Re: Questions regarding substitutes with debug output

[Maxim Cournoyer <maxim.cournoyer@gmail.com>]

Hello,

Olivier Dion <olivier.dion@polymtl.ca> writes:

> On Fri, 22 Apr 2022, Maxim Cournoyer <maxim.cournoyer@gmail.com> wrote:
>>> I require debugging symbols of multiple packages.  Some of them
>>> already have a debug output from the main guix channel, but others
>>> don't.  So I had in mind to make a channel and publish the
>>> substitutes with the debug outputs.
>>
>> In general, if you need debug symbols for something, I think it's OK
>> to contribute adding them to Guix proper (in a debug output), unless
>> they make like >= 1 GiB (as I can imagine may be the case for IceCat).
>
> Okay I will try.  I'm not sure how easy it is so add debug symbols to some
> packages e.g. git, nginx.  In any case I need them, so I will contribute
> back to the main channel if it works.

When the package uses the gnu-build-system, it is usually just adding a
"debug" outputs and the copying of the stripped symbols to this output
is taken care of automatically.  Some packages use their own flags or a
release build without symbols in which case just adding "debug" alone
won't be enough.

>>>   How could I make sure that Guix use my version of Firefox over the one
>>>   defined by the main channel?  My guess is to change the name of my
>>>   package to something like "my-firefox".  But it would be nicer if I
>>>   don't have to do so.  Perhaps there's a way to force channel
>>>   preference?
>>
>> Channels can only extend, not override the default Guix channel (the
>> world would be a bit of a mess if it did).  So the easiest path is to
>> use a different name; alternatively for graph rewriting you could use
>> the various APIs to effect package transformations.
>
> Would be nice to have some way to specify channel in a package
> specification.  I don't think that it would break things if we
> considerer channels as namespaces, i.e. different graph.  A
> specification like:
>
>   {channel}package@version:output
>
> would be useful.  For now I will just rename them to "my/package".

That could be neat, yes.  I wonder how easy/difficult its implementation
would be.

Thanks,

Maxim