Comment 8 for bug 336749

This is triggered by the fact that bzr-svn uses VersionedFiles.add_lines() while in fact it should be using VersionedFiles.add_lines_with_ghosts(), since the left hand side parent may be missing (if merged in from a ghost). Bazaar is using that (missing) lhs text as delta parent and errors out when trying to retrieve it. As a workaround, you can just specify None for the text parents in add_lines(), and that will fix this bug but will also break storage of the text revision graph.

Bazaar needs to add VersionedFiles.add_lines_with_ghosts() and bzr-svn needs to start using it.