fix(wta): log process teardown + agent-pane disconnect; trim log spam#298
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vanzue wants to merge 10 commits into
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fix(wta): log process teardown + agent-pane disconnect; trim log spam#298vanzue wants to merge 10 commits into
vanzue wants to merge 10 commits into
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Helper/master deaths were undiagnosable: on a non-graceful teardown the process vanished mid-stream and the non-blocking appender's buffered tail was lost (shutdown_flush never ran), while the C++ pane side stayed silent. The success path was logged exhaustively; the teardown path was not. - logging: install a SetConsoleCtrlHandler that logs which control event (CTRL_CLOSE/LOGOFF/SHUTDOWN/BREAK) tore the process down and drains the appender so final records (incl. the transport-lost WARN) reach disk. Returns FALSE -- termination behavior unchanged. Wired into main() so it covers both helper and master. (A hard taskkill /F sends no control event and stays untraceable by design.) - Tab.cpp: _agentPaneLog when the agent pane's connection closes, so a dead helper is recorded on the C++ side and correlates to the millisecond with the Rust logs -- fires even when the master is gone and cannot emit restart_agent_pane. - trim per-token-chunk / per-VT-sequence logs (master forwarding x2, acp session_notification, autofix WtEvent/classified/cross-tab-drop) from debug to trace; keep one per-event breadcrumb at debug and all connection/lifecycle logs intact. cargo +stable check passes. Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
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Pull request overview
This PR improves diagnosability of Windows Terminal Agent (WTA) failures by ensuring teardown paths emit logs and by reducing high-volume success-path debug logging that can drown out lifecycle signals. It also adds a C++-side log record when the agent pane’s backend disconnects to correlate UI-side behavior with Rust-side logs.
Changes:
- Add a Windows console control handler in WTA to log teardown signals and flush buffered logs before termination.
- Log agent-pane backend disconnects from the TerminalApp
Tabto make UI-side disconnects visible. - Reduce log volume by demoting per-chunk/per-sequence debug logs to trace across ACP and autofix paths.
Reviewed changes
Copilot reviewed 7 out of 7 changed files in this pull request and generated 2 comments.
Show a summary per file
| File | Description |
|---|---|
| tools/wta/src/protocol/acp/client.rs | Demotes per-streamed-chunk ACP session_notification logging to trace to reduce debug noise. |
| tools/wta/src/master/mod.rs | Demotes per-chunk session notification routing logs to trace to reduce master log volume. |
| tools/wta/src/main.rs | Installs the new teardown control handler immediately after logging init. |
| tools/wta/src/logging.rs | Adds install_ctrl_handler() to log/flush on console teardown control events. |
| tools/wta/src/app.rs | Demotes high-volume autofix event/classification logs to trace. |
| tools/wta/Cargo.toml | Enables windows-sys console APIs via Win32_System_Console. |
| src/cascadia/TerminalApp/Tab.cpp | Logs when the agent pane’s connection is closed to surface backend death on the C++ side. |
![github-advanced-security[bot]](https://avatars.githubusercontent.com/in/57789?s=60&v=4){kind=small}
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…ail, spell - Tab.cpp: edge-trigger the agent-pane disconnect log on the open→closed transition (new `_agentPaneConnectionClosed` guard on Tab). The method runs on every pane connection-state change and on focus changes, so the unconditional log would spam terminal-agent-pane.log after a helper dies. - logging.rs: SetConsoleCtrlHandler install failure now logs at warn, not debug, so release (info) logs explain why teardown signals are missing rather than leaving it silent — the whole point is diagnosability. - spelling: allow the Win32 token PHANDLER (PHANDLER_ROUTINE) in apis.txt. Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
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The noun "diagnosability" isn't in cspell's base dictionary (though "diagnosable" is); reword the one occurrence to "diagnostic" to keep the spell-check gate green without a dictionary entry. Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Per PR review: SetConsoleCtrlHandler failure now logs GetLastError() in an `error_code` field, captured immediately before any other call can reset thread-last-error, so the warning distinguishes likely causes (no console attached vs. permission failure) instead of just stating it failed. Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
These five info! sites fired per-event, not per-lifecycle, and dominated the info logs (~2284 lines in a sample run). Info should be once-per- lifecycle / rare connection events; per-event detail belongs at debug (still available via WTA_LOG=debug). No information removed. - agent_sessions.rs "alive snapshot upgraded Historical row → Live" (1724x) - master/mod.rs "received helper session hook" (157x) - master/mod.rs "handling intellterm.wta/session_hook locally" (157x) - app.rs (agent_route) "applied" (127x) and "routing" (119x) Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
…es to debug Refines the earlier wholesale demotion of "received helper session hook": terminal/lifecycle transitions (SessionStarted/SessionStopped/PaneClosed/ ConnectionFailed) stay at info so field diagnosis of session-state bugs works from the default release log, while the high-frequency routine events (ToolStarting/ToolCompleted/Notification/resume bookkeeping) go to debug. The generic master-side dispatch breadcrumb stays at debug (it carries no event detail). Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Per PR review: only the helper is a ConPTY child of Windows Terminal and receives CTRL_CLOSE on pane/tab/window close. The master is spawned CREATE_NO_WINDOW and contained in a Job Object with KILL_ON_JOB_CLOSE (C++ SharedWta), so its routine teardown is a job reap — like TerminateProcess, no control event — and this handler does not make it traceable. Tighten the doc comment and the main.rs call-site comment to say so instead of implying both processes always observe these events. No behavior change (comment-only). Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Fills the two diagnosability gaps left after the console-ctrl-handler:
1. Rust panic hook (logging.rs): panics wrote only to stderr — invisible
for a ConPTY helper / CREATE_NO_WINDOW master — and the appender's
buffered tail was lost on a fatal panic. install_panic_hook() logs the
panic (message + location + thread) AND synchronously appends to
wta-panic.log (independent of the async appender, so it survives a fatal
panic), then chains the previous hook. Does NOT call shutdown_flush (that
would kill logging after a recoverable catch_unwind).
