"git ubuntu build" produces false "error" output when no quilt patches are present

[Robie Basak]

11/08/2018 13:03:51 - ERROR:Command exited 2: quilt --quiltrc - push -a
11/08/2018 13:03:51 - ERROR:stdout:
11/08/2018 13:03:51 - ERROR:stderr: No series file found

This is innocuous and should be suppressed.

[Bryce Harrington (bryce)]

Still reproducible on current git-ubuntu:

02/20/2020 16:44:10 - DEBUG:Executing: git worktree prune
02/20/2020 16:44:10 - DEBUG:Executing: tar -x --strip-components=1 -f /tmp/tmp6dwf986j/rsync_3.1.2.orig.tar.gz
02/20/2020 16:44:10 - DEBUG:Unable to find a series file in <_pygit2.Commit object at 0x7fd0436eef90>
02/20/2020 16:44:10 - DEBUG:Executing: quilt --quiltrc - push -a
02/20/2020 16:44:10 - DEBUG:Executing: git worktree add --detach --force /tmp/tmpje_4hpxj 9d30db948107e5372c107b5b2657dd37df932db1
02/20/2020 16:44:10 - DEBUG:Unable to find a series file in <_pygit2.Commit object at 0x7fd0436eefd0>
02/20/2020 16:44:10 - DEBUG:Executing: quilt --quiltrc - push -a
02/20/2020 16:44:10 - ERROR:Command exited 2: quilt --quiltrc - push -a
02/20/2020 16:44:10 - ERROR:stdout:
02/20/2020 16:44:10 - ERROR:stderr: No series file found

02/20/2020 16:44:10 - DEBUG:Executing: git worktree prune

The call to determine_quilt_series_path() notices that there is no series file, but instead of returning None or throwing an exception, it is returning a default value ('debian/patches/series'), which quilt_env*() sets in the ENV.

GitUbuntuRepository.is_patches_applied() calls run_quilt() to check if patches are applied and if not has some logic to detect whether there are no patches to apply, or there's an extraneous .pc, or a real error has occurred. It's this run_quilt() call that causes the error messages. ("No series file found" comes from quilt itself.)

One possible way to correct this would be to modify determine_quilt_series_path() to return an error indicator of some sort if it did not find the series file. Then we can call this routine directly from GitUbuntuRepository.is_patches_applied() and know immediately when there are no patches and handle accordingly. quilt_env() would then apply the default 'debian/patches/series' when creating the env. The only other user of determine_quilt_series_path() is its test case, which would need adjusted as well.

A more brute force option may be to have run_quilt() capture the stderr and filter out the 'No series file found' error message. This feels hacky to me though.