Enhancement: Handle bot/app-authored PRs in conflict detection

[zkoppert]

Problem

When a detected conflict involves a PR authored by a bot or GitHub App (e.g., dependabot, renovate, github-actions[bot]), the current behavior creates awkward situations:

• Slack notifications mention bots with @bot-username, which doesn't make sense
• PR comments are posted on bot PRs asking them to coordinate with humans
• Issue reports list bots as people who need to coordinate
• Humans are asked to "coordinate with a bot", which is unclear guidance

Common bot scenarios

1. Dependabot PR conflicts with human PR - User needs to know their PR conflicts with a dependency update, but dependabot doesn't need to coordinate
2. Two bot PRs conflict (e.g., dependabot + renovate) - Neither bot can coordinate; humans should be aware but different handling needed
3. GitHub Actions bot PRs - Auto-generated PRs from workflows

Suggested solutions

Option 1: Filter out bot-authored PRs entirely

Add a configuration option to exclude PRs authored by bots:

env:
  EXCLUDE_BOT_PRS: "true"  # Skip any PR authored by a bot

Pros:

• Simple to implement and understand
• Reduces noise from dependency update conflicts

Cons:

• Users might want to know when their PR conflicts with a bot PR
• Loses visibility into important conflicts

Option 2: Asymmetric handling (recommended)

When a conflict involves one bot PR and one human PR:

• ✅ Notify the human author only (Slack, PR comment)
• ❌ Don't notify or comment on the bot PR
• ✅ Include conflict in reports/issues but note it's a bot PR

When both PRs are bots:

• ❌ Skip Slack notifications and PR comments
• ✅ Include in reports for visibility
• Note: "Both PRs are automated - review dependency/automation conflicts"

Option 3: Configurable bot list

Allow users to specify which bots to filter:

env:
  EXCLUDE_BOT_AUTHORS: "dependabot[bot],renovate[bot],github-actions[bot]"

Pros:

• Flexible - users control which bots to exclude
• Can exclude some bots but not others

Cons:

• Requires users to know bot usernames
• Maintenance burden to keep list updated

Option 4: Auto-detect using GitHub's bot flag

Use GitHub API's user.type field to detect bots automatically:

if pr.user.type == 'Bot':
    # Handle differently

Pros:

• No configuration needed
• Automatically handles all bots
• Future-proof for new bots

Cons:

• Relies on GitHub API correctly flagging bots

Recommended implementation

Combination of Option 2 + Option 4:

1. Auto-detect bots using GitHub API's user.type field
2. Apply asymmetric handling:
   • Human vs Bot conflict: Notify human only, skip bot notifications
   • Bot vs Bot conflict: Skip all notifications, include in reports with note
3. Add optional override config:

   EXCLUDE_BOT_PRS: "false"  # Default: include bot PRs but handle smartly
   TREAT_AS_BOTS: "custom-automation-user"  # Additional usernames to treat as bots

Implementation details

1. Add bot detection in pr_data.py:

   @dataclass
   class PRInfo:
       number: int
       title: str
       author: str
       is_bot: bool  # New field

2. Update conflict categorization in pr_conflict_detector.py:

   # After deduplication, categorize conflicts
   human_vs_human = [c for c in conflicts if not c.pr_a.is_bot and not c.pr_b.is_bot]
   human_vs_bot = [c for c in conflicts if c.pr_a.is_bot ^ c.pr_b.is_bot]
   bot_vs_bot = [c for c in conflicts if c.pr_a.is_bot and c.pr_b.is_bot]

3. Update notification modules:

   • slack_notify.py: Only send for human_vs_human, include human-only mention for human_vs_bot
   • pr_comment.py: Comment on human PR only for human_vs_bot conflicts
   • issue_writer.py: Include all conflicts but annotate bot PRs

4. Add summary output:

   Found 45 conflicts:
     - 30 human vs human conflicts
     - 12 human vs bot conflicts (notifying humans only)
     - 3 bot vs bot conflicts (report only, no notifications)
   

Additional considerations

• Bot PR comment wording: When commenting on a human PR about a bot conflict:

  ⚠️ Potential merge conflict detected

  This PR may conflict with automated PR #123 by dependabot[bot].

  Conflicting files:

  • package.json (lines 10-15)

  Consider rebasing after the bot PR merges, or merge your PR first if it takes precedence.

• Slack message wording for human vs bot:

  🤖 @alice - Your PR #456 may conflict with automated PR #123 by dependabot[bot]
  Files: package.json

Testing checklist

• Detect bot using GitHub API user.type field
• Human vs Human: Full notifications (existing behavior)
• Human vs Bot: Notify human only
• Bot vs Bot: Report only, no notifications
• Bot detection works for: dependabot, renovate, github-actions[bot]
• TREAT_AS_BOTS config allows manual bot list
• README updated with bot handling behavior
• Deduplication still works correctly with bot flags

Priority

Medium - This is a quality-of-life improvement that reduces notification noise and prevents awkward bot mentions, but doesn't break existing functionality.

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