gistfile1.py

from django.db import models
import reversion
from reversion.models import Revision
from django.db import transaction
from django.db.models.signals import m2m_changed
 
class M2MRevisionManager(reversion.revisions.RevisionManager):
    def register(self, model=None, adapter_cls=reversion.VersionAdapter, **field_overrides):
        m2m_fields = model._meta.local_many_to_many
        for f in m2m_fields:
            m2m_changed.connect(self._m2m_changed_receiver, f.rel.through)
            pass
        
        super(M2MRevisionManager, self).register(
                model,
                adapter_cls,
                **field_overrides)
        
    def _m2m_changed_receiver(self, instance, **kwargs):
        if not kwargs['reverse']:
            self._post_save_receiver(instance, **kwargs)
    
 
reversion_patched = M2MRevisionManager('m2mrevisions')
class DAGNode(models.Model):
    parents = models.ManyToManyField('self', symmetrical=False, blank=True, related_name="children")
    
    def __unicode__(self):
        return unicode(self.id)
 
def print_revision_details(revisions):
    for r in revisions:
        print "Revision {0} has {1} versions".format(r.id, r.version_set.count())
        for v in r.version_set.all():
            print "\tVersion {0} for object {1} (type: {3}), serialized data: {2}".format(v.id, v.object_id, v.serialized_data, v.content_type)
 
def reversion_patched_test():
    reversion_patched.register(DAGNode)
    with transaction.atomic(), reversion.create_revision():
        parent = DAGNode(id = 200)
        parent.save()
    
    with transaction.atomic(), reversion.create_revision():
        child = DAGNode(id = 201)
        child.save()
    
    with transaction.atomic(), reversion.create_revision():
        child.parents.add(parent)
    
    reversion_patched.unregister(DAGNode)
    
    print_revision_details(list(Revision.objects.all())[-2:])
    
# Calling reversion_patched_test() with clean database returns:
# Revision 2 has 1 versions
#     Version 2 for object 201 (type: dag node), serialized data: [{"pk": 201, "model": "test_app.dagnode", "fields": {"parents": []}}]
# Revision 3 has 1 versions
#     Version 3 for object 201 (type: dag node), serialized data: [{"pk": 201, "model": "test_app.dagnode", "fields": {"parents": [200]}}]