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[Bug] Web UI: Duplicate text rendering during streaming due to dual render path race condition in session-turn.tsx #14280
Description
Description:
What's happening
Noticed something weird in the web UI - sometimes when the AI is streaming a response, the text shows up twice. Like, you'll see the full response finish streaming, then bam - duplicate paragraphs appear out of nowhere. Been seeing this more often after tool calls finish.
Setup
- opencode serve --print-logs --log-level=INFO
- OpenCode v1.2.6
- Web interface on Windows 11, Chrome
- Happens randomly but seems worse with longer responses
How to reproduce
- Just use the web UI normally
- Ask something that gets a decent-length reply (I usually ask for code examples)
- Watch carefully as it streams in
- Sometimes right at the end, you'll see text doubled up
What I think is going on
Been digging through session-turn.tsx and pretty sure I found the culprit. There are two places rendering the same assistant message content:
- The streaming view (
AssistantMessageItem) - shows chunks as they arrive - The "done" view (that summary section at the bottom) - shows final formatted result
The problem is they can both render at the same time because of how the filtering works. Here's the busted logic:
// This comparison is flaky during state transitions
if (responsePartId && responsePartId === lastTextPart()?.id) {
parts = parts.filter((part) => part?.id !== responsePartId)
}When working flips from true to false, Solid's reactivity doesn't sync these two paths properly. The summary section renders the full text, but the streaming section hasn't filtered out its last chunk yet. Result: double vision.
Also noticed the CLI has a similar mess with lastPartText getting wiped in handleToolPart, causing the same replay bug there.
Activity
github-actions commentedon Feb 19, 2026
This issue doesn't fully meet our contributing guidelines.
What needs to be fixed:
Please edit this issue to address the above within 2 hours, or it will be automatically closed.
This issue might be a duplicate of existing issues. Please check:
session-turn.tsx, the samehideResponsePartfiltering bug, and proposes the same fix. If the fix from Text Duplication in Chat Response UI #13658 didn't fully resolve the problem, please reference that issue and explain what's still occurring rather than opening a new report.If you believe this was flagged incorrectly, please let a maintainer know.
github-actions commentedon Feb 19, 2026
Thanks for updating the issue! It now meets our contributing guidelines. We appreciate you taking the time to revise it.
github-actions commentedon Apr 21, 2026
To stay organized issues are automatically closed after 60 days of no activity. If the issue is still relevant please open a new one.