Re: GUIX_EXTENSIONS_PATH pattern

[Ricardo Wurmus <rekado@elephly.net>]

Hi,

sorry for the delay!

zimoun <zimon.toutoune@gmail.com> writes:

>>> We can change this, but we’d need to agree on an as yet unused directory
>>> as the root for extensions.
>
>> We could say that:
>>
>>  1. the prototype of GUIX_EXTENSIONS_PATH is path/to/guix
>>  2. the folder /extensions is implicitly appended 
>>  3. ~/.config/guix is implicitly appended
>
> Do we agree on this default?  Which implies…

I’m really not sure.

1. do you mean “share/guix” here?

2. I don’t know if this is a good idea, because the extensions really
are in the “extensions” sub-directory.  Why would the variable refer to
a more generic parent directory?

3. My opinion is that ~/.config/guix should not get special treatment.
People can use different profiles for “guix pull”.

>> The patch attached does that.  But, the definition of the package ’guix’
>> needs to be tweaked (not done) in agreement, especially:
>>
>> --8<---------------cut here---------------start------------->8---
>>       (native-search-paths
>>        (list (search-path-specification
>>               (variable "GUIX_EXTENSIONS_PATH")
>>               (files '("share/guix/extensions")))))
>> --8<---------------cut here---------------end--------------->8---
>
> …and…
>
>>>> Moreover, it could nice to have GUIX_EXTENSIONS_PATH look by default
>>>> in ~/.config/guix/extensions, i.e., by default
>>>> GUIX_EXTENSIONS_PATH=~/.config.
>>>
>>> The last part of this sentence is what I meant above: we need to avoid
>>> that, because that would cause
>>> ~/.config/guix/current/share/guile/site/3.0/guix/scripts/ to be included
>>> in the search for extensions.
>>
>> It is easy to filter out by adding rules in ’extensions-directories’. :-)
>
> …that.
>
> To me, the easiest is to fix the module name as ’(guix extensions foo)’
> and since that is fixed, GUIX_EXTENSIONS_PATH should not declare
> explicitly ’/extensions’.

Perhaps we can invite some other people to comment on this.  I have
become confused about what is the best way forward (which is one of the
reasons why it took me so long to reply).

> BTW, I have not tried to adapt and makes it work for extension as
> subcommand.  I have in mind: “guix git log” or “guix system foo”.  Well,
> these subcommands are not defined as ’define-command’ but we could take
> this road.  WDYT?

I haven’t really thought about this, but extensions for sub-commands of
sub-commands currently only work by replacing the parent command, so
they cannot be composed.

We probably could add a mechanism to that (guix extensions system foo)
would extend the “guix system” command, but this would require more work
as the “system” command is responsible for dispatching to the
sub-command.  I don’t know if there’s a good generic way to implement
this.  “guix system foo” could bypass the “guix system” entry point if
(guix extensions system foo) exists, but this may have unwanted
consequences.

-- 
Ricardo