2 Commits

Author	SHA1	Message	Date
Garry Tan	b315ccb0d4	feat(terminal-agent): scrollback ring buffer + detach state machine + re-attach ... The agent side of Commit 3 — the "magic" feature. A network blip (wifi hiccup, MV3 panel suspend, brief Chromium pause) now silently reconnects the sidebar to the SAME claude session with scrollback intact. No more "Session ended" message + manual Restart click + losing your tool-call output. Server-side /pty-session/reattach (25ef24e9) and the extension re-attach loop (next commit) close the loop end-to-end. Ring buffer (T10): * Per-session frames: Buffer[] capped at 1 MB (env-overridable via GSTACK_PTY_RING_BUFFER_BYTES). Each PTY write is one frame, so eviction is at frame boundaries and never cuts a UTF-8 sequence or ANSI CSI in half. * appendToRingBuffer eviction loop keeps at least one frame even at extreme caps — a single oversized frame can't empty the buffer. * Alt-screen tracking via canonical xterm CSI ?1049h / CSI ?1049l sequences. lastIndexOf comparison so trailing state wins when both appear in one render frame (quick tool-call open+close). Replay payload (T5 — codex outside-voice): * buildReplayPayload prefixes DECSTR soft reset (\x1b[!p) and conditionally re-enters alt-screen if claude was in a tool call at detach. The client writes RIS (\x1bc) FIRST to clear pre-blip xterm content; the server's prelude resets character attributes; the ring buffer replays cleanly on top. * Order is enforced by the {type:"reattach-begin"} text frame the agent sends right before the binary replay — client waits for it, writes RIS, then treats the next binary frame as the replay payload. Detach state machine (T9): * PtySession.liveWs decouples the PTY callback from the original ws closure. On re-attach, swapping session.liveWs is enough — the on-data callback writes to the new ws automatically. * close(ws, code, _reason): codes 4001 (intentional restart), 4404 (no-claude), and 1000 (clean exit) trigger immediate dispose. Anything else (1006 abnormal, 1001 going-away from network blip / panel suspend) starts a 60s detach timer instead. claude keeps running, output keeps accumulating in the ring buffer. * Detach timer is unref'd so the bun process can still exit cleanly on natural shutdown. * Sessions without a sessionId (legacy single-shot grants) can't re-attach by definition — those fall through to immediate dispose. Re-attach lookup (T9): * WS open() checks sessionsById[sessionId] FIRST. If a detached session is sitting there, cancel its detach timer, swap liveWs, rebind the WS-keyed map, restart keepalive, send reattach-begin + replay payload. The PTY process is unchanged. * /internal/restart now cancels any pending detach timer before disposal — otherwise the timer would later try to dispose an already-disposed session. Env knobs for e2e: * GSTACK_PTY_RING_BUFFER_BYTES — compress to 256 for eviction tests. * GSTACK_PTY_DETACH_WINDOW_MS — compress to 1000 for "did the timer fire?" tests without waiting a minute per assertion. Tests: * browse/test/terminal-agent-detach-reattach.test.ts — 10 static-grep tripwires for the load-bearing properties: interface shape, env knobs, eviction floor, alt-screen tracking, replay prelude composition, re-attach lookup, close-code routing, detach timer unref, /internal/restart timer cancellation, on-data through session.liveWs. * browse/test/terminal-agent-session-routing.test.ts test 7 widened to match the new close(ws, code, _reason) signature. * browse/test/terminal-agent-keepalive.test.ts test 3 widened similarly. Both stay regressions for the prior contract. Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>	2026-05-23 23:21:22 -07:00
Garry Tan	d8751e91df	feat(terminal-agent): 25s WS keepalive ping/pong + client keepalive frames ... PTY connections were dying silently after NAT idle timeouts (30-60s on most home routers, even shorter on some carrier-grade NAT) and Chrome MV3 panel suspension. Neither side noticed until the user's next keystroke produced no output. Both sides now drive a 25s keepalive cycle. Server side (browse/src/terminal-agent.ts): * New ws.open handler constructs the PtySession eagerly and starts a setInterval that sends `{type:"ping",ts:Date.now()}` every 25s. Interval handle stored on session.pingInterval so close() can clear it. * PtySession.pingInterval field added; cleared in ws.close before disposeSession runs. Prevents timer leak across reconnects. * Message handler accepts `{type:"ping"|"pong"|"keepalive"}` silently — keepalive frames are a liveness signal at the TCP layer, no state to update. Existing resize/tabSwitch/tabState handling unchanged. * GSTACK_PTY_KEEPALIVE_INTERVAL_MS env knob (default 25000) lets the upcoming e2e tests compress idle assertions without 30s waits. Client side (extension/sidepanel-terminal.js): * Belt-and-suspenders: client also runs a 25s setInterval that sends `{type:"keepalive"}`. Defends against Chrome pausing our timers if the server-side ping ever gets dropped (rare but possible in MV3). * Ping reply: on `{type:"ping",ts}` from the server, immediately send `{type:"pong",ts}`. Lets the agent observe round-trip latency for free and confirms the channel is bidirectional. * Interval cleared in three teardown paths: ws.close handler, teardown(), forceRestart(). Three paths exist because the sidebar can exit the LIVE state through any of them; all three must clean up or we leak timers across reconnects. Test (browse/test/terminal-agent-keepalive.test.ts): * Static-grep tripwires for the 7-point protocol contract: agent has a configurable interval, open() starts the ping, close() clears it, message handler accepts keepalive vocabulary, client sends keepalive + replies pong, and all three client teardown paths clear the timer. * Wire-level tests (actually observe a ping after 25s) belong in the e2e tier — adding them here would either flake on slow CI or require a real Bun.serve listener per test which we don't want to pay for in the free tier. Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>	2026-05-23 23:09:23 -07:00