Re: ‘guix environment’ vs. ‘.bash_profile’

[Ricardo Wurmus <rekado@elephly.net>]

Ludovic Courtès <ludo@gnu.org> writes:

> Hi!
>
> Danny O'Brien <danny@spesh.com> skribis:
>
>> Brendan Tildesley <mail@brendan.scot> writes:
>>
>>> Doom Emacs has a tool `doom doctor' for diagnosing common
>>> errors. Perhaps there
>>> could be a `guix doctor' that would check for such things. `guix
>>> offload test'
>>> is already somewhat like that but for offloading, althought it could
>>> improve.
>>> Any bug report from a user where the solution is to tell them to fix
>>> their
>>> environment instead of changing guix could also have a check added
>>> to guix
>>> doctor.
>
> Interesting.  Any idea how this particular issue could be checked for?
> If we can come up with an automated way to determine that “something’s
> wrong”, we might as well get ‘guix environment’ to display a hint.

The checks would have to be pretty self-contained and carefully ordered.
Imagine LD_LIBRARY_PATH is set to something terribly incompatible: we
might not even be able to launch Guile then!  These tests would also
have to work for older Guixes, e.g. when “guix pull” was used but the
effective “guix” command is /usr/local/bin/guix or even
~/.guix-profile/bin/guix (from a misguided invocation of “guix install
guix”).

This is really tricky to get right when you can’t trust the execution
environment.

> For example, ‘guix’ displays hints for unbound variables or misnamed
> modules because these are common mistakes.

I think these hints are excellent!  I’m often surprised at how good and
useful they are.

I have sometimes been frustrated with the lack of *any* output in case
of errors.  It is possible to get Guix to just print an obscure error
and get neither a backtrace nor a hint.  Of course I can’t remember now
how to replicate this, but this could be a good exercise for new
contributors: do whatever you can to make Guix barf!

One thing that usually only hits contributors is a barrage of unrelated
error messages (with repeated hints to include different modules) that
culminate in something silly like “unknown package” for an unrelated
package that obviously exists.  I’m sure you’ve also encountered this
before while adding or upgrading packages.

-- 
Ricardo