Re: how to track down "invalid face attribute" errors?

[Eli Zaretskii]

> From: Eric S Fraga <e.fraga@ucl.ac.uk>
> Date: Sun, 25 Sep 2022 13:03:03 +0100
> 
> some package I'm using is leading to errors of the form
> 
>   Invalid face attribute :foreground nil [54 times]
> 
> can anybody suggest how I can track down which package/function is
> causing this?  Debugging on error doesn't catch this.  All web searches
> lead me to specific packages that have had this error in the past (none
> of which I use).

Can you run Emacs under GDB?  If so, put a breakpoint on the line in
xfaces.c which emits this message, and use the backtrace to find out
which face causes it.