bzr: ERROR: exceptions.KeyError: 'Source' when building recipe on launchpad

[Phil Frost]

This is very similar to ​ #1030822, except in that bug the Source field was missing from debian/control, while in my case it was present but I think not correctly parsed. Here's my failed build log:

https://launchpadlibrarian.net/131953502/buildlog.txt.gz

relevant traceback:

Traceback (most recent call last):
  File "/usr/lib/python2.5/site-packages/bzrlib/commands.py", line 946, in exception_to_return_code
    return the_callable(*args, **kwargs)
  File "/usr/lib/python2.5/site-packages/bzrlib/commands.py", line 1150, in run_bzr
    ret = run(*run_argv)
  File "/usr/lib/python2.5/site-packages/bzrlib/commands.py", line 699, in run_argv_aliases
    return self.run(**all_cmd_args)
  File "/usr/lib/python2.5/site-packages/bzrlib/commands.py", line 721, in run
    return self._operation.run_simple(*args, **kwargs)
  File "/usr/lib/python2.5/site-packages/bzrlib/cleanup.py", line 135, in run_simple
    self.cleanups, self.func, *args, **kwargs)
  File "/usr/lib/python2.5/site-packages/bzrlib/cleanup.py", line 165, in _do_with_cleanups
    result = func(*args, **kwargs)
  File "/usr/lib/python2.5/site-packages/bzrlib/plugins/builder/cmds.py", line 653, in run
    package = debian_source_package_name(control_path)
  File "/usr/lib/python2.5/site-packages/bzrlib/plugins/builder/cmds.py", line 499, in debian_source_package_name
    return control["Source"].encode("ascii")
  File "/var/lib/python-support/python2.5/debian_bundle/deb822.py", line 95, in __getitem__
    return self.__dict[key]
KeyError: 'Source'

the control file as it was for this failure:

http://bazaar.launchpad.net/~bitglue/gnuradio/precise-packaging/view/20/debian/control

and my workaround:

http://bazaar.launchpad.net/~bitglue/gnuradio/precise-packaging/revision/22

My local version of bzr-builder didn't have any issue parsing debian/control with the comments, and it's probably a safe assumption that the debian and ubuntu builders for released packages do not either, since I derived this packaging from those official sources. So, perhaps something specific to the launchpad environment, or the version of bzr-builder there?