perf: memoize transcript pipeline + fix streaming lockups - #15
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Expo SDK 54+ removed --non-interactive. Scripts failed when run from a TTY. Set CI=1 in spawnSync env to force non-interactive mode.
Wave 1 (chat-cards, chat-content): - TranscriptMessage wrapped in React.memo with areEqual comparator keyed on entry ref + copied/speaking/canSpeak. Non-streaming cells skip re-render during token deltas. - maintainVisibleContentPosition extracted to module constant. - extraData wrapped in useMemo. - TranscriptSkeleton placeholder (3 pulsing bubbles, native driver) wired into FlashList ListEmptyComponent during initial load. Wave 2 (format, selectors, provider): - toTranscriptEntry: WeakMap cache keyed on record ref. Skips heavy if/else chain for unchanged records. - getSessionPreviewById: WeakMap cache keyed on messages array ref. Skips per-session getHistoryPreview recompute. - refreshMessages: merge new fetch with previous by record id. Preserves record refs AND array ref when content unchanged. Equality covers BOTH parts and info (catches post-hoc info.error additions during streaming-failure scenarios). - MarkdownText: tokenizer wrapped in useMemo + memo wrap. Net effect: during a token delta, only the one streaming cell re-renders. Previously every parent state change re-rendered all visible cells.
- Collapse leading '&&' operator to trailing style (0 other instances of leading '&&' chains in the repo; rest of file uses single-line or trailing operator). - Drop 'Wave 1' / 'Wave 2.2' plan nomenclature from comments — internal planning artifact absent from repo docs. Replaced with descriptive references to the actual optimizations. - Remove stray double blank line between TranscriptSkeleton memo and ChatContentProps type declaration. - Document the new cross-layer invariant in docs/state-and-data.md Important Data Invariants section: SessionMessageRecord objects in messagesBySession are never mutated in place. The WeakMap caches in format.ts and opencode-provider-selectors.ts depend on this contract; refreshMessages preserves refs when content is unchanged.
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Problem
The transcript list re-renders every visible cell on every parent state change during streaming. Token deltas from SSE cause
isRefreshingMessagestoggles,pendingInteractionscount updates,runningflips — each one re-renders all visibleTranscriptMessagerows even though only the streaming row changed. Result: UI lockups during assistant replies, especially on lower-end devices.Fix
Memoize the transcript pipeline end-to-end so non-streaming cells skip re-render during token deltas.
Wave 1 — cell-level memoization
components/chat/chat-cards.tsx: wrapTranscriptMessageexport inReact.memowithareEqualcomparator keyed on entry ref +copied/speaking/canSpeak. Callback identity intentionally excluded — they only fire on user action.components/chat/chat-content.tsx: extractmaintainVisibleContentPositionto a module-levelas const; memoizeextraDataviauseMemo([copiedMessageId, speakingMessageId]). AddTranscriptSkeletonplaceholder (3 pulsing bubbles, native-driver opacity loop) wired into FlashListListEmptyComponentduring initial load.Wave 2 — pipeline memoization
lib/opencode/format.ts:WeakMap<record, entry>cache intoTranscriptEntry. Skips heavy if/else tokenization chain for unchanged records.providers/opencode-provider-selectors.ts:WeakMapcache ingetSessionPreviewByIdkeyed on messages array ref.providers/opencode-provider.tsx:refreshMessagesmerges new fetch with previous by record id, preserving record refs AND array ref when content unchanged. Equality covers BOTH parts and info (catches post-hocinfo.erroradditions during streaming-failure scenarios).components/chat/chat-markdown.tsx: tokenizer wrapped inuseMemo+memowrap.Style pass
&&operator chain to trailing style (matches rest of codebase).chat-content.tsx.SessionMessageRecordimmutability invariant indocs/state-and-data.md§ Important Data Invariants.Build script fix
scripts/build-android-development.mjs+scripts/build-android-release.mjs: replaced deprecated--non-interactiveflag withCI=1env var. Expo SDK 54+ removed the flag; scripts failed when run from a TTY.Files changed
components/chat/chat-cards.tsxcomponents/chat/chat-content.tsxcomponents/chat/chat-markdown.tsxcomponents/chat/chat-view-styles.tslib/opencode/format.tsproviders/opencode-provider.tsxproviders/opencode-provider-selectors.tsscripts/build-android-development.mjsscripts/build-android-release.mjsdocs/state-and-data.mdValidation
npm run typecheck✓npm run lint✓npm run test:format✓npm run test:usage✓npm run test:fake-server:self✓Net effect
During a streaming token delta, only the one streaming cell re-renders. Previously every parent state change re-rendered all visible cells. During initial session load, a
TranscriptSkeletonplaceholder shows pulsing bubbles instead of a blank snap-to-populated.