On Sun, Apr 10, 2011 at 12:38:32AM -0700, Jakub Narebski wrote:
> Fraser Tweedale <frase@xxxxxxxxxxx> writes:
>
> > Subject: [PATCH] supply '-n' to gzip to produce identical tarballs
> >
> > Without the '-n' ('--no-name') argument, gzip includes timestamp in
> > output which results in different files. Important systems like FreeBSD
> > ports and perhaps many others hash/checksum downloaded files to ensure
> > integrity. For projects that do not release official archives, gitweb's
> > snapshot feature would be an excellent stand-in but for the fact that the
> > files it produces are not identical.
> >
> > Supply '-n' to gzip to exclude timestamp from output and produce idential
> > output every time.
> >
> > Signed-off-by: Fraser Tweedale <frase@xxxxxxxxxxx>
>
> Very good description, except subject line should denote which
> subsystem this commit affects, i.e.:
>
> gitweb: supply '-n' to gzip to produce identical tarballs
>
Thank you. Do I need to amend the message and resubmit the patch? (first
time submitting a patch to git; I used git send-email).
> Hmmm... gzip in gitweb's 'snapshot' action gets data compressed from
> standard input, not from filesystem. Isn't -n / --no-name no-op then?
> Just asking...
>
It is not no-op; I have tested to confirm this. I'm not sure whether
a file name is recorded in the stdin case, or if so what it is, but the
timestamp is recorded and that makes the difference.
> > ---
> > gitweb/gitweb.perl | 2 +-
> > 1 files changed, 1 insertions(+), 1 deletions(-)
> >
> > diff --git a/gitweb/gitweb.perl b/gitweb/gitweb.perl
> > index 46186ab..2ab08da 100755
> > --- a/gitweb/gitweb.perl
> > +++ b/gitweb/gitweb.perl
> > @@ -186,7 +186,7 @@ our %known_snapshot_formats = (
> > 'type' => 'application/x-gzip',
> > 'suffix' => '.tar.gz',
> > 'format' => 'tar',
> > - 'compressor' => ['gzip']},
> > + 'compressor' => ['gzip', '-n']},
>
> Perhaps it would be more clear to use
>
> + 'compressor' => ['gzip', '--no-name']},
>
> >
> > 'tbz2' => {
> > 'display' => 'tar.bz2',
> > --
> > 1.7.4.3
> >
>
Definitely, if the argument is the same (or even present) on all systems.
On FreeBSD and GNU both '-n' and '--no-name' are do the job, but an audit
of other systems should be done to ensure they don't break. I chose '-n'
as it seemed the more conservative choice.
> --
> Jakub Narebski
> Poland
> ShadeHawk on #git
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