-prediction
+          message: |
+            ## ✅ No Merge Conflicts Detected
+
+            This PR currently has no conflicts with other open PRs.
+      - name: Fail if conflicts exist
+        if: steps.validate_conflicts.outputs.has_conflicts == 'true'
+        run: exit 1