Package: dpkg-dev Version: 1.19.0.5 Severity: normal "dpkg-buildpackage -j" looks similar to "make -j", and therefore it happens frequently that people pass -j instead of -J to dpkg-buildpackage.
A variant of this problem is #905788, with "sbuild -j5" passing -j5 to dpkg-buildpackage (and sbuild not even supporting -J). In this specific case the software itself does actually support parallel building and uses "dh --parallel", but several dh_auto_build calls end up being run in parallel with -j. And build failures are not even the worst problem, we do have plenty of packages in the archive that successfully build a package with some contents missing when a part of the build fails. It saddens me when I think about how much time I have already wasted debugging problems that turned out to be caused by "dpkg-buildpackage -j", and I do not see any usecase where using -j would actually be a good idea. dpkg-buildpackage should abort immediately with an error message when -j gets passed.
