Import fails with "marked but not imported"

This essentially means the importer thinks there should be a tagged revision present on Launchpad but there isn't now; i.e. the branches on Launchpad have been changed.

The fix is to examine the situation and usually to judiciously remove importer marks from its sqlite db where appropriate.

Seems that the number of packages with this error are increasing:
http://package-import.ubuntu.com/status/b3259e51d1463ec492dc7c7f8c076621.html

This can occur when the import fails between marking them in the DB and finishing pushing the branches to LP. Mostly sporadic network/LP failures.

Guys, how do you develop? I'm trying to checkout ifupdown and it fails:

bzr branch lp:ubuntu/vivid/ifupdown
The authenticity of host 'bazaar.launchpad.net (91.189.95.84)' can't be established.
RSA key fingerprint is SHA256:dS2DmMhdbMsWaFP4HOF7A/ut73ozMR/gDL2Xxs01/7A.
Are you sure you want to continue connecting (yes/no)? yes
Warning: Permanently added 'bazaar.launchpad.net,91.189.95.84' (RSA) to the list of known hosts.
bzr: ERROR: Revision {<email address hidden>} not present in "Graph(StackedParentsProvider(bzrlib.repository._LazyListJoin(([CachingParentsProvider(None)], []))))".

http://package-import.ubuntu.com/status/ifupdown.html

bzr-based UDD is now deprecated. Try using "pull-lp-source" from the ubuntu-dev-tools package instead for non-VCS access to sources.

There is separate work on a git-based replacement, but it is not ready yet.