The reworked bundle's PORT.md makes row-level last-write-wins conditional
on three gates, each learned by losing real data. The port's sync broke
all three, and had four more ways to lose or stall work. Both ends change,
so this is one protocol version, refused by the other side if mismatched.
Gate 1, hydration. A device now pulls every page the server holds before
it may push anything; it used to push first. The 14 Sep laptop — a
week-old copy re-stamped at boot and pushed over a week of phone work —
is now a test, and the phone's week survives it. Boot writes nothing
syncable either: the lesson opens with the app's own words (the artifact's
seeded turn) and waits for Start, instead of stamping a reply and a
progress edit before a server can even be configured.
Gate 2, a counter. Every row remembers the change_seq it last agreed with
(base_seq). The server applies a write only if that still matches —
compare-and-swap under an advisory lock — and otherwise returns its copy
as a conflict. No clock is compared anywhere: a device an hour fast used
to win every conflict for an hour, and a slow one's newer edit was
silently dropped with HTTP 200. dirty and rev replace the timestamp
watermark, which lost edits whenever a clock moved backwards.
Gate 3, no silent shrinking. A conflict is settled by what each copy
holds (sync/resolve.ts): more reviews, more evidence, a finished unit, the
further roadmap position, the union of learned grammar. A deliberate
shrink is explicit: a reset or a cleared lesson raises a marker every
device obeys, including its own unsynced edits, so a reset is not undone
by a device that had not heard of it. Trimming the transcript is local
and tombstones nothing — it used to delete the other device's turns.
Also fixed on the way:
· keys travel as JSON arrays — a space in 몇 명 used to stop every
device's pull at that row, permanently;
· pulls take a shared lock against pushes, so a change_seq committed
out of order can no longer be skipped;
· study_log and peek are per device and summed, so two devices' reviews
of one day both count;
· each user's data has an epoch; a server that lost it is detected,
and the device re-hydrates and offers its data back;
· a protocol-1 client is refused with 426 rather than half-understood.
Migration 9 adds the columns, re-keys the counters and tombstones; the
server drops protocol-1 rows once (none were deployed). Verified: 14
two-device scenarios against a real Postgres, and two browser profiles
syncing a lesson through the UI.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Cards point at lemmas by id, and an id was the entry's position in the
sorted build. One word added near the top of the dictionary would have
moved every card below it onto a different word — silently, because loaded
bands were recorded by number and a rebuilt dictionary never reached an
existing install anyway. A custom word took max(id)+1 on whichever device
added it, so the same id meant different words on a phone and a laptop.
An id is now lemmaId(headword, pos), a 53-bit hash defined once in
shared/ and used by the build, the loader, custom words and the migration.
The build asserts all 30,520 entries are collision-free, and a test pins the
function itself, since changing it re-keys every card.
Band files are format 2: they carry no ids at all. The loader derives each
id from the word, and a surface names its lemma by row index in the same
file. Writing hashed ids out cost 0.5 MB of incompressible digits; leaving
them out makes the files smaller than before (1.1 MB -> 1.0 MB).
The loaded dictionary is now versioned by its band hashes, so a rebuild
reloads on the next boot — safe only now that a reload cannot move a card.
Migration 6 re-keys an existing install without stamping anything: cards
and their tombstones move through the lemma rows still loaded, custom words
become custom_word rows (the learner's data, which can travel) carrying the
time their card was made, and the dictionary is dropped to reload.
Sync is paused until the protocol that replaces it lands: the server still
holds rows under the old ids, and exchanging them would plant cards that
name no word.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
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>
