subrepo: compare svn subrepo state to last committed revision A subversion project revisions are a subset of the repository revisions, you can ask subversion to update a working directory from one revision to another without changing anything. Unfortunately, Mercurial will think the subrepository has changed and will commit it again. To avoid useless commits, we compare the subrepository state to its actual "parent" revision. To ensure ascending compatibility with existing subrepositories which might reference fake revisions, we also keep comparing with the subrepo working directory revision. NOTE: not sure if this should go in stable or not.