Excluding pre-restore-* from db_dumps made that list stable across restores, so
CaptureRecoveryUnit's already-current early return began firing where it never
had - and the prune, which sat after it, stopped running in exactly the case it
exists for. Measured on demo-hp minutes after the change: four undo copies on
disk against a cap of three.
The prune is housekeeping on the dump directory and is independent of whether
the manifest needs rewriting, so it belongs above the check. Pruning cannot
disturb dbDumps, which no longer contains those names.
Pinned by TestR361_UndoCapHoldsWhenTheUnitIsAlreadyCurrent; its red-proof moves
the call back below the return and the cap fails at 5.
writeSafetyDump called DumpOne into the app's OWN unit dir and renamed the result
to pre-restore-* afterwards. DumpOne writes <stack>-<dbtype>.sql - the app's
canonical dump - so every safety dump overwrote the app's real backup and then
moved it away, leaving the app with no database backup until the next nightly
run. A local restore-from-unit in that window tells the customer the app never
had a database.
The comment beside it asserted the rename meant it 'can never overwrite the app's
real dump'. False as written, and believed for four months. Measured live before
the fix: docmost and bookstack each held only pre-restore-* files and no
canonical dump.
DumpOneTo takes the final path and derives its own .tmp from it. DumpOne keeps
its signature and calls it with the canonical name. writeSafetyDump asks for its
own name directly; the rename is gone; the comment now states the invariant and
how it is enforced.
db_dumps no longer lists the undo copies. All three consumers of Manifest.DBDumps
were grepped and named - all inside recovery_unit.go, none reads it for recovery.
The files are neither deleted nor hidden.
Tests 1485 -> 1493. FIVE red-proofs, TWO PASSED first time and both are reported:
the behavioural tests inject the dump seam so a mutation inside DumpOneTo was
invisible, and 1.3 had no test at all. Guards added at the layer each defect
lives in; both mutations then convicted.
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