hermes backup freezes mid-archive when a .db file under HERMES_HOME is
locked by another process — e.g. a live Chromium profile database held
with an exclusive lock by a running browser. sqlite3.Connection.backup()
retries SQLITE_BUSY indefinitely and never honors the connection's busy
timeout, while a plain statement on the same source fails cleanly after
~5s with "database is locked".
Fixes:
- Probe the source with a cheap read before snapshotting, so a locked
database fails fast instead of hanging the whole backup.
- Add a watchdog that interrupts the source connection after 15 minutes
as a last resort for pathological cases.
- Exclude browser-profiles/ from full backups: the CDP browser profile is
live, regenerable (cache + re-login), and unsafe to snapshot while
running. On a real install this cut the backup from 28,396 files /
1.1 GB to ~4,000 files / 548 MB, completing in ~33s instead of hanging.
The pre-update automatic backup shares this code path and was equally
at risk.
Adds a regression test that holds an EXCLUSIVE transaction in a separate
process and asserts _safe_copy_db returns False in bounded time.
xthezealot
d422f7103e