The smart-prefer-main strategy depends on a successful pre-merge rebase
to honor main's deletions. Previously, three failure modes silently fell
through to the -X ours merge, which would re-introduce code main had
just removed (because branch additions vs main deletions don't textually
conflict and -X ours only resolves content conflicts, not modify/delete).
- Hard-fail when prefer-main is paired with worktreeRebaseBeforeMerge=false
(semantically incoherent combination)
- Hard-fail when the pre-merge rebase starts and aborts (any of the three
rebase paths: remote, nested local-base, or fallback local-only)
- Warn (not throw) on environmental silent skips — no remote resolvable
or no worktreePath — so the gap is observable in logs without breaking
common test/setup environments
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
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