bug#59935: 29.0.60; project-list-buffers is slow

[Dmitry Gutov]

On 11/12/2022 20:17, Eli Zaretskii wrote:
> Why not leave alone that additional PREDICATE
> argument of list-buffers-noselect, and add a feature where the
> BUFFER-LIST argument could be a function?  That's be a compatible
> change.  Just keep the PREDICATE argument and the code which supports
> it, and document that if PREDICATE is a function, BUFFER-LIST cannot
> be a function.

While that should work, that change would *also* change the signature. 
Though in a safer way, yes.

Are you worried about some out-of-tree clients that started using the 
new feature in the meantime?

Otherwise, this change could be split into two steps:

- Rollback that signature to pre-commit 125b5684c (i.e. revert its part 
in buff-menu.el). This is something we usually considered to be safe.

- Add new change that allows BUFFER-LIST to be a function.