Re: [found the culprit]

[Stefan Monnier <monnier@IRO.UMontreal.CA>]

>> > I do think that Z on a compressed Tar archive, be it a .tar.gz or .tgz
>> > file, should not by default unpack the archive.  We could have a
>> > special prefix arg to request that, and by default we should just
>> > uncompress the file.  But that's a different issue.
>> 
>> FWIW, I consider ".tar.gz" (or "tar.lz", ...) as the archive format
>> (rather than as a combination of tar and compression): since the tar
>> format does not support random access anyway there's very little benefit
>> to having it uncompressed (unless the content can't be compressed
>> e.g. because it's already compressed).
>
> But then 'Z' shouldn't invoke unpacking, because it is documented as
> "uncompress" operation.

But if you consider ".tar.gz" in the same way as ".zip" (i.e. the
compression is indivisible from the archiving), then does that mean you
think it should signal an error when asked to uncompress such a file?

AFAICT Emacs has unpacked .tar.gz when asked to uncompress them for many
years and noone has complained about it so far.  I think it's the most
natural thing to do.  The only recent change in this regard is to adjust
the behavior on .tgz so it works like .tar.gz (the old behavior was
really odd to me: the name ".tgz" even more strongly hints at the
desire to treat archiving and compression as indivisible, so it was
very strange for Emacs to only uncompress rather than unpack it when the
same operation .tar.gz unpacked it).


        Stefan