DeserializationError: can't revert object with F() function

[NguyenMinhDung]

DeserializationError                      Traceback (most recent call last)
<ipython-input-20-775fb025c638> in <module>
      3 data = versions[1].serialized_data
      4 
----> 5 list(serializers.deserialize("json", data))

~/PycharmProjects/dicago/venv/lib/python3.8/site-packages/django/core/serializers/json.py in Deserializer(stream_or_string, **options)
     67     try:
     68         objects = json.loads(stream_or_string)
---> 69         yield from PythonDeserializer(objects, **options)
     70     except (GeneratorExit, DeserializationError):
     71         raise

~/PycharmProjects/dicago/venv/lib/python3.8/site-packages/django/core/serializers/python.py in Deserializer(object_list, using, ignorenonexistent, **options)
    143                     data[field.name] = field.to_python(field_value)
    144                 except Exception as e:
--> 145                     raise base.DeserializationError.WithData(e, d['model'], d.get('pk'), field_value)
    146 
    147         obj = base.build_instance(Model, data, using)

DeserializationError: ["'F(edits) + Value(1)' value must be an integer."]: (post:pk=1) field_value was 'F(edits) + Value(1)'.

I get the error when I try to revert to old version
Does anyone know the problem?

[etianen]

What do you mean by "object with F() function"?

…

On Tue, 8 Sep 2020 at 12:07, Windreams ***@***.***> wrote: DeserializationError Traceback (most recent call last) <ipython-input-20-775fb025c638> in <module> 3 data = versions[1].serialized_data 4 ----> 5 list(serializers.deserialize("json", data)) ~/PycharmProjects/dicago/venv/lib/python3.8/site-packages/django/core/serializers/json.py in Deserializer(stream_or_string, **options) 67 try: 68 objects = json.loads(stream_or_string) ---> 69 yield from PythonDeserializer(objects, **options) 70 except (GeneratorExit, DeserializationError): 71 raise ~/PycharmProjects/dicago/venv/lib/python3.8/site-packages/django/core/serializers/python.py in Deserializer(object_list, using, ignorenonexistent, **options) 143 data[field.name] = field.to_python(field_value) 144 except Exception as e: --> 145 raise base.DeserializationError.WithData(e, d['model'], d.get('pk'), field_value) 146 147 obj = base.build_instance(Model, data, using) DeserializationError: ["'F(edits) + Value(1)' value must be an integer."]: (post:pk=1) field_value was 'F(edits) + Value(1)'. I get the error when I try to revert to old version Does anyone know the problem? — You are receiving this because you are subscribed to this thread. Reply to this email directly, view it on GitHub <#848>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AABEKCDDLDV3OOUMNYOAP23SEYGADANCNFSM4Q72Q2QA> .

[NguyenMinhDung]

I use F(edits) + Value(1) to increase edits field by 1 when I save obj to database.
When reversion capture my obj, It contains F(edits) + Value(1) after that I revert the version I receive the error.

[etianen]

That's annoying. I had no idea it was even possible to do that. I've used F expressions on update() calls, but I didn't know it could be set on instances. As a workaround, you can use select_for_update() when you load the model. That allows you to increment the edits fields atomically without using an F expression.

…

On Tue, 8 Sep 2020 at 16:59, Windreams ***@***.***> wrote: I use F(edits) + Value(1) to increase edits field by 1 when I save obj to database. When reversion capture my obj, It contains F(edits) + Value(1) after that I revert the version I receive the error. — You are receiving this because you commented. Reply to this email directly, view it on GitHub <#848 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AABEKCDZLWCUEV2ZRPCOO43SEZIFJANCNFSM4Q72Q2QA> .

[dytechgithub]

I had the same issue using this, self.version = F("version") + 1.
Now if I use the below code, I am getting this error django.core.serializers.base.DeserializationError: ['“F(version) + Value(1)” value must be an integer.']

        with transaction.atomic(), reversion.create_revision():
            self.save()
            reversion.set_user(user)

but if I use this code, the revision is working fine, but I think this is a little inefficient,

       self.save()
       with transaction.atomic(), reversion.create_revision():
           self.refresh_from_db()
           self.save()
           reversion.set_user(user)