feat: implement issue #647 — dev-lead: rebase requested via @mention (on-mention intent) fails to push — non-fast-forward, no force-with-lease

[don-petry]

Closes #647

Implemented by dev-lead agent. Please review.

Summary by CodeRabbit

Release Notes

• Bug Fixes
  • Auto-merge now detects when local branches diverge from upstream and retries failed pushes with force-with-lease
  • Protects against clobbering unseen remote changes during retry operations
  • Updates internal tracking state after successful force-push operations

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ℹ️ Review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: ASSERTIVE

Plan: Pro

Run ID: 2379dc39-aab4-4636-9753-b09a1f4ca56f

📥 Commits

Reviewing files that changed from the base of the PR and between 394cdd6 and 8da214d.

📒 Files selected for processing (2)

• scripts/lib/auto-merge.sh
• tests/dev-lead/unit/test_auto_merge.bats

📝 Walkthrough

Walkthrough

The PR enhances push_with_merge_guard in the auto-merge script to handle push failures caused by branch history rewrites. A new divergence detector identifies when a branch is both ahead and behind upstream, then retries the push once with --force-with-lease. After successful retry, the tracked HEAD SHA is refreshed. Comprehensive tests verify the retry logic, boundary conditions, and state updates.

Changes

Divergence Detection and Force-with-Lease Retry for Rebased Branches

Layer / File(s)

Summary

Divergence detection and force-with-lease retry mechanism scripts/lib/auto-merge.sh, tests/dev-lead/unit/test_auto_merge.bats

push_with_merge_guard introduces _branch_diverged_from_upstream to detect rewritten history (branch both ahead and behind upstream), documents the new behavior, and implements one-time retry logic using --force-with-lease when divergence is detected. On successful retry, _AM_HEAD_SHA is refreshed to match the new HEAD. Comprehensive tests validate the retry behavior on diverged branches, absence of force-push on non-diverged or fast-forward-only cases, proper handling when no upstream exists, early exit for closed PRs, and correct state refresh.

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~12 minutes

Possibly related PRs

• petry-projects/.github-private#453: Extended the same scripts/lib/auto-merge.sh with divergence detection and force-with-lease retry logic for rebased branches, including comprehensive unit tests for the new behavior.

Suggested labels

needs-human-review

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	Title clearly and concisely summarizes the main change: implementing detection and handling of non-fast-forward pushes via --force-with-lease in push_with_merge_guard to resolve issue #647.
Linked Issues check	✅ Passed	The PR fully implements the preferred solution from issue #647: detecting branch divergence in push_with_merge_guard and retrying with --force-with-lease when local is both ahead and behind upstream.
Out of Scope Changes check	✅ Passed	All changes are directly scoped to implementing the divergence detection and force-with-lease retry logic specified in issue #647; no extraneous modifications detected.
Docstring Coverage	✅ Passed	Docstring coverage is 100.00% which is sufficient. The required threshold is 80.00%.

_{✏️ Tip: You can configure your own custom pre-merge checks in the settings.}

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch dev-lead/issue-647-20260613-1931

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[gemini-code-assist]

Code Review

This pull request introduces a mechanism to retry a failed push with --force-with-lease when the local branch has diverged from its upstream (e.g., after a rebase), and adds comprehensive unit tests to verify this behavior. The feedback suggests optimizing the parsing of commit counts in _branch_diverged_from_upstream by using Bash's built-in read command instead of invoking awk multiple times.

[don-petry]

Dev-Lead — waiting on PR blockers (intent: review-changes)

PR: #648
No changes were committed, but the PR still has blocking checks or reviews (failing or cancelled checks, or changes-requested reviews). The retry cron will re-attempt automatically. Next attempt after: 2026-06-13T20:07:37Z

[don-petry]

Note

@don-petry I reviewed this PR and no code changes were needed, but it still has blocking checks or reviews (failing or cancelled checks, or changes-requested reviews), so I cannot mark it done yet. I'll re-check automatically.
Next attempt after: 2026-06-13T20:07:37Z

[don-petry]

Dev-Lead — fix-reviews (applied)

Changes committed and pushed.

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[don-petry]

Dev-Lead — review-changes (no-changes)

No changes were needed for this PR.

[don-petry]

Closing as a duplicate of #649, which already implements the --force-with-lease retry for rewritten-history pushes and has merged to main (closing #647). This PR implements the same fix, so it's now redundant. Thanks, dev-lead — the fix is in.

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