Re: MPS: weak hash tables

[Eli Zaretskii <eliz@gnu.org>]

> From: Gerd Möllmann <gerd.moellmann@gmail.com>
> Cc: pipcet@protonmail.com,  eller.helmut@gmail.com,  yantar92@posteo.net,
>   emacs-devel@gnu.org
> Date: Sun, 07 Jul 2024 16:15:54 +0200
> 
> Eli Zaretskii <eliz@gnu.org> writes:
> 
> >> From: Gerd Möllmann <gerd.moellmann@gmail.com>
> >> Cc: pipcet@protonmail.com,  eller.helmut@gmail.com,  yantar92@posteo.net,
> >>   emacs-devel@gnu.org
> >> Date: Sun, 07 Jul 2024 13:19:09 +0200
> >> 
> >> Eli Zaretskii <eliz@gnu.org> writes:
> >> 
> >> >> Balancing only changes the tree structure, without freeing nodes, AFAIR.
> >> >> But that could be wrong. It's been a long time since I looked closer at
> >> >> that tree.
> >> >
> >> > We free nodes in sweep_intervals.
> >> 
> >> I think that is handled in igc.c by intervals becoming unreachable.
> >
> > They will not become unreachable unless we unchain them, as is done in
> > sweep_intervals.  Right?
> 
> It starts with the root of a tree becoming unreachable, say a string's
> intervals become unreachable because the string is unreachable. By that,
> the root's children are unreachable and so on.

I thought about the case where the string or the buffer are still
alive, but some of their intervals are no longer used because of
changes in the text properties.