bug#25458: 25.1; tar mode does not handle compressed archives without specific extensions

[Eli Zaretskii]

> Cc: 25458@debbugs.gnu.org
> From: Lars Ingebrigtsen <larsi@gnus.org>
> Date: Fri, 13 May 2022 16:12:24 +0200
> 
> Francesco Potortì <pot@gnu.org> writes:
> 
> > By looking at the comments on top of tar-mode.el, I get that it does not
> > rely on tar to get the archive listing, but reads the archive itself, so
> > correcting this problem does not appear straightforward to me...
> 
> (I'm going through old bug reports that unfortunately weren't resolved
> at the time.)
> 
> If Emacs had code to automatically recognise compressed data, I guess
> tar-mode could decompress the buffer before it started working on it.
> (Does Emacs have that?  I guess we could add stuff to
> `magic-fallback-mode-alist' or something in that region...)

But decompressing means, for most compression types, running an
external program on the file.  Or does OP suggest that we link Emacs
against libbz2, liblz4, liblzma, etc. to have these decompression
methods available in core?