Update report: ===========
Downloaded xdelta3 source code from: https://code.google.com/p/xdelta/downloads/detail?name=xdelta3-3.0.8.tar.xz&can=2&q= and build it locally with unxz xdelta3-3.0.8.tar.xz tar xf xdelta3-3.0.8.tar cd xdelta3-3.0.8/ ./configure --prefix=/home/ibanez/local mkdir ~/local make -j8 make install Then rerun the self-comparison test: ~/local/bin/xdelta3 -s luisrecreated2.tar luisrecreated2.tar delta3 and got: 10189 bytes delta3 Which is a reasonably small file, for the output of a self-comparison. Then run the initial comparison of the tar file generated by git-buildpackage vs the upstream tar, as ~/local/bin/xdelta3 -s luisrecreated2.tar tarball.tar delta4 and got a more reasonable output this time: 979838 bytes delta4 So, it looks like, xdelta version 3 has addressed the problem. However the syntax of its options have changed. (see the -s flag instead of the previous "delta" sub-command). What do we do ? ============= I could generated the delta with xdelta3 and populate the pristine-tar branch, but, it is unclear whether this will do any good if the other systems that will attempt to build the package are still using xdelta 1.1.3. Suggestion A: =========== >From reading the gbp.conf man page: http://honk.sigxcpu.org/projects/git-buildpackage/manual-html/gbp.cfgfile.html It seems that we could put a customized gbp.conf file in this specific repository, by placing it in: debian/gbp.conf : per repository/branch configuration To change the default behavior and exclude the use of pristine-tar (and hence the downstream use of xdelta), by using the setting: [DEFAULT] pristine-tar = False The justification would be that: xdelta 1.1.3 in sid, has limitation to files smaller than 2Gb, and our tar file is 2.9Gb Suggestion B: =========== Another option would be to change "pristine-tar" to not use the line 545: my $ret=system("$xdelta_program delta -0 --pristine $recreatetarball $tarball $delta{delta}") but use instead: my $ret=system("$xdelta_program delta -9 --pristine $recreatetarball $tarball $delta{delta}") (or something along those lines) to trigger the use of compression, and to make it compare tar files in their compressed form, instead of their uncompressed one. This probably would have to be brought to the maintainers of pristine-tar... I'm probably missing other good alternatives. Will appreciate any guidance and advice on how to move forward, Many Thanks Luis
