Follow-ups on top of kshitijk4poor's cherry-picked salvage of PR #8018:
tools/environments/daytona.py
- PID-suffix /tmp/.hermes_sync.<pid>.tar so concurrent sync_back calls
against the same sandbox don't collide on the remote temp path
- Move sync_back() inside the cleanup lock and after the _sandbox-None
guard, with its own try/except. Previously a no-op cleanup (sandbox
already cleared) still fired sync_back → 3-attempt retry storm against
a nil sandbox (~6s of sleep). Now short-circuits cleanly.
tools/environments/file_sync.py
- Add _SYNC_BACK_MAX_BYTES (2 GiB) defensive cap: refuse to extract a
tar larger than the limit. Protects against runaway sandboxes
producing arbitrary-size archives.
- Add 'nothing previously pushed' guard at the top of sync_back(). If
_pushed_hashes and _synced_files are both empty, the FileSyncManager
was never initialized from the host side — there is nothing coherent
to sync back. Skips the retry/backoff machinery on uninitialized
managers and eliminates test-suite slowdown from pre-existing cleanup
tests that don't mock the sync layer.
tests/tools/test_file_sync_back.py
- Update _make_manager helper to seed a _pushed_hashes entry by default
so sync_back() exercises its real path. A seed_pushed_state=False
opt-out is available for noop-path tests.
- Add TestSyncBackSizeCap with positive and negative coverage of the
new cap.
tests/tools/test_sync_back_backends.py
- Update Daytona bulk download test to assert the PID-suffixed path
pattern instead of the fixed /tmp/.hermes_sync.tar.
Salvage of PR #8018 by @alt-glitch onto current main.
On sandbox teardown, FileSyncManager now downloads the remote .hermes/
directory, diffs against SHA-256 hashes of what was originally pushed,
and applies only changed files back to the host.
Core (tools/environments/file_sync.py):
- sync_back(): orchestrates download -> unpack -> diff -> apply with:
- Retry with exponential backoff (3 attempts, 2s/4s/8s)
- SIGINT trap + defer (prevents partial writes on Ctrl-C)
- fcntl.flock serialization (concurrent gateway sandboxes)
- Last-write-wins conflict resolution with warning
- New remote files pulled back via _infer_host_path prefix matching
Backends:
- SSH: _ssh_bulk_download — tar cf - piped over SSH
- Modal: _modal_bulk_download — exec tar cf - -> proc.stdout.read
- Daytona: _daytona_bulk_download — exec tar cf -> SDK download_file
- All three call sync_back() at the top of cleanup()
Fixes applied during salvage (vs original PR #8018):
| # | Issue | Fix |
|---|-------|-----|
| C1 | import fcntl unconditional — crashes Windows | try/except with fallback; _sync_back_locked skips locking when fcntl=None |
| W1 | assert for runtime guard (stripped by -O) | Replaced with proper if/raise RuntimeError |
| W2 | O(n*m) from _get_files_fn() called per file | Cache mapping once at start of _sync_back_impl, pass to resolve/infer |
| W3 | Dead BulkDownloadFn imports in 3 backends | Removed unused imports |
| W4 | Modal hardcodes root/.hermes, no explanation | Added docstring comment explaining Modal always runs as root |
| S1 | SHA-256 computed for new files where pushed_hash=None | Skip hashing when pushed_hash is None (comparison always False) |
| S2 | Daytona /tmp/.hermes_sync.tar never cleaned up | Added rm -f after download (best-effort) |
Tests: 49 passing (17 new: _infer_host_path edge cases, SIGINT
main/worker thread, Windows fcntl=None fallback, Daytona tar cleanup).
Based on #8018 by @alt-glitch.
