subprocess.run(["git", ...], timeout=...) deadlocks on Windows: run()'s
post-timeout cleanup calls an unbounded communicate() after killing git.
Killing the PATH-resolved launcher can leave a suspended descendant git.exe
holding duplicates of the captured stdout/stderr handles, so the pipes never
reach EOF and the reader-thread join blocks forever — leaking a process +
two reader threads per fired timeout (the accumulating git.exe load behind
Windows Defender CPU spikes).
Two fail-open probe call sites had this identical flaw:
- tui_gateway/git_probe.py::run_git — on the Desktop agent-build path
(_start_agent_build -> _session_info -> branch() -> run_git), where the
hang turned an optional branch label into "agent initialization timed
out" (#68609).
- agent/coding_context.py::_git — hangs the agent turn inside
build_coding_workspace_block under an ACP host (#66037).
Consolidate both onto one shared bounded_git_probe() in
hermes_cli/_subprocess_compat.py (both files already import from there, so
no new import surface):
- explicit communicate(timeout), then on ANY failure a tree-kill —
proc.kill() AND, on Windows, best-effort taskkill /T /F so the suspended
descendant that holds the pipe writers dies too — plus a bounded 1s
post-kill drain; if the pipes are still held they're abandoned (the
orphaned reader threads are daemonic and cost nothing).
- fail open to "" on every path: spawn error, timeout, kill() raising
(access denied / already reaped — a raise inside the except handler
previously escaped the contract), and non-timeout communicate() failures
now also terminate the child instead of leaving it running.
- the taskkill spawn can't re-enter the deadlock class: it captures no
pipes (DEVNULL), so its own timeout cleanup has no reader threads to join.
Normal-path spawn contract is preserved byte-for-byte: PIPE/PIPE/DEVNULL,
text + utf-8 errors="replace", hidden-window creationflags on Windows only,
nonzero returncode -> "". Each call site keeps its own timeout (1.5s / 2.5s).
Supersedes #68622 (Sora-bluesky — git_probe fix + tree-kill) and #66038
(iamwongeeeee — coding_context fix), folding both into one shared helper so
the two sites can't drift and every timeout tree-kills the descendant. Tests
consolidated onto the helper, incl. the previously-missing assertion that a
Windows timeout escalates to taskkill /T /F.
Co-authored-by: Sora-bluesky <sora.bluesky.dev@gmail.com>
Co-authored-by: iamwongeeeee <wykim777@naver.com>
Co-authored-by: Claude Fable 5 <noreply@anthropic.com>
These tests patch `<module>.subprocess.run`, which is the shared `subprocess`
module singleton, so the patch is process-wide. Importing `tui_gateway.server`
runs `prefetch_update_check()` at import time, spawning an unnamed daemon thread
(`Thread-N (_run)`) that shells out to `git ... origin` (`text=True, timeout=5`).
That call races the test and lands in the captured list, intermittently failing
`test_tui_gateway_fuzzy_file_listing_hides_git_windows` with either
`KeyError: 'creationflags'` (the daemon's git call has no creationflags) or a
call-count mismatch (3 git calls captured, not 2). It only reproduced under the
parallel test harness because of the extra concurrency/timing.
Filter captured calls to the distinctive argv tokens of the call under test
(`--show-toplevel`, `ls-files`, `branch --show-current`, `diff`, `rg`,
`taskkill`) and read `creationflags` via `.get`, mirroring the existing
hardening on `test_gateway_pid_scan_hides_wmic_and_powershell_windows`. The
production code is unchanged; this is a test-isolation fix.
test_gateway_pid_scan_hides_wmic_and_powershell_windows flaked once in CI
(slice 7/8) with 'KeyError: creationflags' while passing 15/15 under exact
CI-parity locally. The positional 'kwargs["creationflags"]' indexing raises
a bare KeyError the moment any stray subprocess.run call is captured, masking
the real contract. Filter captured calls to the two intended Windows console
spawns (wmic + PowerShell fallback) and assert each is windowless via
.get('creationflags'); a leaked/extra call now surfaces as a readable
len-mismatch with the full captured list, not a cryptic KeyError.
windows_hide_flags() already returns 0 on POSIX (and creationflags=0 is
the no-op default there, exactly how server.py::_list_repo_files does it),
so drop the IS_WINDOWS import + ternary/one-use-dict gating and just pass
creationflags=windows_hide_flags() directly. Tests lose the now-pointless
IS_WINDOWS monkeypatch.
The #54236/#54417 backend git/gh sweep routed git_probe, the repo-file
picker, coding_context, context_references, copilot_auth, and the gateway
process scans through CREATE_NO_WINDOW, but two sibling spawn legs that
also run inside the console-less desktop/gateway backend were missed:
- tools/checkpoint_manager.py `_run_git` (and the one-shot `git init
--bare` in `_init_store`) — when checkpoints are enabled, every
file-mutating turn fires multiple bare `git` calls (status, add,
write-tree/commit-tree, update-ref). Spawned from a parent with no
console (Electron spawns the backend with windowsHide → CREATE_NO_WINDOW),
each one allocates its own conhost window → a flurry of terminal popups.
- tools/skills_hub.py `GitHubAuth._try_gh_cli` — `gh auth token`, the same
bug class as the already-fixed copilot_auth gh probe.
Route both through `windows_hide_flags()` (no-op on POSIX), matching the
established per-site pattern. Tests added to
tests/test_windows_subprocess_no_window_flags.py.
main (cb982ad99) wired windows_hide_flags() into the auxiliary git/gh/wmic/
bash/powershell/taskkill legs but left two it didn't reach, plus the Electron
backend-launch leg it explicitly deferred. Cover them the same way:
- apps/desktop/electron/main.cjs: getNoConsoleVenvPython resolves the BASE
pythonw.exe instead of the venv Scripts\pythonw.exe shim, which re-execs a
console python.exe and flashes a conhost the desktop backend can't suppress.
Both backend creators put the venv site-packages on PYTHONPATH so imports
still resolve under the base interpreter. (main's commit said this Electron
leg "needs a Windows-tested change of its own".)
- tools/tts_tool.py, tools/transcription_tools.py, plugins/platforms/discord:
ffmpeg conversions (voice notes / TTS / STT) via windows_hide_flags().
- plugins/platforms/whatsapp: netstat + taskkill bridge-port cleanup via
windows_hide_flags().
All no-ops on POSIX. Tests assert the base-pythonw preference and the ffmpeg
legs pass CREATE_NO_WINDOW.
