Subject: bug#10990: 24.0.94; Uncompressing files

From: Dani Moncayo <[email-masked]>
Date: Mon, 12 Mar 2012 08:46:50 +0100

>> Well, it's obvious that there is no "gunzip" executable visible from
>> my environment.  I knew that.  And it is also obvious that I don't
>> need it.  The problem is not that my system is lacking an
>> uncompression program (I have "gzip -d"), the problem is that Emacs
>> (a) doesn't know how to invoke it, and (b) doesn't let me tell it how.
>
> gzip and gunzip are parts of the same package.  It is reasonable to
> assume that having one means you also have the other.

In the standard MinGW/MSYS distribution, "gzip" program is designed to
do both things.  In fact "gzip -h" shows:

 C:\emacs>gzip -h
 Usage: gzip [OPTION]... [FILE]...
 Compress or uncompress FILEs (by default, compress FILES in-place).
 [...]

So, in this case, "gunzip" is unnecessary.

BTW, I tried to copy "gzip.exe" as "gunzip.exe" as you suggested, but
it doesn't work, because Emacs invokes "gunzip" without "-d"
(obviously), so it doesn't work.

A workaround that does work (I've just tested it) is to create a file
"gunzip.bat" with a single line "gzip -d %1 %2 %3 %4", and store it in
the same folder as "gzip.exe".

> But it sounds like you don't actually want to solve your problem, but
> rather make some point about big bad Emacs.  Whatever.

No.  Evidently I want to solve my problem.

What happens it that, IMHO, the right solution in this case would be
to modify Emacs so that the command for uncompression would be
configurable, because in this case, the default configuration is not
the right one.

>> > Visiting compressed files uses "gzip -d", so it doesn't need gunzip.
>> > See lisp/jka-cmpr-hook.el.
>>
>> Then, why doesn't Emacs use that same method whenever it needs to
>> uncompress a file?
>
> Because dired uses a different code which was written by a different
> person, I guess.  That code needs a program name, not a shell command,
> so "gzip -d" will not do.
>
>> If Emacs was consistent in this regard and used "gzip -d" whenever it
>> need to uncompress a file, I would not have had any problem.
>
> I don't see why there should be a consistency in this case.

Neither I don't see why Emacs use different methods to perform the
same operation (uncompress a file).

>> > I submit that your system is misconfigured
>>
>> ???
>> I showed clearly that my system is capable of uncompressing files
>> compressed by Emacs.
>
> You have only half of a package installed.

No.  I have installed the standard MinGW/MSYS distribution, which has
support for uncompressing files.

-- 
Dani Moncayo