Closes the 4th PR #138 review (3 suggestions, no blockers).
- Double-call safety: a failed turn fires both useChat onFinish AND onError, so
onTurnFinished can run twice in one turn (streamed id, then no id) before a
re-render. onTurnFinished now reads the live id from a ref (set imperatively on
primary adoption) instead of the stale closure, so the 2nd no-id call cannot
re-arm the error-path fallback at the source; the render-phase reconciler is the
second layer. Added a hook test for the sequence — verified it fails only if
BOTH layers are removed (non-tautological).
- Conventions: extracted named UseChatSessionOptions / UseChatSessionResult
interfaces (was an inline param literal + ChatSession); the test derives its
driver props from them.
- Simplification: extracted the chatIdSnapshot(chats) projection used at both the
fallback arm site and the resolver effect.
Architecture notes from the review (caller-driven disarm contract; cross-process
{chatId} type) intentionally left as Variant A per the reviewer's recommendation.
tsc clean; 128 ai-chat tests green.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Closes the 3rd PR #138 review.
Warning fix: the render-phase reconciler only disarms the error-path adoption
fallback when activeChatId actually changes. Pressing 'New chat' while ALREADY
in a new chat keeps activeChatId === null (a no-op atom write), so the reconciler
never fired and a stale armed fallback could adopt the just-failed chat from a
late refetch, yanking the user out of their fresh chat. useChatSession now
returns cancelPendingAdoption(); the window calls it from startNewChat AND
selectChat. (The hook call moved above those callbacks so they can reference it.)
Added a hook test that fails without the explicit disarm, plus a test for the
existing-chat onTurnFinished branch (no adoption + per-chat invalidation).
Cleanups: removed the dead pickNewlyCreatedChatId (the fallback effect uses
newlyAddedChatIds directly with the 0/1/>1 decision inline) and its tests/doc
mention; inlined the two invalidation closures (onTurnFinished is read live by
useChat's onFinish, never in an effect dep array, so memoizing them was needless
ceremony).
Verified: tsc clean, 127 ai-chat tests green; live (z.ai glm-5.2) new chat + 2nd
turn recalled the number in the SAME row (1 chat / 4 messages), no page errors.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Addresses the 2nd PR #138 review (test debt + the Variant-B architecture ask).
The new→persisted chat id lifecycle (mount key, both adoption paths, the
history-load latch, the render-phase reconciler, onTurnFinished) is moved out of
the 768-line window into a new useChatSession hook driven by a pure
threadSessionReducer (reconcile/adopt), so adopt-vs-switch is one explicit
dispatch point and the scattering the review flagged is gone (window: 768→~620).
Tests (the blockers):
- use-chat-session.test.tsx — hook-level locks incl. the #137 regression
(adopts the authoritative streamed id 'A', NOT chats.items[0]='B' — fails on
the old heuristic), the error-path fallback (arm/adopt/ambiguous/add+delete),
the disarm-on-reconcile lock (a fallback armed then switched away must not be
adopted by a late refetch), in-place-adopt-keeps-key vs external-switch-remount,
and the waitingForHistory latch.
- extractServerChatId (reading message.metadata.chatId) and newlyAddedChatIds
extracted as pure helpers with unit tests; threadSessionReducer tested.
Cleanups: single canonical #137 explanation in adopt-chat-id.ts (other sites
reference it); fallback effect computes the set diff once; invalidate callbacks
memoized; redundant invariant tests folded.
Behavior preserved — re-verified live (z.ai glm-5.2): new-chat adopt + 2nd turn
in the same row, no mid-conversation remount, two-tab race leak-free, switch to
an existing chat reseeds full history, reload restores history.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Addresses the PR #138 review's architecture note (the deferred 'non-blocking'
item). The brand-new -> persisted chat identity was spread across two separate
useState slots (threadKey + liveThreadChatId) plus a render-phase guard, so the
mount key and the live thread's chat id could in principle diverge.
Consolidate them into ONE atomic state object { key, chatId } with pure,
unit-tested transitions in thread-identity.ts:
- newThread(newKey) — a brand-new id-less chat (fresh session key);
- switchThread(chatId) — switch to an existing chat (key := chat id) -> remount;
- adoptThread(prev, id) — a new chat learns its real id IN PLACE (key unchanged
-> no remount, live useChat store preserved).
The 'key vs chatId diverged' state is now unrepresentable. The render-phase
reconciliation stays (the atom is also set externally, e.g. page-history's
history-item opening a referenced chat), but adoption vs switch is now explicit.
Behavior is unchanged; verified live: new-chat adopt + 2nd turn in the same row,
no mid-conversation remount, the two-tab race stays leak-free, switch-to-existing
remounts + reseeds, and reload restores full history. Adds thread-identity.test.ts.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Addresses the PR #138 review.
Blocker 1 — duplicate chat row: a brand-new chat whose first turn errors BEFORE
the SSE 'start' chunk never receives the authoritative chatId, so metadata
adoption can't run; a retry then sent chatId:null and the server inserted a
SECOND chat row, orphaning the first turn. Keep metadata adoption as the primary
path (resolveAdoptedChatId) and add a bounded, unambiguous fallback: on a
new-chat finish with no server id, snapshot the known chat ids and, once the
list refetch lands, adopt the SINGLE newly-appeared id (pickNewlyCreatedChatId).
Zero or >1 new ids (e.g. two tabs racing) → no adoption — no items[0] guessing,
so #137 stays fixed. The wait-for-refetch guard compares set membership (robust
to a concurrent delete), and the diff dedupes so a repeated id from a paginated
list never reads as ambiguous.
Blocker 2 — tests: new adopt-chat-id.test.ts covers both pure helpers (adopt
decision + newly-created-id diff incl. dedupe/reorder); the server
messageMetadata callback is extracted to chatStreamStartMetadata and unit-tested
(start -> {chatId}, otherwise undefined).
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Migrations auto-run on boot only in production (the built image / start:prod);
the local dev stand (pnpm dev / nest start --watch) does NOT auto-run them, so
after pulling or switching branches you must apply them with
'pnpm --filter server migration:latest' or endpoints touching new columns 500
(e.g. a freshly-added ai_chats.page_id blanket-500s all of AI chat).
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
A brand-new chat (activeChatId === null) had no way to learn the id of the row
the server created: the SSE stream never returned it, so the client adopted the
NEWEST chat in the per-user list (chats.items[0]). With two tabs open, a second
tab creating a chat at ~the same time made its row the newest, so the first tab
adopted the wrong id — its later turns persisted into the other chat and the
agent rebuilt history from it (commands leaked between chats), while the live UI
still showed the original conversation. (#137)
The server now attaches the authoritative chatId to the streamed assistant
message via the AI SDK messageMetadata on the 'start' part, so it reaches the
client on the first chunk. The client reads message.metadata.chatId in useChat's
onFinish and adopts that id in place (no remount, so the live turn and the
thread's chatIdRef follow the real id and the next turn targets the right chat).
The chats.items[0] guess and the adoptNewChat ref are removed.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
