diff options
| -rw-r--r-- | django/core/management/commands/dumpdata.py | 2 | ||||
| -rw-r--r-- | django/core/serializers/__init__.py | 24 | ||||
| -rw-r--r-- | tests/fixtures/fixtures/circular_reference_natural_key.json | 16 | ||||
| -rw-r--r-- | tests/fixtures/models.py | 21 | ||||
| -rw-r--r-- | tests/fixtures/tests.py | 20 |
5 files changed, 70 insertions, 13 deletions
diff --git a/django/core/management/commands/dumpdata.py b/django/core/management/commands/dumpdata.py index 2968f74805..247b0f20fd 100644 --- a/django/core/management/commands/dumpdata.py +++ b/django/core/management/commands/dumpdata.py @@ -144,7 +144,7 @@ class Command(BaseCommand): Collate the objects to be serialized. If count_only is True, just count the number of objects to be serialized. """ - models = serializers.sort_dependencies(app_list.items()) + models = serializers.sort_dependencies(app_list.items(), allow_cycles=True) for model in models: if model in excluded_models: continue diff --git a/django/core/serializers/__init__.py b/django/core/serializers/__init__.py index d0e504ade3..5e16a7560f 100644 --- a/django/core/serializers/__init__.py +++ b/django/core/serializers/__init__.py @@ -156,12 +156,15 @@ def _load_serializers(): _serializers = serializers -def sort_dependencies(app_list): +def sort_dependencies(app_list, allow_cycles=False): """Sort a list of (app_config, models) pairs into a single list of models. The single list of models is sorted so that any model with a natural key is serialized before a normal model, and any model with a natural key dependency has it's dependencies serialized first. + + If allow_cycles is True, return the best-effort ordering that will respect + most of dependencies but ignore some of them to break the cycles. """ # Process the list of models, and get the list of dependencies model_dependencies = [] @@ -222,13 +225,20 @@ def sort_dependencies(app_list): else: skipped.append((model, deps)) if not changed: - raise RuntimeError( - "Can't resolve dependencies for %s in serialized app list." % - ', '.join( - model._meta.label - for model, deps in sorted(skipped, key=lambda obj: obj[0].__name__) + if allow_cycles: + # If cycles are allowed, add the last skipped model and ignore + # its dependencies. This could be improved by some graph + # analysis to ignore as few dependencies as possible. + model, _ = skipped.pop() + model_list.append(model) + else: + raise RuntimeError( + "Can't resolve dependencies for %s in serialized app list." + % ', '.join( + model._meta.label + for model, deps in sorted(skipped, key=lambda obj: obj[0].__name__) + ), ) - ) model_dependencies = skipped return model_list diff --git a/tests/fixtures/fixtures/circular_reference_natural_key.json b/tests/fixtures/fixtures/circular_reference_natural_key.json new file mode 100644 index 0000000000..d9dbe30aac --- /dev/null +++ b/tests/fixtures/fixtures/circular_reference_natural_key.json @@ -0,0 +1,16 @@ +[ + { + "model": "fixtures.circulara", + "fields": { + "key": "x", + "obj": ["y"] + } + }, + { + "model": "fixtures.circularb", + "fields": { + "key": "y", + "obj": ["x"] + } + } +] diff --git a/tests/fixtures/models.py b/tests/fixtures/models.py index db7d7fbd7a..ac64e7b82e 100644 --- a/tests/fixtures/models.py +++ b/tests/fixtures/models.py @@ -118,16 +118,17 @@ class PrimaryKeyUUIDModel(models.Model): id = models.UUIDField(primary_key=True, default=uuid.uuid4) +class NaturalKeyManager(models.Manager): + def get_by_natural_key(self, key): + return self.get(key=key) + + class NaturalKeyThing(models.Model): key = models.CharField(max_length=100, unique=True) other_thing = models.ForeignKey('NaturalKeyThing', on_delete=models.CASCADE, null=True) other_things = models.ManyToManyField('NaturalKeyThing', related_name='thing_m2m_set') - class Manager(models.Manager): - def get_by_natural_key(self, key): - return self.get(key=key) - - objects = Manager() + objects = NaturalKeyManager() def natural_key(self): return (self.key,) @@ -140,7 +141,17 @@ class CircularA(models.Model): key = models.CharField(max_length=3, unique=True) obj = models.ForeignKey('CircularB', models.SET_NULL, null=True) + objects = NaturalKeyManager() + + def natural_key(self): + return (self.key,) + class CircularB(models.Model): key = models.CharField(max_length=3, unique=True) obj = models.ForeignKey('CircularA', models.SET_NULL, null=True) + + objects = NaturalKeyManager() + + def natural_key(self): + return (self.key,) diff --git a/tests/fixtures/tests.py b/tests/fixtures/tests.py index 2ed17d57be..1e723a7b66 100644 --- a/tests/fixtures/tests.py +++ b/tests/fixtures/tests.py @@ -880,3 +880,23 @@ class CircularReferenceTests(DumpDataAssertMixin, TestCase): '{"model": "fixtures.circularb", "pk": 1, ' '"fields": {"key": "y", "obj": 1}}]', ) + + def test_circular_reference_natural_key(self): + management.call_command( + 'loaddata', + 'circular_reference_natural_key.json', + verbosity=0, + ) + obj_a = CircularA.objects.get() + obj_b = CircularB.objects.get() + self.assertEqual(obj_a.obj, obj_b) + self.assertEqual(obj_b.obj, obj_a) + self._dumpdata_assert( + ['fixtures'], + '[{"model": "fixtures.circulara", ' + '"fields": {"key": "x", "obj": ["y"]}}, ' + '{"model": "fixtures.circularb", ' + '"fields": {"key": "y", "obj": ["x"]}}]', + natural_primary_keys=True, + natural_foreign_keys=True, + ) |