I have hit this problem the second time now so I think it is important
to keep concerned people informed.


rrs@priyasi:/var/tmp/Debian-Build/Result/home:ritesh:branches:foobar:busterbootstrap:target/xz-utils/xz-utils (master)$ gbp import-dsc ../xz-utils_5.2.2-1.3.dsc
gbp:error: Git command failed: Couldn't commit to 'pristine-tar' with upstream '78070151ccd87648d5f2c3b6a8c0ad4bf9685f03': pristine-xz failed to reproduce build of /var/tmp/Debian-Build/Result/home:ritesh:branches:foobar:busterbootstrap:target/xz-utils/xz-utils_5.2.2.orig.tar.xz
(Please file a bug report.)
pristine-tar: failed to generate delta
13:27 ♒♒♒    ☹ 😟=> 1


The steps are simple:
1. gbp init
2. apt -t testing source xz-utils
3. gbp import-dsc

IIRC, this felt more like an issue with xz-utils instead but I really
did not have enough data points to finger point to it.

If there is more information I could provide, please do mention it in
this bug report

Hi!

Is anyone having success using pristine-tar with upstream tarballs that use xz?

I see multiple reports that look very similar:
https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=918663
https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=851291
https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1041465
https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1110375

I also noticed there was this issue in xz itself:
https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1063252

Wild guess: could it be related that xz supports multiple compression
levels and they are not part fo the metadata currently?

- Otto

I'm not sure it was really necessary to cross-post this across
several bugs while also CC'ing random developers (I don't think I've
ever interacted with any of the bugs you mention above).

To answer your question, libvirt and libvirt-dbus are both using
pristine-tar to import xz-compressed upstream tarballs and I'm not
aware of that ever causing any issues.