Optimized Model and QuerySet pickling version comparison.

django/db/models/base.py

@@ -4,6 +4,7 @@ import warnings
 from functools import partialmethod
 from itertools import chain
 
+import django
 from django.apps import apps
 from django.conf import settings
 from django.core import checks
@@ -36,7 +37,6 @@ from django.utils.encoding import force_str
 from django.utils.hashable import make_hashable
 from django.utils.text import capfirst, get_text_list
 from django.utils.translation import gettext_lazy as _
-from django.utils.version import get_version
 
 
 class Deferred:
@@ -538,7 +538,7 @@ class Model(metaclass=ModelBase):
 
     def __reduce__(self):
         data = self.__getstate__()
-        data[DJANGO_VERSION_PICKLE_KEY] = get_version()
+        data[DJANGO_VERSION_PICKLE_KEY] = django.__version__
         class_id = self._meta.app_label, self._meta.object_name
         return model_unpickle, (class_id,), data
 
@@ -547,21 +547,22 @@ class Model(metaclass=ModelBase):
         return self.__dict__
 
     def __setstate__(self, state):
-        msg = None
         pickled_version = state.get(DJANGO_VERSION_PICKLE_KEY)
         if pickled_version:
-            current_version = get_version()
-            if current_version != pickled_version:
-                msg = (
-                    "Pickled model instance's Django version %s does not match "
-                    "the current version %s." % (pickled_version, current_version)
+            if pickled_version != django.__version__:
+                warnings.warn(
+                    "Pickled model instance's Django version %s does not "
+                    "match the current version %s."
+                    % (pickled_version, django.__version__),
+                    RuntimeWarning,
+                    stacklevel=2,
                 )
         else:
-            msg = "Pickled model instance's Django version is not specified."
-
-        if msg:
-            warnings.warn(msg, RuntimeWarning, stacklevel=2)
-
+            warnings.warn(
+                "Pickled model instance's Django version is not specified.",
+                RuntimeWarning,
+                stacklevel=2,
+            )
         self.__dict__.update(state)
 
     def _get_pk_val(self, meta=None):

django/db/models/query.py

@@ -9,6 +9,7 @@ from collections import namedtuple
 from functools import lru_cache
 from itertools import chain
 
+import django
 from django.conf import settings
 from django.core import exceptions
 from django.db import (
@@ -25,7 +26,6 @@ from django.db.models.sql.constants import CURSOR, GET_ITERATOR_CHUNK_SIZE
 from django.db.models.utils import resolve_callables
 from django.utils import timezone
 from django.utils.functional import cached_property, partition
-from django.utils.version import get_version
 
 # The maximum number of results to fetch in a get() query.
 MAX_GET_RESULTS = 21
@@ -238,24 +238,25 @@ class QuerySet:
     def __getstate__(self):
         # Force the cache to be fully populated.
         self._fetch_all()
-        return {**self.__dict__, DJANGO_VERSION_PICKLE_KEY: get_version()}
+        return {**self.__dict__, DJANGO_VERSION_PICKLE_KEY: django.__version__}
 
     def __setstate__(self, state):
-        msg = None
         pickled_version = state.get(DJANGO_VERSION_PICKLE_KEY)
         if pickled_version:
-            current_version = get_version()
-            if current_version != pickled_version:
-                msg = (
+            if pickled_version != django.__version__:
+                warnings.warn(
                     "Pickled queryset instance's Django version %s does not "
-                    "match the current version %s." % (pickled_version, current_version)
+                    "match the current version %s."
+                    % (pickled_version, django.__version__),
+                    RuntimeWarning,
+                    stacklevel=2,
                 )
         else:
-            msg = "Pickled queryset instance's Django version is not specified."
-
-        if msg:
-            warnings.warn(msg, RuntimeWarning, stacklevel=2)
-
+            warnings.warn(
+                "Pickled queryset instance's Django version is not specified.",
+                RuntimeWarning,
+                stacklevel=2,
+            )
         self.__dict__.update(state)
 
     def __repr__(self):

tests/model_regress/test_pickle.py

@@ -1,8 +1,8 @@
 import pickle
 
+import django
 from django.db import DJANGO_VERSION_PICKLE_KEY, models
 from django.test import SimpleTestCase
-from django.utils.version import get_version
 
 
 class ModelPickleTests(SimpleTestCase):
@@ -40,7 +40,10 @@ class ModelPickleTests(SimpleTestCase):
                 return reduce_list
 
         p = DifferentDjangoVersion(title="FooBar")
-        msg = "Pickled model instance's Django version 1.0 does not match the current version %s." % get_version()
+        msg = (
+            "Pickled model instance's Django version 1.0 does not match the "
+            "current version %s." % django.__version__
+        )
         with self.assertRaisesMessage(RuntimeWarning, msg):
             pickle.loads(pickle.dumps(p))
 

tests/queryset_pickle/tests.py

@@ -1,9 +1,9 @@
 import datetime
 import pickle
 
+import django
 from django.db import models
 from django.test import TestCase
-from django.utils.version import get_version
 
 from .models import Container, Event, Group, Happening, M2MModel, MyEvent
 
@@ -234,7 +234,10 @@ class PickleabilityTestCase(TestCase):
         unpickled with a different Django version than the current
         """
         qs = Group.previous_django_version_objects.all()
-        msg = "Pickled queryset instance's Django version 1.0 does not match the current version %s." % get_version()
+        msg = (
+            "Pickled queryset instance's Django version 1.0 does not match "
+            "the current version %s." % django.__version__
+        )
         with self.assertRaisesMessage(RuntimeWarning, msg):
             pickle.loads(pickle.dumps(qs))