569 2026 01 27 17 52 14 Insert Before Stream Fix F3d11f8a

Pre-Flight Checks

• DoR satisfied? Yes - plan is complete with acceptance tests
• Access/secrets present? N/A - no secrets needed
• Fixtures/data ready? N/A

Note: Plan references ChatContainer which doesn't exist. User approved creating minimal ChatContainer first.

Execution Progress

Task 0: Create Minimal ChatContainer Widget

Status: COMPLETED

Created src/tunacode/ui/widgets/chat.py with:

• ChatContainer class extending VerticalScroll
• _current_stream tracking for active streaming widget
• _insertion_anchor tracking for post-stream insertion point
• write() method for backward compat with RichLog
• start_stream(), update_stream(), end_stream(), cancel_stream() lifecycle methods
• insert_before_stream() for positioning tool panels correctly

Files created:

• src/tunacode/ui/widgets/chat.py

Files modified:

• src/tunacode/ui/widgets/__init__.py - added ChatContainer export

Task 1: Add insertion anchor tracking to ChatContainer

Status: COMPLETED

Implemented in ChatContainer:

• _insertion_anchor: Widget | None attribute
• end_stream() captures finalized stream widget as anchor
• cancel_stream() captures previous sibling as anchor

Task 2: Update insert_before_stream() to use insertion anchor

Status: COMPLETED

insert_before_stream() now handles three cases:

1. Active stream: insert before _current_stream
2. Stream ended: insert before _insertion_anchor (finalized message)
3. No context: append to end

Task 3: Clear insertion anchor on new request

Status: COMPLETED

start_stream() clears _insertion_anchor = None to prevent stale positioning. clear() also clears the anchor.

Task 4: Handle cancel scenario insertion anchor

Status: COMPLETED

cancel_stream() finds the widget that was BEFORE the stream widget and sets it as anchor. This allows late-arriving tool panels to insert at the correct position after cancel.

Task 5: Wire into app.py

Status: COMPLETED

Changes to src/tunacode/ui/app.py:

• Replaced RichLog import with ChatContainer
• Added ChatContainer to widget imports
• Changed self.rich_log: RichLog to self.chat_container: ChatContainer
• Added rich_log property alias for backward compatibility
• Updated compose() to create ChatContainer instead of RichLog
• Added chat_container.start_stream() at request start
• Added chat_container.end_stream() in finally block before writing response
• Added chat_container.cancel_stream() in action_cancel_stream()
• Changed on_tool_result_display() to use insert_before_stream()

Files modified:

• src/tunacode/ui/app.py
• src/tunacode/ui/welcome.py - Updated type hint to use WriteableLog protocol

Gate Results

• Tests: PASS (512 passed)
• Type checks: PASS (no new errors introduced)
• Linters: PASS (all checks passed)

Files Changed Summary

Notes

• Branch: fix/insert-before-stream-race
• Rollback point: 5efc5423
• End commit: 9be710d9
• The rich_log property alias ensures backward compatibility for code that references app.rich_log

Execution Report

Date: 2026-01-27 Plan Source: memory-bank/plan/reserch.md Start commit: 5efc5423 End commit: 9be710d9 Branch: fix/insert-before-stream-race Final status: SUCCESS

Outcomes

• Tasks attempted: 6 (0 + 5 from plan)
• Tasks completed: 6
• Rollbacks: None
• All gates passed