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Re: [Bug-tar] [PATCH] Do not fail when 'compress' is unable to provide s
From: |
Antonio Diaz Diaz |
Subject: |
Re: [Bug-tar] [PATCH] Do not fail when 'compress' is unable to provide sufficient compress ratio |
Date: |
Thu, 25 Apr 2013 17:49:14 +0200 |
User-agent: |
Mozilla/5.0 (X11; U; Linux i586; en-US; rv:1.7.11) Gecko/20050905 |
Paul Eggert wrote:
I think I'd rather have tar assume the gzip exit-status
convention, and depart from that only for bzip2 and lzip
(which don't use the convention). That's a bit simpler
and is more likely to match some random future compressor.
Only if the "random future compressor" continues repeating the errors of
the past.
Bzip2 and lzip follow a deeper convention; that any non-zero exit status
means failure[1]:
[1]http://www.gnu.org/software/bash/manual/html_node/Exit-Status.html#Exit-Status
"For the shell's purposes, a command which exits with a zero exit status
has succeeded. A non-zero exit status indicates failure. This seemingly
counter-intuitive scheme is used so there is one well-defined way to
indicate success and a variety of ways to indicate various failure modes."
Routing around gzip's quirks may be necessary, but if we begin
considering some non-zero exit statuses as success, chaos will develop.
The "--use-compress-program" is a general mechanism, not only for
compressors[2]:
[2]http://www.gnu.org/software/tar/manual/html_node/gzip.html#SEC132
"The '--use-compress-program' option, in particular, lets you implement
your own filters, not necessarily dealing with
compression/decompression. For example, suppose you wish to implement
PGP encryption on top of compression, using gpg"
And it happens that '2' is in the range gpg reserves for fatal errors[3]:
[3]http://www.gnupg.org/documentation/manuals/gnupg/GPG-Examples.html#GPG-Examples
"The program returns 0 if everything was fine, 1 if at least a signature
was bad, and other error codes for fatal errors."
So, please, don't break "--use-compress-program".
Best regards,
Antonio.
- Re: [Bug-tar] [PATCH] Do not fail when 'compress' is unable to provide sufficient compress ratio, Pavel Raiskup, 2013/04/22
- Re: [Bug-tar] [PATCH] Do not fail when 'compress' is unable to provide sufficient compress ratio, Paul Eggert, 2013/04/25
- Re: [Bug-tar] [PATCH] Do not fail when 'compress' is unable to provide sufficient compress ratio, Pavel Raiskup, 2013/04/25
- Re: [Bug-tar] [PATCH] Do not fail when 'compress' is unable to provide sufficient compress ratio,
Antonio Diaz Diaz <=
- Re: [Bug-tar] [PATCH] Do not fail when 'compress' is unable to provide sufficient compress ratio, Paul Eggert, 2013/04/25
- Re: [Bug-tar] [PATCH] Do not fail when 'compress' is unable to provide sufficient compress ratio, Pavel Raiskup, 2013/04/26
- Re: [Bug-tar] [PATCH] Do not fail when 'compress' is unable to provide sufficient compress ratio, Paul Eggert, 2013/04/26
- Re: [Bug-tar] [PATCH] Do not fail when 'compress' is unable to provide sufficient compress ratio, Pavel Raiskup, 2013/04/26
- Re: [Bug-tar] [PATCH] Do not fail when 'compress' is unable to provide sufficient compress ratio, Paul Eggert, 2013/04/26
- Re: [Bug-tar] [PATCH] Do not fail when 'compress' is unable to provide sufficient compress ratio, Pavel Raiskup, 2013/04/26
- Re: [Bug-tar] [PATCH] Do not fail when 'compress' is unable to provide sufficient compress ratio, Paul Eggert, 2013/04/26
- Re: [Bug-tar] [PATCH] Do not fail when 'compress' is unable to provide sufficient compress ratio, Pavel Raiskup, 2013/04/26
- Re: [Bug-tar] [PATCH] Do not fail when 'compress' is unable to provide sufficient compress ratio, Antonio Diaz Diaz, 2013/04/26
- Re: [Bug-tar] [PATCH] Do not fail when 'compress' is unable to provide sufficient compress ratio, Paul Eggert, 2013/04/26