Fixed critical bug where fork() completed without errors but branches
were not persisted to storage, causing checkout() to fail with
"Branch does not exist" errors.
Root Cause:
- COW metadata paths (_cow/*) were being branch-scoped incorrectly
- resolveBranchPath() applied branch prefixes to COW paths
- Result: refs written to branches/main/_cow/... instead of _cow/...
- COW metadata (refs, commits, blobs) must be global, not per-branch
Changes:
1. baseStorage.ts (resolveBranchPath):
- Bypass branch scoping for _cow/ paths
- COW metadata now stored globally as designed
- Fixes fork() persistence across all storage adapters
2. brainy.ts (fork):
- Add branch creation verification after copyRef()
- Throw descriptive error if branch wasn't created
- Prevents silent failures in production
3. tests/integration/fork-persistence.test.ts:
- Comprehensive integration tests for fork workflow
- Tests: persist → listBranches → checkout
- Covers Workshop snapshot use case
- Verifies COW metadata is globally accessible
Impact:
- Affects: FileSystem, GCS, R2, S3, Azure storage adapters
- Workshop snapshot restoration now works
- Zero breaking changes, production-scale ready
🤖 Generated with [Claude Code](https://claude.com/claude-code)
Co-Authored-By: Claude <noreply@anthropic.com>
