Pulp

When using the export distributor with the "start_date" parameter, the distributor will fail with an exception if there are no rpms or errata associated with the repo since start_date.

For example:

pulp-admin rpm repo create --repo-id zoo --feed https://repos.fedorapeople.org/repos/pulp/pulp/demo_repos/zoo/
pulp-admin rpm repo sync run --repo-id zoo
# this works
pulp-admin rpm repo export run --repo-id zoo
# this fails
pulp-admin rpm repo export run --repo-id zoo --start-date <utc date after the time of the last sync>

Here is the stack:

Exception caught from plugin during publish for repo [zoo]
Traceback (most recent call last):
File "/usr/lib/python2.7/site-packages/pulp/server/managers/repo/publish.py", line 116, in _do_publish
  publish_report = publish_repo(transfer_repo, conduit, call_config)
File "/usr/lib/python2.7/site-packages/pulp/server/async/tasks.py", line 578, in wrap_f
  return f(*args, **kwargs)
File "/usr/lib/python2.7/site-packages/pulp_rpm/plugins/distributors/export_distributor/distributor.py", line 135, in publish_repo
  return self._publisher.publish()
File "/usr/lib/python2.7/site-packages/pulp/plugins/util/publish_step.py", line 557, in publish
  return self.process_lifecycle()
File "/usr/lib/python2.7/site-packages/pulp/plugins/util/publish_step.py", line 502, in process_lifecycle
  super(PluginStep, self).process_lifecycle()
File "/usr/lib/python2.7/site-packages/pulp/plugins/util/publish_step.py", line 126, in process_lifecycle
  step.process()
File "/usr/lib/python2.7/site-packages/pulp/plugins/util/publish_step.py", line 203, in process
  self._process_block()
File "/usr/lib/python2.7/site-packages/pulp/plugins/util/publish_step.py", line 245, in _process_block
  self.process_main()
File "/usr/lib/python2.7/site-packages/pulp/plugins/util/publish_step.py", line 890, in process_main
  copytree(self.source_dir, self.target_dir, symlinks=self.preserve_symlinks)
File "/usr/lib/python2.7/site-packages/pulp/server/util.py", line 215, in copytree
  names = os.listdir(src)
Error: [Errno 2] No such file or directory: '/var/cache/pulp/reserved_resource_worker-0@beav-2/a4069b22-9444-401e-bc9e-bd5c0433aeea/scratch'

It would be better if the task succeeded (with an appropriate message) and simply did not create an export ISO.