TestCarstoreConcurrentWritesTwoOpeners failed in CI on 2026-09-13 with
"database is locked" while the code was correct. It hammered the file with
five concurrent writers and asserted that no lock error surfaced within the
5 s busy_timeout, which on a loaded runner with every package testing in
parallel is a statement about the disk, not the code. The property it guards
(busy_timeout applied to every connection of every pool on a hold database,
c44a874) is now tested directly: one connection holds the write lock via
BEGIN IMMEDIATE, a second writer is shown to block rather than fail, and to
succeed once the lock is released. Both topologies are covered (the shared
OpenHoldDB pool, and a second opener on the same file, in both directions),
and a control shows a pool without busy_timeout fails immediately under the
same lock, so the passing tests are known to observe the mechanism.
The failure was also buried under the INFO lines every hold and PDS test
emits while booting. internal/testlog.Quiet swaps the default slog handler
for a discard handler unless the run is verbose or ATCR_TEST_LOGS is set,
and every package that produced that output now calls it from TestMain.
`go test` only shows a package's output when it fails, so this changes
nothing for passing runs and leaves a failing one readable.
Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Hho5da4daoCoPBJ9tCrL7s
Evan JarrettandClaude Fable 5.1