severity 937009 serious thanks mercurial can no longer be built in testing because of a build-dependency on python-docutils which has been removed.
This is fixed in unstable, but mercurial is blocked from migrating to testing because it declares a conflicts on mercurial-crecord (<= 0.20151121-2) I think the <= should be changed to << because conflicting with a transitional dummy package does not make sense, but I am not in any way an expert on mercurial.