Fix useChat so already-rendered user/assistant messages no longer flicker away while an agent turn is actively streaming.
- useChat.ts: during an active streaming turn for the current session, treat stale/empty/cross-session loadMessages responses as append-only against the visible thread instead of replacing it, merging any genuinely new same-session messages in and skipping the session-cache write when the active thread is being preserved.
- ChatView.streaming-thread.test.tsx: add coverage asserting the rendered thread stays visible across mid-turn session-update/tool-call/stale-reload churn.
- useChat.test.ts: add hook-level regression tests for the append-only/merge/cache-skip behavior during active streaming.
- docs/architecture.md, docs/dashboard-guide.md: document the append-only mid-turn thread-stability behavior.
- Add changeset (patch) for @runfusion/fusion describing the user-facing fix.
Files changed:
.../fn-7853-chat-mid-turn-message-stability.md | 7 +
docs/architecture.md | 1 +
docs/dashboard-guide.md | 1 +
.../__tests__/ChatView.streaming-thread.test.tsx | 130 +++++++++++++
.../dashboard/app/hooks/__tests__/useChat.test.ts | 208 +++++++++++++++++++++
packages/dashboard/app/hooks/useChat.ts | 35 +++-
6 files changed, 380 insertions(+), 2 deletions(-)
Fusion-Task-Id: FN-7853
Fusion-Task-Lineage: d9909469-082c-4eeb-81fb-b36d1a9e4705
Co-authored-by: Fusion (runfusion.ai) <noreply@runfusion.ai>
e559b2b538