Row-level last-write-wins on updated_at, cursor-based on a server-assigned
change_seq. The schema was built for this in step 1, so the work here is
the three things it did not yet have.
Tombstones (migration 4). Row-level sync cannot express a delete: with the
row gone there is nothing to compare timestamps against, so the other
device pushes its still-live copy back and the row silently returns. Every
delete path now writes a tombstone inside the same transaction.
The wire format lives in shared/sync-protocol.mjs and is imported by both
sides, so there is one definition rather than two that drift. It carries
the syncable-meta allowlist, which is the load-bearing part: meta mixes the
learner's preferences with bookkeeping that describes one install, and
replicating dict.loadedBands would tell a phone that had loaded bands 0-2
it holds every row the desktop has — the word rail would then fail to find
words it believes are present.
The sync loop pushes first, then pages the pull. Two details it would be
easy to get wrong, both commented at their site:
- The pull cursor advances only as rows are applied, never from the push
response. The server's newest change_seq includes rows this device has
not seen; adopting it skips them permanently, and nothing ever asks for
that range again.
- Pulled rows advance sync.pushedAt too, bounded by the instant the sync
started. Otherwise they look like local edits and get pushed straight
back, and an edit made during the sync is not swept up with them.
Seeded rows carry updated_at = 0, so a fresh device is never dirty and can
never win a conflict — the artifact's clobbering bug stays unrepresentable.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Closes REVIEW.md §2. 167 of 371 roadmap words had no lexicon entry, so the
word rail silently showed nothing. Now:
Roadmap words: 371/371 resolve
Spiral targets: 35/35 resolve
Deck words: 386/386 resolve
and npm run dict:assert makes it a blocking build failure, not a silent
empty rail.
No runtime morphological analyser ships. lib/conjugation.js surfaceForms()
runs at BUILD time over every verb and adjective, so looking up a conjugated
form is an index hit on the surface table.
The frequency join had to be inverted. A subtitle frequency list holds
surface forms; a dictionary holds lemmas whose -다 citation form barely
occurs in running text, so joining on headword gives verbs a frequency of
roughly zero. Expanding each lemma into the forms it plausibly takes and
summing recovers 하다 from 118 to 89,041. Forms claimed by more than one
lemma are dropped rather than split, so homographs don't inherit each
other's mass. Those expansions score frequency only — the surface table
itself stays strictly surfaceForms() output plus the headword.
Bands are one per curriculum phase. Phase 1 admits no frequency band at
all: during the writing-system phase every word must be phonologically
legal for the unit reached, and a rank ceiling would hand the learner a
겹받침 during unit 1.4. shared/phonology.mjs lifts validate.mjs's own
feature ladder to enforce that; it agrees with the validator on all 371
words.
Sources are chosen automatically — KRDICT when vendored, otherwise the
kaikki.org extract. KRDICT's download is a JS form behind anti-bot
protection, so it cannot be fetched by CI; the derived band files are
committed instead, which the app needs offline regardless. Attribution and
the share-alike terms are in NOTICE.md.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
