fix(windows): suppress console window flashes in env probes, lazy installs, and platform.win32_ver() - #67690
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…talls, and platform.win32_ver()
From windowless processes (the pythonw gateway and the kanban workers it
spawns), three spawn paths flash visible console windows on Windows:
1. tools/env_probe.py::_run() ran its interpreter/pip probes
(python3 / python / pip / 'python3 -m pip' / PEP-668 check, ~5 per
worker start) without creationflags — one console flash per probe.
2. tools/lazy_deps.py had four spawn sites with the same defect:
'uv pip install', the 'pip --version' probe, ensurepip, and the
pip install fallback.
Both now pass creationflags=windows_hide_flags() (CREATE_NO_WINDOW on
Windows, 0 on POSIX) — stdio capture still works because the child is
hidden, not detached.
3. CPython 3.11's platform.win32_ver() unconditionally calls
_syscmd_ver(), which runs 'cmd /c ver' via
subprocess.check_output(shell=True) with no window suppression. Any
dependency touching platform.uname()/version()/platform() at import
time flashes one 'cmd' window per windowless process. New helper
_subprocess_compat.suppress_platform_ver_console() (Windows-only,
never raises) stubs platform._syscmd_ver so win32_ver() falls back to
sys.getwindowsversion().platform_version — verified byte-identical
platform.platform() output on CPython 3.11
('Windows-10-10.0.26100-SP0' either way). Called at the top of
hermes_cli/main.py, right after the hermes_bootstrap guard, before
heavyweight imports.
Verified on Windows 11 by polling EnumWindows at ~15 ms and attributing
new visible HWNDs to the suspect process tree (conhost child presence is
NOT evidence of a visible window — it appears even with
CREATE_NO_WINDOW). Tests: tests/tools/test_windows_native_support.py,
test_env_probe.py, test_lazy_deps.py, test_lazy_deps_durable_target.py —
153 passed; the 3 failures are pre-existing on upstream/main in a
Windows environment (POSIX-only assertions and NTFS chmod semantics).
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
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…run + add no-window tests (#67690 follow-up) Follow-up to the #67690 salvage (@m4r13y). The PR's tools/env_probe.py hunk was written against the old capture_output=True _run(); #67964/#67999 rewrote _run to temp-file capture on July 20, so that hunk no longer applied — but the rewritten _run still lacked creationflags and kept flashing one console per probe (~5 per kanban worker start) from windowless parents. Re-implement the one-line fix against the current shape: creationflags=windows_hide_flags() on the temp-file subprocess.run, preserving the #67964 grandchild-can't-wedge-the-pipe contract. Also add the tests the PR didn't ship, in tests/test_windows_subprocess_no_window_flags.py: - env_probe._run passes CREATE_NO_WINDOW and keeps temp-file (non-PIPE) stdout/stderr + DEVNULL stdin - lazy_deps uv install / pip --version probe / pip install fallback / ensurepip bootstrap all pass CREATE_NO_WINDOW - suppress_platform_ver_console: POSIX no-op (platform._syscmd_ver untouched, win32_ver() still returns), and simulated-Windows stubbing (echo stub installed, idempotent, never raises)
teknium1
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Jul 24, 2026
…run + add no-window tests (#67690 follow-up) Follow-up to the #67690 salvage (@m4r13y). The PR's tools/env_probe.py hunk was written against the old capture_output=True _run(); #67964/#67999 rewrote _run to temp-file capture on July 20, so that hunk no longer applied — but the rewritten _run still lacked creationflags and kept flashing one console per probe (~5 per kanban worker start) from windowless parents. Re-implement the one-line fix against the current shape: creationflags=windows_hide_flags() on the temp-file subprocess.run, preserving the #67964 grandchild-can't-wedge-the-pipe contract. Also add the tests the PR didn't ship, in tests/test_windows_subprocess_no_window_flags.py: - env_probe._run passes CREATE_NO_WINDOW and keeps temp-file (non-PIPE) stdout/stderr + DEVNULL stdin - lazy_deps uv install / pip --version probe / pip install fallback / ensurepip bootstrap all pass CREATE_NO_WINDOW - suppress_platform_ver_console: POSIX no-op (platform._syscmd_ver untouched, win32_ver() still returns), and simulated-Windows stubbing (echo stub installed, idempotent, never raises)
teknium1
added a commit
that referenced
this pull request
Jul 24, 2026
