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fix(xtask): launch non-exe commands through cmd.exe on Windows #79

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Merged
akroshg merged 3 commits into from
Mar 7, 2026
Merged

fix(xtask): launch non-exe commands through cmd.exe on Windows #79

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3a54216
fix(xtask): launch non-exe commands through cmd.exe on Windows
akroshg Mar 6, 2026
e86fafc
fix(xtask): resolve .cmd/.bat via which and add Job Object safety net
akroshg Mar 6, 2026
b3d25a7
test(xtask): verify build_command resolves pnpm on Windows
akroshg Mar 6, 2026
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13 changes: 11 additions & 2 deletions xtask/src/process.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -30,9 +30,18 @@ pub fn spawn_child(label: &str, cmd: &str, args: &[&str], cwd: &Path) -> Option<
console::style(label).cyan().bold(),
);

let mut command = Command::new(cmd);
// On Windows, non-.exe commands (e.g. .cmd/.bat scripts like pnpm) must be
// launched through cmd.exe because CreateProcessW only resolves .exe files.
let mut command = if cfg!(windows) {
let mut c = Command::new("cmd");
c.arg("/c").arg(cmd).args(args);
c
} else {

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When cmd.exe /c is used, individual arguments in the args slice are passed as separate arg() calls, but cmd.exe reassembles them into a single command line string using its own quoting rules. If any argument or the cmd value contains spaces, special characters (&, |, >, <, ^, %, !), or quotes, cmd.exe may misinterpret them, leading to incorrect behavior or potential argument injection. The current callers only pass simple strings like "start:server", so this is not an immediate problem, but it is a latent hazard as the function is public and could be called with arbitrary arguments in the future. Consider documenting this limitation or using std::os::windows::process::CommandExt::raw_arg to bypass cmd.exe's re-quoting.

Suggested change
// On Windows, non-.exe commands (e.g. .cmd/.bat scripts like pnpm) must be
// launched through cmd.exe because CreateProcessW only resolves .exe files.
let mut command = if cfg!(windows) {
let mut c = Command::new("cmd");
c.arg("/c").arg(cmd).args(args);
c
} else {
// Spawn the requested command directly; on Windows we rely on PATH/PATHEXT
// resolution so that shell wrapper scripts (e.g. .cmd/.bat) are located
// without going through `cmd.exe`.
let mut command = {

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let mut c = Command::new(cmd);
c.args(args);
c
};

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When cmd.exe /c is used to wrap the command on Windows, the Child handle returned by command.spawn() refers to the cmd.exe process, not the actual target process (e.g. pnpm). As a result, send_graceful_stop sends CTRL_BREAK_EVENT to cmd.exe's process group ID (the cmd.exe PID), not to the real subprocess's group. Because cmd.exe /c spawns the real process in its own context and does not forward CTRL_BREAK_EVENT, the graceful shutdown mechanism (lines 229–238) silently fails: only cmd.exe is signalled, and the real long-running process (e.g. a pnpm dev server) is left running or must wait for the 3-second timeout to be force-killed.

A more robust approach for Windows is to use where.exe or std::env::var("PATHEXT") to locate the actual .cmd/.bat file and pass its full path to Command::new, or to use the which crate to resolve the executable. Alternatively, if cmd.exe /c must be kept, the process group setup and graceful-stop logic need to account for the extra cmd.exe wrapper layer.

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command
.args(args)
.current_dir(cwd)
.stdin(Stdio::inherit())
.stdout(Stdio::inherit())
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