bug#55205: 28.1.50; completion--replace illegally mutates completion candidates

[Dmitry Gutov]

On 02.05.2022 17:27, Eli Zaretskii wrote:
> > Date: Mon, 2 May 2022 12:46:00 +0300
> > Cc:mail@daniel-mendler.de,larsi@gnus.org,monnier@iro.umontreal.ca,
> >   55205@debbugs.gnu.org
> > From: Dmitry Gutov<dgutov@yandex.ru>
> >
> > On 02.05.2022 05:23, Eli Zaretskii wrote:
> > > Collection can include functions, and how do you copy that?
> > Collection can be a function, not "include functions". You fetch the
> > list of strings using that function (for the given input) and then make
> > a deep copy of that.
> So I need to call that function twice, is that it?  It is normally
> called by the completion machinery out of my control.

You only use the function at the "fetch the list" step.

How many times it is called in total, is a harder question (due to 
implementation details, sometimes suboptimal), but that number shouldn't 
have to change.