…run + add no-window tests (#67690 follow-up) Follow-up to the #67690 salvage (@m4r13y). The PR's tools/env_probe.py hunk was written against the old capture_output=True _run(); #67964/#67999 rewrote _run to temp-file capture on July 20, so that hunk no longer applied — but the rewritten _run still lacked creationflags and kept flashing one console per probe (~5 per kanban worker start) from windowless parents. Re-implement the one-line fix against the current shape: creationflags=windows_hide_flags() on the temp-file subprocess.run, preserving the #67964 grandchild-can't-wedge-the-pipe contract. Also add the tests the PR didn't ship, in tests/test_windows_subprocess_no_window_flags.py: - env_probe._run passes CREATE_NO_WINDOW and keeps temp-file (non-PIPE) stdout/stderr + DEVNULL stdin - lazy_deps uv install / pip --version probe / pip install fallback / ensurepip bootstrap all pass CREATE_NO_WINDOW - suppress_platform_ver_console: POSIX no-op (platform._syscmd_ver untouched, win32_ver() still returns), and simulated-Windows stubbing (echo stub installed, idempotent, never raises)
Contributor
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Merged via PR #70264 — your commit was cherry-picked onto current main with authorship preserved (rebase-merge). The |
randlee
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Aug 11, 2026
…run + add no-window tests (NousResearch#67690 follow-up) Follow-up to the NousResearch#67690 salvage (@m4r13y). The PR's tools/env_probe.py hunk was written against the old capture_output=True _run(); NousResearch#67964/NousResearch#67999 rewrote _run to temp-file capture on July 20, so that hunk no longer applied — but the rewritten _run still lacked creationflags and kept flashing one console per probe (~5 per kanban worker start) from windowless parents. Re-implement the one-line fix against the current shape: creationflags=windows_hide_flags() on the temp-file subprocess.run, preserving the NousResearch#67964 grandchild-can't-wedge-the-pipe contract. Also add the tests the PR didn't ship, in tests/test_windows_subprocess_no_window_flags.py: - env_probe._run passes CREATE_NO_WINDOW and keeps temp-file (non-PIPE) stdout/stderr + DEVNULL stdin - lazy_deps uv install / pip --version probe / pip install fallback / ensurepip bootstrap all pass CREATE_NO_WINDOW - suppress_platform_ver_console: POSIX no-op (platform._syscmd_ver untouched, win32_ver() still returns), and simulated-Windows stubbing (echo stub installed, idempotent, never raises)
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Summary
Three Windows console-window-flash fixes, all hit from windowless processes (a
pythonwgateway and every kanban worker it spawns). Each worker start was flashing a burst of visible console windows on the user's desktop.tools/env_probe.py—_run()calledsubprocess.runwithoutcreationflags. The probe sequence (python3/python/pip/python3 -m pip/ PEP-668 check) is ~5 spawns per worker start, each flashing a console. Now passescreationflags=windows_hide_flags().tools/lazy_deps.py— four spawn sites with the same defect (uv pip install, thepip --versionprobe,ensurepip, and the pip-install fallback). Same fix.platform.win32_ver()/_syscmd_ver()— CPython 3.11'splatform.win32_ver()unconditionally calls_syscmd_ver(), which runscmd /c verviasubprocess.check_output(shell=True)with no window suppression. Any dependency that merely touchesplatform.uname()/version()/platform()at import time flashes onecmdwindow per windowless process. New_subprocess_compat.suppress_platform_ver_console()helper (Windows-only, wrapped in try/except, no-op on POSIX) stubsplatform._syscmd_versowin32_ver()takes its documented fallback tosys.getwindowsversion().platform_version. Called at the very top ofhermes_cli/main.py, right after thehermes_bootstrapimport guard, before heavyweight imports.windows_hide_flags()returnsCREATE_NO_WINDOWon Windows and0on POSIX, and — unlike the detach flags — keeps stdio inherited, socapture_output=Truein all touched call sites keeps working.Verification
platform.platform()output is byte-identical with the stub active on CPython 3.11 / Windows 11 (Windows-10-10.0.26100-SP0either way; the fallback reads the same build number in-process viasys.getwindowsversion()).EnumWindowsat ~15 ms and attributing new visible HWNDs to the suspect process tree — note that aconhost.exechild is not evidence of a visible window (it appears even withCREATE_NO_WINDOW), so control runs with/without the flag were used.tests/tools/test_windows_native_support.py,test_env_probe.py,test_lazy_deps.py,test_lazy_deps_durable_target.py— 153 passed, 1 skipped. The 3 failures (test_no_op_on_posix,test_getattr_fallback_prefers_sigkill_when_present,test_readonly_target_reports_error) reproduce identically on a pristineupstream/maincheckout in the same environment — pre-existing POSIX-only assertions and NTFSchmodsemantics, unrelated to this change.🤖 Generated with Claude Code