Subject: bug#79280: package installation leaks tar-mode data buffers

From: Stefan Monnier <[email-masked]>
Date: Thu, 21 Aug 2025 15:15:57 -0400

>> A more principled solution might be to make buffers GC-able like any other
>> object, at least optionally. Exactly how to do this can be discussed but
>> maybe just being able to remove a buffer from Vbuffer_alist would do. (We
>> have one buffer like that, Vprin1_to_string.) Of course, we'd have to
>> teach the GC to destroy buffers. Fkill_buffer is depressingly long and
>> complicated and should be broken up in smaller parts.
>
> There's no way Emacs could know whether a buffer is still needed.
> Users that want to get rid of buffers that were not accessed for too
> long can use the midnight.el features to do that.  So I don't think we
> need to add any automation here.

I don't think Mattias is suggesting to GC normal buffers, but rather to
allow the creation&use of anonymous buffers (and then to make `tar-mode`
use such an anonymous buffer for its auxiliary buffer).

It's been suggested/mentioned several times in the past, but it's not
clear how that would work.  Maybe we could allow `buffer-name` to be `t`
for buffers which have no name yet are still live, and then collect (and
find solutions for) all the problems this introduces.

        Stefan