GNU bug report logs - #58158
29.0.50; [overlay] Interval tree iteration considered harmful

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Package: emacs;

Reported by: Gerd Möllmann <gerd.moellmann <at> gmail.com>

Date: Thu, 29 Sep 2022 05:30:02 UTC

Severity: normal

Found in version 29.0.50

Fixed in version 30.1

Done: Gerd Möllmann <gerd.moellmann <at> gmail.com>

Bug is archived. No further changes may be made.

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Message #5 received at submit <at> debbugs.gnu.org (full text, mbox):

From: Gerd Möllmann <gerd.moellmann <at> gmail.com>
To: bug-gnu-emacs <at> gnu.org
Subject: 29.0.50; [overlay] Interval tree iteration considered harmful
Date: Thu, 29 Sep 2022 07:29:25 +0200

In its current form, interval tree iteration works like this:

1. Call begin_iteration(T) to iterate over tree T
2. do stuff
3. Call end_iteration(T)

with the following rules:

- Begin_iteration and end_iteration must be paired.

- There can be only one iteration per tree at a time.  Nested iteration
  over the same tree is not supported (abort).

- No GC may happen in step 2.  This is because mark_buffer iterates over
  buffer overlays.

I think this is an exceedingly dangerous design.
This bug report was last modified 1 year and 311 days ago.

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