Task 6 of the LocalDb Phase 1 adoption plan. Copies site-tracking.db and
site_events.db into the consolidated database, then renames each source to
<name>.migrated.
Runs AFTER RegisterReplicated, deliberately: capture is trigger-based, so rows
inserted before registration would never enter the oplog and would never reach
the peer - silently. There is a test asserting migrated rows land in
__localdb_oplog, because every other test in the file would still pass with that
ordering reversed.
Idempotent twice over. Tracking rows keep their existing TEXT primary key, so
INSERT OR IGNORE dedupes naturally. Legacy events had autoincrement integer ids,
which the consolidated schema replaced with GUIDs; they get DETERMINISTIC ids of
the form mig-{NodeName}-{legacyId} rather than fresh GUIDs, so a migration that
crashes between commit and rename cannot duplicate history on the next boot. The
NodeName prefix keeps the two nodes of a pair from colliding on their independent
legacy id sequences. Both properties are covered, including an explicit
crash-window test that undoes the rename and re-runs.
All-or-nothing: the copy commits in one transaction and the rename happens only
afterwards, so a failure throws out of OnReady, fails host startup, and leaves
the legacy files untouched. Deviation from the plan: it specified
BeginTransactionAsync, but OnReady is a synchronous Action<ILocalDb>. A raw
transaction on a CreateConnection() connection gives identical atomicity and
identical trigger capture without blocking on async in a startup callback.
Legacy paths come from the OLD config keys and fall back to the CWD-relative code
defaults, because that is where the old code actually wrote them. Note this means
both legacy databases have always lived outside the mounted data volume and were
already discarded on every container recreate - so on the rig this migrator will
usually find nothing, which is a legitimate no-op rather than a failure. Phase 1
incidentally fixes that data-loss bug.
Non-failure cases are covered too: missing files, a legacy file with no such
table, and in-memory legacy connection strings from test/dev configs.
Verified: build 0 warnings; Host 316/316 (9 migrator tests new).
Claude-Session: https://claude.ai/code/session_01BL2Vu1ESDQ9SCN4gVKkdts
Joseph Doherty