2. C++ master-death observability (SharedWta.cpp): the master is job-killed
(KILL_ON_JOB_CLOSE) and can't log its own hard death. Log from the parent
that observes it:
- _OnProcessExited: the wait callback fires for unexpected master exit
(crash/OOM/taskkill /F) — the external observer that makes silent
master deaths diagnosable. Deliberate teardowns never reach it.
- _CleanupLocked: record the deliberate KILL_ON_JOB_CLOSE teardown.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
- logging.rs: treat SetConsoleCtrlHandler's ERROR_INVALID_HANDLE (no console, expected for the CREATE_NO_WINDOW master / detached CLI) as debug; keep warn only for unexpected failures, so the warn can't reintroduce startup spam. - master/mod.rs: match the session-hook level decision on &event (borrow, not consume) — clearer intent; event is reused by the reducer below. - Tab.cpp: only walk the tree for the agent pane when something is closed, avoiding a second traversal on the common all-healthy path (still re-arms the edge-trigger guard correctly when nothing is closed). Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
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| # Workaround for the archival of check-spelling/check-spelling (archived 2026-06-16). | ||
| # On archival the maintainer flipped the action's runtime security poll (secpoll) | ||
| # to return the advisory 'Sorry' for v0.0.26 -- the final release -- which fatally | ||
| # to return a security advisory for v0.0.26 -- the final release -- which fatally | ||
| # cancels the workflow (exit 200) on every repo pinned to it. There is no fixed | ||
| # version to upgrade to. The action exposes an `ignore_security_advisory` input, | ||
| # but v0.0.26 never maps it into the secpoll step's environment, so passing it via | ||
| # `with:` is silently dropped. secpoll reads the INPUT_IGNORE_SECURITY_ADVISORY env | ||
| # var directly, so we set it here (composite action steps inherit workflow-level | ||
| # env). The value must exactly match the advisory text 'Sorry'. This keeps the | ||
| # (still-executable) archived action running. Caveat: if check-spelling.dev is ever | ||
| # taken down, secpoll's lookup returns empty/NXDOMAIN and this var being set will | ||
| # instead make secpoll fail ("...but there is no security advisory") -- at which | ||
| # env). secpoll requires this value to EXACTLY equal the current advisory text | ||
| # (the DNS TXT record at 26.0.0.security-status.secpoll.check-spelling.dev, minus | ||
| # its leading "3 " status prefix); any mismatch re-triggers the fatal exit 200 with | ||
| # "(ignore_security_advisory did not match)". The maintainer has already changed the | ||
| # text once (from "Sorry" to the value below), so if spelling starts failing fast | ||
| # (~6s) again, re-read that TXT record and update this string to match. This keeps | ||
| # the (still-executable) archived action running. Caveat: if check-spelling.dev is | ||
| # ever taken down, secpoll's lookup returns empty/NXDOMAIN and this var being set | ||
| # will instead make secpoll fail ("...but there is no security advisory") -- at which | ||
| # point this workflow must be reworked (remove the checker or pin a maintained fork). | ||
| env: | ||
| INPUT_IGNORE_SECURITY_ADVISORY: Sorry | ||
| INPUT_IGNORE_SECURITY_ADVISORY: "Sorry. https://github.com/jsoref/2026-06-16-credential-leak/blob/main/README.md" | ||
|
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Why
A reported "helper just stopped responding" incident turned out to be undiagnosable from the logs — not because the success path was under-logged (it was logged exhaustively), but because the teardown path was silent:
shutdown_flushonly runs on clean exits; theWorkerGuardlives in astaticthat neverDrops)._FocusAgentPane called.debug!lines flooded the logs (the master log was 631 KB ofdelivered=true), crowding out signal and pushing useful records out of the buffer faster.What
1. Rust — record why/when a process is torn down, and flush before dying
logging::install_ctrl_handler()— aSetConsoleCtrlHandlerthat logs which control event (CTRL_CLOSE/CTRL_LOGOFF/CTRL_SHUTDOWN/CTRL_BREAK) tore the process down and callsshutdown_flush()so the final records (incl. the existing transport-lostWARN) reach disk. ReturnsFALSE→ default handler still runs, termination behavior unchanged.main()right afterlogging::init, so it covers both helper and master.taskkill /F/ Task Manager "End task" delivers no control event and stays untraceable from inside the process.2. C++ — pane no longer blind to backend death
Tab::_UpdateConnectionClosedState()now_agentPaneLog(...)s when the agent pane's connection closes — correlating the UI-side disconnect to the millisecond with the Rust logs, and firing even when the master is gone and can't emitrestart_agent_pane.3. Success-path cleanup (
debug→trace)session_notification, autofixWtEvent/classified/cross-tab-drop). Kept one per-event breadcrumb atdebugand all connection/lifecycle logs intact.Verification
cargo +stable checkpasses; no warnings from the changed lines.wta-main_helper-*.log:WARN lifecycle: console control event received … ctrl_type=2 event="CTRL_CLOSE"— and it is the last line in the file, proving the pre-deathshutdown_flush()landed the buffered tail (the original blind spot).terminal-agent-pane.log:releasing wta-master pid=… (deliberate teardown via KILL_ON_JOB_CLOSE); no_UpdateConnectionClosedStatespam.🤖 Generated with Claude Code