bug#74104: 31.0.50; 'custom-set-faces' overrides face when no theme is loaded

[Protesilaos Stavrou <info@protesilaos.com>]

> From: Eli Zaretskii <eliz@gnu.org>
> Date: Wed, 30 Oct 2024 17:39:30 +0200
>
>> From: Protesilaos Stavrou <info@protesilaos.com>
>> Date: Wed, 30 Oct 2024 12:14:40 +0200
>> 
>> Dear maintainers,
>> 
>> When a theme is already enabled, 'custom-set-faces' has the effect of
>> adding face attributes on top of the existing ones. Those that were
>> present are not removed: they are blended with the new ones.
>> 
>> This, however, is not happening when no theme is loaded. In that
>> scenario, 'custom-set-faces' removes all the underlying face attributes
>> and keeps only those specified in the function call. I think this is a
>> mistake.
>
> custom-set-faces is used to set up customized faces in the user's init
> files: they are the forms written by Custom when the user decides to
> save the face customizations for future sessions.  So I don't think
> this is a mistake, and I don't see how we can change this without
> catastrophic effects on everyone's init files.

Indeed, I do not want to break anybody's setup or even make far-reaching
changes just for this. Do you think the difference in behaviour when a
theme is loaded versus when it is not is the intended design?

-- 
Protesilaos Stavrou
https://protesilaos.com