Navigating (layout/tab switch) tore the xterm view down and called
handle.close(), killing the backend PTY and cutting off running AIs. Now
the view's cleanup only detaches; only an explicit user action kills a PTY.
Backend:
- PortablePtyAdapter: per-session scrollback ring buffer (~100KB, most
recent) + re-subscribable fan-out broadcast replacing the single-take
output_rx. Reader thread feeds both the ring buffer and current
subscribers; on EOF it closes subscribers (streams end) while keeping
scrollback for late re-attach.
- PtyPort: new scrollback() method; subscribe_output is now re-subscribable
(all impls + test fakes updated).
- reattach_terminal IPC command: returns scrollback and re-wires a fresh
output channel on the live session without re-spawning.
- CloseRequested hook kills all live PTYs cleanly on app shutdown.
- TerminalSessions::handles() to enumerate live sessions at shutdown.
Frontend:
- TerminalHandle.detach(); TerminalGateway/AgentGateway.reattach() + mocks.
- TerminalView cleanup detaches (never close); on mount it re-attaches to a
persisted session (repainting scrollback) instead of opening a new PTY.
- LayoutGrid persists the cell's session id via setSession; AgentsPanel
tracks per-agent session ids — both drive reattach-vs-open.
Tests: ring buffer bounds to 100KB keeping newest bytes; scrollback retained;
re-subscription delivers post-reattach output; TerminalView detaches (not
closes) on unmount and reattaches with a known session; mock detach/reattach.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
