Files
gitmost/apps/client/src/features/ai-chat/utils/adopt-chat-id.ts
T
agent_coder ba58493909 fix(client): классификация 409-кодов + run-факт плумбинг (#488)
Потребляет реальный контракт #487 на клиенте (без выдумывания кодов):
- error-message.ts: ветки для 409 A_RUN_ALREADY_ACTIVE / SUPERSEDE_TARGET_MISMATCH
  / SUPERSEDE_TIMEOUT / SUPERSEDE_INVALID — человеческие тексты СТРОГО ДО generic-
  веток по статусу (иначе юзер видит сырой JSON {"code":"A_RUN_ALREADY_ACTIVE"});
- extractRunId(message): чтение runId из start-метаданных (зеркало
  extractServerChatId) — live-обновление run-факта для FSM;
- getRun(chatId): POST /ai-chat/run — first-class run-факт с сервера (init на
  маунте + verify после supersede-mismatch).

Плумбинг под FSM-обвязку коммитов 2–5. Тесты: классификатор (все 4 кода + order-
guard), extractRunId.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
2026-07-11 08:02:04 +03:00

85 lines
3.8 KiB
TypeScript

/**
* Pure helpers for adopting a brand-new chat's authoritative server id.
*
* ============================ CANONICAL #137 NOTE ============================
* This docblock is the single authoritative explanation of the new-chat id
* adoption design and the #137 two-tab race it fixes. Other call sites
* (use-chat-session.ts, the server's `chatStreamMetadata`) reference here
* rather than restating it.
*
* When a user sends the first turn of a BRAND-NEW chat, the client has no chat
* id yet (`activeChatId === null`). The server creates the row and the client
* must "adopt" that row's real id so the SECOND turn targets the same chat.
*
* The OLD heuristic adopted `items[0]` — the newest chat in the refetched list.
* That races a second tab: if another tab created a chat in the same moment,
* its row could be `items[0]`, so this tab would adopt the SIBLING chat and
* leak its later turns into it (#137). We adopt by IDENTITY instead, two ways:
*
* PRIMARY path: the server streams the real chat id on the assistant message
* metadata's `start` part (see `chatStreamMetadata` server-side);
* `extractServerChatId` reads it off the finished message and
* `resolveAdoptedChatId` turns it into the id to adopt for a new chat. This is
* authoritative and immune to the race.
*
* FALLBACK path (only when a new chat's first turn errors BEFORE the `start`
* chunk, so no metadata id ever reached the client): adopt the single chat that
* NEWLY appeared in the per-user list relative to a pre-refetch snapshot —
* `newlyAddedChatIds` (the fallback effect adopts only when exactly one id is
* new). This is unambiguous and does not race a second tab the way the old
* "newest chat in the list" guess did.
* ============================================================================
*/
/**
* Resolve the id to adopt from the server-streamed metadata. Returns
* `serverChatId` only for a brand-new chat (`activeChatId === null`) that
* received a truthy id; otherwise null (existing chat, or no id streamed).
*/
export function resolveAdoptedChatId(
activeChatId: string | null,
serverChatId: string | null | undefined,
): string | null {
return activeChatId === null && serverChatId ? serverChatId : null;
}
/**
* Read the authoritative server chat id off a finished assistant message. The
* server attaches it as `message.metadata.chatId` on the `start` part (see
* `chatStreamMetadata`). Returns it only when it is a string; undefined for
* a missing message, missing metadata, or a non-string `chatId`.
*/
export function extractServerChatId(
message: { metadata?: unknown } | undefined,
): string | undefined {
const m = message?.metadata as { chatId?: string } | undefined;
return typeof m?.chatId === "string" ? m.chatId : undefined;
}
/**
* #488: read the authoritative RUN id off a streaming assistant message. The
* server attaches it as `message.metadata.runId` on the `start` part when a run
* wraps the turn (see server `chatStreamMetadata`, #184/#487). This is the live
* run-fact update the client FSM adopts (mirrors `extractServerChatId`). Returns
* it only when it is a string; undefined otherwise.
*/
export function extractRunId(
message: { metadata?: unknown } | undefined,
): string | undefined {
const m = message?.metadata as { runId?: string } | undefined;
return typeof m?.runId === "string" ? m.runId : undefined;
}
/**
* The deduped set of ids present in `afterIds` but not in `beforeIds`. A
* paginated/flatMapped list can repeat the same id, so dedupe: one genuinely-new
* chat must not read as multiple from a duplicate.
*/
export function newlyAddedChatIds(
beforeIds: readonly string[],
afterIds: readonly string[],
): Set<string> {
const before = new Set(beforeIds);
return new Set(afterIds.filter((id) => !before.has(id)));
}