bug#53355: guix shell --check: confusing error message

[Ludovic Courtès]

Hi Chris,

Chris Marusich <cmmarusich@gmail.com> skribis:

> It turns out that it is probably not OK to rely on shell redirection in
> this case, after all.  For example, "dash does not support multi-digit
> file descriptors":
>
> https://bugs.launchpad.net/ubuntu/+source/dash/+bug/249620

Bah.  :-/

[...]

> To resolve this, I changed the code so that it just writes to a
> temporary file.  This is simple and more robust.  With the attached
> patch, I was able to use a command like the one above to verify that
> "guix environment --check" works correctly for Guix-built bash, dash,
> ksh, fish, zsh, and ash.  I also verified that it works for Fedora's
> /bin/sh and /bin/bash.
>
> What do you think of this file-based approach?  Supporting many
> different shells is pretty tricky, but I think this patch does a good
> enough job.

Like Maxime, I’d rather not create a temporary file.

I agree that Dash should be fixed, but in the meantime, we still want
our stuff to work with the broken Dash (it’s the default on
Debian/Ubuntu, isn’t it?).

I don’t have a better idea to offer though…

Ludo’.