Quoted program names are not handled properly for CMD

[m-haug]

watchexec 1.22.3 does not handle cmd quoting properly on Windows.

This came up when investigating tectonic-typesetting/tectonic#1003. See there for the actual command that caused the issue. However, the issue also reproduces with the watchexec binary:

$ watchexec --version
watchexec 1.22.3 (eb19f83 2023-05-14)                                                                                                         commit-hash: eb19f837612a046d58173efae7e3b0825d475313
commit-date: 2023-05-14
build-date: 2023-05-14
release: 1.22.3
features:
$ watchexec -vvv --log-file --shell cmd -- '"C:\Users\Markus Haug\scoop\apps\tectonic\current\tectonic.exe"' -X build --open
Der Befehl "\"C:\Users\Markus Haug\scoop\apps\tectonic\current\tectonic.exe\"" ist entweder falsch geschrieben oder                           konnte nicht gefunden werden.
[[Command exited with 1]]

I've attached the log file of that run.

After some digging, I found the Command::raw_arg method. The documentation suggests that this a known issue when passing arguments via cmd.exe /C. On Windows, this match arm should probably be handled specially. Unfortunately, tokio does not seem to have the raw_arg method on its Command, so this would probably require a conversion from std's Command.

If you like, I can open a PR for this.

[m-haug]

I've opened tokio-rs/tokio#5810 to hopefully get raw_arg on tokio's Command.

[passcod]

As a workaround, I think use --shell none and handling args manually would work?

[m-haug]

In general/when using watchexec as a binary, that would work, I believe. But for the tectonic use case (watchexec), that workaround would require preprocessing the arguments using something like shlex, which may be too much effort for a temporary workaround.

[passcod]

Yeah, fair enough. If there's a workaround that can be done in the library code until the tokio support lands I'd be happy to merge it.