Bug#807270: mk-origtargz: create reproducible tarballs and --mtime option

[Osamu Aoki]

Hi,

Second thought ...

uscan/mk-origtargz/uupdate is not run during the binary package building
process.  Does the reproducible build aims to create source package in
reproducible way?

If reproducible build is aiming for binary build reproducibility,
changing behavior of uscan/mk-origtargz/uupdate has no impact.

On Mon, Dec 07, 2015 at 10:30:10PM +0900, Osamu Aoki wrote:

> On Sun, Dec 06, 2015 at 10:21:04PM +0100, Hans-Christoph Steiner wrote:
...
> > Whenever mk-origtargz is repacking a zipball, it should zero out the
> > timestamps in the tar format so that the process produces the same
> > tarball every time it runs.

Why you need this?  unzip preserves file timestamps inside of zip
archive.  Am I right?  Is this something we need to do for repacking of
tar.gz?

> > This can be done using tar's --mtime= flag.

Yah, if it is needed.

> > Additionally, it would be very useful if mk-origtargz also had a --mtime
> > option which forced the tarball to be repacked using the date given to
> > the --mtime="Wed Oct 28 10:12:27 2015 -0700" flag.  Here's an example of
> > how to do that in perl:
> > 
> > https://stackoverflow.com/a/16728218

Well ... it is simpler than this as long as we know what date to set.
Just run tar with --mtime option in the code with the reference file or
date string.

Regards,

Osamu