fix(app): prevent streaming content duplication during event coalescing#14820
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praxstack wants to merge 2 commits intoanomalyco:devfrom
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fix(app): prevent streaming content duplication during event coalescing#14820praxstack wants to merge 2 commits intoanomalyco:devfrom
praxstack wants to merge 2 commits intoanomalyco:devfrom
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…cing When message.part.updated events coalesce within a 16ms batch window (text-end replaces text-start at the same queue index), stale message.part.delta events remained in the queue. On flush, the reducer applied the full text from the coalesced update, then appended the stale deltas on top — doubling the content. Fix: When a message.part.updated event coalesces over an earlier entry, void all stale message.part.delta events for the same messageID:partID already in the queue. Voided indices are skipped during flush. Zero overhead in normal operation (voided set stays empty when no coalescing occurs). Scoped by messageID+partID to avoid affecting unrelated parts. Fixes content repetition visible during LLM streaming in desktop UI. Content displays correctly after app restart (loaded from DB).
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Issue for this PR
Closes #14822
Type of change
What does this PR do?
During streaming, SSE events are batched in 16ms windows.
message.part.updatedevents coalesce (text-end replaces text-start at same queue index), butmessage.part.deltaevents never coalesce. When both land in the same batch, the full text gets applied via reconcile, then stale deltas append on top — doubling the content.The fix adds a
voidedSet in global-sdk.tsx. When amessage.part.updatedcoalesces, all stalemessage.part.deltaevents for that messageID+partID are voided. Voided indices are skipped during flush. Zero overhead when no coalescing occurs (the common case).How did you verify your code works?
bun run --cwd packages/desktop tauri devScreenshots / recordings
Text-only change in event batching layer, no UI changes.
Checklist