I have job that first tries to check out the flufl.enum trunk code from Launchpad. You can see the url below. When I look at /var/lib/jenkins/job/taster/workspace, everything seems okay. In fact, there's a .bzr directory that's 0755 and jenkins:jenkins, plus it has the expected contents of the branch. I don't know why it's getting the permission denied, but this does seem to break my job.
Started by user anonymous
$ bzr branch https+urllib://code.launchpad.net/~barry/flufl.enum/trunk/ /var/lib/jenkins/jobs/taster/workspace
Branched 58 revision(s).
Getting local revision...
$ bzr revision-info -d /var/lib/jenkins/jobs/taster/workspace
info result: bzr revision-info -d /var/lib/jenkins/jobs/taster/workspace returned 0. Command output: "58 firstname.lastname@example.org
" stderr: "failed to open trace file: [Errno 13] Permission denied: '.bzr.log'
RevisionState revno:58 revid:email@example.com