bug#47711: bug#48841: bug#47711: [PATCH VERSION 2] Add new `completion-filter-completions` API and deferred highlighting

[Dmitry Gutov]

On 16.08.2021 16:21, Eli Zaretskii wrote:

> > > FWIW, I also don't understand how adding properties could cause a
> > > memory leak.  When a string is GCed, its properties get GCed as well,
> > > all of them.  Am I missing something?
> >
> > If you add string properties to all symbol names this memory will stay
> > alive for much longer than necessary.
>
> That's a very extreme example, something that I wouldn't expect a Lisp
> program to do, without removing the properties shortly thereafter.

And that *will* happen with Joao's approach, as soon as some package 
implements a Lisp completion backend in a certain (legal) fashion.

Or using one of a few different fashions, actually.

> And even that isn't a leak.
>
> Note that we already put all kind of properties (although not text
> properties) on symbols.

Those do not, generally, change over time.