version.changeset seems to be broken on postgresql native versioning

[ztane]

version.changeset sort of works on Operation.INSERT, but all subsequent versions have changeset {}

[ztane]

I guess this is because the triggers do not implement the validity strategy properly.

[ztane]

I changed the strategy globally to subquery and the changeset works better excepting the fact that in initial create operation, null columns are not listed (and I'd want them to be, as they also have the respective column_mod set to true)

[rogerio-geru]

I'm also having problems in changeset using native versioning, but my changeset for subsequent versions is not empty, it has all the same fields again, like the insert operation.

In [11]: [(x.operation_type, x.changeset) for x in f.versions.all()]
Out[11]: 
[(0,
  {'_active': [None, True],
   'cnpj': [None, u'123'],
   'created': [None, datetime.datetime(2019, 6, 13, 20, 39, 0, 212959)],
   'discriminator': [None, u'company_financialinstitution'],
   'extradata': [None, {}],
   'id': [None, 1],
   'name': [None, u'roger'],
   'real_account_type': [None, u'1'],
   'slug': [None, u'ok'],
   'state': [None, u'APPROVED'],
   'updated': [None, datetime.datetime(2019, 6, 13, 20, 39, 0, 208204)],
   'uuid': [None, u'961c7ede4a0a49bc87fabc7ed06daf09']}),
 (1,
  {'_active': [None, True],
   'cnpj': [None, u'123'],
   'created': [None, datetime.datetime(2019, 6, 13, 20, 39, 0, 212959)],
   'discriminator': [None, u'company_financialinstitution'],
   'extradata': [None, {}],
   'id': [None, 1],
   'name': [None, u'opa'],
   'real_account_type': [None, u'1'],
   'slug': [None, u'ok'],
   'state': [None, u'APPROVED'],
   'updated': [None, datetime.datetime(2019, 6, 13, 20, 39, 10, 212201)],
   'uuid': [None, u'961c7ede4a0a49bc87fabc7ed06daf09']})]

Note that only name and updated was actually changed.

[rogerio-geru]

I've tried the subquery strategy, it does work for the first change, but the second one got the changed field from the first change...

Out[16]: 
[(0,
  {'_active': [None, True],
   'cnpj': [None, u'123'],
   'created': [None, datetime.datetime(2019, 6, 13, 21, 24, 17, 215111)],
   'discriminator': [None, u'company_financialinstitution'],
   'extradata': [None, {}],
   'id': [None, 1],
   'name': [None, u'roger'],
   'real_account_type': [None, u'1'],
   'slug': [None, u'ok'],
   'state': [None, u'APPROVED'],
   'updated': [None, datetime.datetime(2019, 6, 13, 21, 24, 17, 211916)],
   'uuid': [None, u'976e6d29a2f04e95983043c77741e0e9']}),
 (1,
  {'name': [u'roger', u'opa'],
   'updated': [datetime.datetime(2019, 6, 13, 21, 24, 17, 211916),
    datetime.datetime(2019, 6, 13, 21, 24, 25, 221017)]}),
 (1,
  {'cnpj': [u'123', u'valid'],
   'name': [u'roger', u'opa'],
   'slug': [u'ok', u'humm'],
   'updated': [datetime.datetime(2019, 6, 13, 21, 24, 17, 211916),
    datetime.datetime(2019, 6, 13, 21, 26, 38, 227577)]})]

I've changed name and updated, then cnpj, slug and updated.

What could I do to fix this? Any help much appreciated.