Re: tramp (2.2.13.25.2); setting GZIP environment variable breaks tramp

[Francesco Potortì]

>> Recently gzip started to emit a warning (on stderr, I believe) saying
>> that setting the GZIP env var is deprecated.
>>
>> I never cared too much about it until tramp stopped working.  After some
>> time, I discovered that GZIP was the culprit.
>>
>> For example, both with the ssh and scp methods, reading a remote file
>> works, but writing it back after modification fails.
>>
>> Maybe tramp could detect GZIP's warning and dtrt
>
>Hmm, I cannot test it locally. My Ubuntu 18.10 carries gzip 1.6, which
>doesn't emit such a warning.
>
>Could you please check, whether "gzip -q ..." suppresses such a warning
>for you? I would add "-q" then for the gzip calls inside Tramp.

No, the warning is there even with -q.

>You could also manipulate Tramp and test it. Tweak the constant
>tramp-inline-compress-commands accordingly.

I see two ways to work around this: send stderr to /dev/null or unset
GZIP:

$ export GZIP=-9
$ echo | gzip -c >/dev/null
gzip: warning: GZIP environment variable is deprecated; use an alias or script

$ echo | gzip -c >/dev/null 2>/dev/null

$ echo | env --unset=GZIP gzip -c >/dev/null


So one of these would be a simple solution.  But I wonder: since tramp
checks for a working compression program, why doesn't it realise right
from the start that gzip does not work?  I think it should.


One more thing, since I am at it: maybe nowadays the first compression
program to check should be lzop, which is fast


Thankyou for maintaining this