Re: [found the culprit]

[Mike Kupfer]

Davis Herring wrote:

> > `Z' should be its own inverse.
> 
> This is a reasonable principle, but there is a reason to deviate from
> it here.  The uncompressed tar format is so rarely used (partly
> because of the lack of actual tape drives, and partly because of
> change in the relative cost of CPU cycles and storage space) that
> having a convenient key to get _to_ it is unimportant.

Perhaps to you, or perhaps even to most Emacs users.  Me, I'd like to
get the .tar file back.  It doesn't need to be the default behavior--I'd
be happy if there were a user option that would let me control whether
the file is unpacked or not.

There are a couple problems with the current behavior that are mentioned
in #25611, but which I haven't seen covered in the current discussion.

1. The prompt doesn't say anything about unpacking.

2. It's possible to silently overwrite user files, both because of (1)
and because the code makes assumptions about the contents of the tar
file.

3. There is a potential exploit due to (2).

I don't list these as arguments against the current behavior, just as
things that should be fixed.

mike