Where does self.message get set on the Revision object?

[John Szakmeister]

I'm trying to debug a problem that I'm seeing while using 'bzr qlog'
on a repository.  When using it in conjunction with bzr-svn, and
running 'bzr qlog' against a Subversion repository, it back traces
with the error originating from Revision.get_summary().  In
particular, self.message is set to None.  However, I don't see where
it's ever set to begin with.  How does that member even appear on that
object?  Are there others that are expected to be there?  At the very
least, it looks like inventory_sha1, timestamp, message, timezone, and
committer need to be there... but that isn't mentioned anywhere in the
docs for Revision (it looks like that information is passed in via the
**args parameter to __init__() or set directly after the fact).

Is it acceptable that Revision.message is None?  FWIW, 'bzr log' shows
"(no message)" on the same revision that kills qlog, so it appears
that the command line tool can at least handle the fact that the
message is None (although it doesn't appear call get_summary() by
default, so it doesn't trigger that code path).  It would probably be
a good idea to document what attributes need to get added, and their
constraints (if any).

I'm also asking so I know where to submit a patch... either bzrlib or
bzr-svn. :-)

Thanks!

-John