fix: suppress xlings subprocess noise on Windows during bootstrap#57
Merged
Conversation
Two places in the first-run bootstrap path were missing output
redirection on Windows, causing xlings internal messages to leak
to the terminal:
1. ensure_init(): `xlings self init` ran without any output redirect
on Windows (Linux/macOS already had >/dev/null 2>&1). Now appends
platform::shell::silent_redirect (">/dev/null 2>&1" on Windows).
2. install_with_progress() fallback: the NDJSON interface command
had no stderr redirect on Windows (Linux/macOS had 2>/dev/null).
Now appends platform::null_redirect ("2>nul" on Windows).
After this fix, the first-run experience is consistent across all
three platforms — only mcpp's own status messages and progress bars
are shown; xlings internal output is fully suppressed.
4 tasks
Sunrisepeak
added a commit
that referenced
this pull request
May 23, 2026
* fix: seal child-process stdin on Windows (first-run hang) mcpp's first-run flow on Windows was hanging at xlings / xim / curl / git grandchildren that block on terminal stdin, forcing users to press Enter repeatedly to advance bootstrap and toolchain install. Root cause: process::seal_stdin was a no-op on Windows, and install_with_progress's direct-install path deliberately bypassed it. The POSIX side has had </dev/null sealing since PR #55 (macOS xcrun hang fix); Windows never received the equivalent fix. PR #57 only suppressed stdout/stderr noise (>/dev/null 2>&1) and did not touch stdin. Changes: - process.cppm: seal_stdin now appends "<NUL" on Windows (matches POSIX behavior). All capture / run_silent / run_streaming / run_passthrough callers gain the protection automatically. - xlings.cppm: install_with_progress's direct path explicitly appends "<NUL" on Windows. POSIX keeps the original behavior conservatively. - shell.cppm: silent_redirect docstring corrected — it never touched stdin, that's seal_stdin's job. Implementation unchanged. Regression coverage: - tests/unit/test_process_seal_stdin.cpp — deterministic reproduction test. Rebinds the test process's own stdin to an open, empty, never-closing pipe, then calls run_silent / capture / run_streaming with a child that reads stdin (more on Windows, cat on POSIX). Without the fix the child would block forever waiting on our pipe; with the fix it reads NUL / /dev/null and exits immediately. 5-second upper bound (real runs complete in <100ms). - ci-windows.yml — adds a step that launches mcpp via System.Diagnostics.Process with RedirectStandardInput=$true (parent holds the child's stdin open but never writes). Runs mcpp --version, mcpp build, mcpp run. Without the fix, any grandchild reading stdin blocks → step times out → CI fails. With the fix → all complete. * ci(windows): convert MCPP_SELF MSYS path → Windows path; rename pwsh $Args Two issues with the regression step from the previous commit (both showed up only on the actual Windows runner, not in local validation): 1. MCPP_SELF was set in an earlier bash step via `pwd` (git-bash) so the value is MSYS-style (e.g. /d/a/mcpp/...). Bash steps tolerate it but pwsh's `&` operator can't exec it ("not recognized as a name of a cmdlet, function, script file, or executable program"). Convert via cygpath -w before use. 2. `$Args` is a PowerShell automatic variable inside function scope; a `param([string]$Args)` does not bind cleanly. Renamed to $McppArgs to avoid the collision (also updated call sites).
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
1 participant
Add this suggestion to a batch that can be applied as a single commit.This suggestion is invalid because no changes were made to the code.Suggestions cannot be applied while the pull request is closed.Suggestions cannot be applied while viewing a subset of changes.Only one suggestion per line can be applied in a batch.Add this suggestion to a batch that can be applied as a single commit.Applying suggestions on deleted lines is not supported.You must change the existing code in this line in order to create a valid suggestion.Outdated suggestions cannot be applied.This suggestion has been applied or marked resolved.Suggestions cannot be applied from pending reviews.Suggestions cannot be applied on multi-line comments.Suggestions cannot be applied while the pull request is queued to merge.Suggestion cannot be applied right now. Please check back later.
Summary
ensure_init()missing output redirect on Windows —xlings self initinternal messages no longer leak to terminalinstall_with_progress()fallback missing stderr redirect on Windows — NDJSON interface stderr suppressedProblem
Windows first-run printed excessive xlings internal output (debug messages, extraction logs) while Linux/macOS were clean and silent. Two subprocess calls were missing platform-appropriate output redirection on Windows.
Test plan