Ticket #25172: multi_db_checks.diff

django/db/models/fields/__init__.py

@@ -19 +19 @@
 # django.core.exceptions. It is retained here for backwards compatibility
 # purposes.
 from django.core.exceptions import FieldDoesNotExist  # NOQA
-from django.db import connection
+from django.db import connection, connections, router
 from django.db.models.lookups import (
     Lookup, RegisterLookupMixin, Transform, default_lookups,
 )
@@ -315 +315 @@
             return []
 
     def _check_backend_specific_checks(self, **kwargs):
-        return connection.validation.check_field(self, **kwargs)
+        app_label = self.model._meta.app_label
+        for db in connections:
+            if router.allow_migrate(db, app_label, model=self.model):
+                return connections[db].validation.check_field(self, **kwargs)
 
     def _check_deprecation_details(self):
         if self.system_check_removed_details is not None:

new file tests/check_framework/test_multi_db.py

@@ +1 @@
+from django.db import connections, models
+from django.test import TestCase, mock
+from django.test.utils import override_settings
+
+from .tests import IsolateModelsMixin
+
+
+class TestRouter(object):
+    """
+    Dummy router that would route to the 'other' database
+    if the model name starts with 'Other'.
+    """
+    def db_for_read(self, model, **hints):
+        return self._route(model)
+
+    def db_for_write(self, model, **hints):
+        return self._route(model)
+
+    def allow_relation(self, obj1, obj2, **hints):
+        return obj1._state.db == obj2._state.db
+
+    def allow_migrate(self, db, app_label, **hints):
+        model = hints.get('model')
+        return db == self._route(model)
+
+    def _route(self, model):
+        if model._meta.verbose_name.startswith('other'):
+            return 'other'
+
+        return 'default'
+
+
+@override_settings(DATABASE_ROUTERS=[TestRouter()])
+class TestMultiDBChecks(IsolateModelsMixin, TestCase):
+    multi_db = True
+
+    def test_checks_called_on_the_default_database(self):
+        class Model(models.Model):
+            field = models.CharField(max_length=100)
+
+        model = Model()
+        with mock.patch.object(connections['default'].validation, 'check_field') as mock_check_field:
+            model.check()
+            self.assertTrue(mock_check_field.called)
+
+    def test_checks_called_on_the_other_database(self):
+        class OtherModel(models.Model):
+            field = models.CharField(max_length=100)
+
+        model = OtherModel()
+        with mock.patch.object(connections['other'].validation, 'check_field') as mock_check_field:
+            model.check()
+            self.assertTrue(mock_check_field.called)

tests/invalid_models_tests/test_backend_specific.py

@@ -5 +5 @@
 
 from django.core.checks import Error
 from django.db import connection, models
+from django.test import mock
 
 from .base import IsolatedModelsTestCase
 
 
+def dummy_allow_migrate(db, app_label, **hints):
+    # Only allow_migrate on default so we can mock the check_field
+    # on the proper validation instance
+    return db == 'default'
+
+
 class BackendSpecificChecksTests(IsolatedModelsTestCase):
 
+    @mock.patch('django.db.models.fields.router.allow_migrate',
+                new=dummy_allow_migrate)
     def test_check_field(self):
         """ Test if backend specific checks are performed. """
 
         error = Error('an error', hint=None)
 
-        def mock(self, field, **kwargs):
+        def mock_check_field(self, field, **kwargs):
             return [error]
 
         class Model(models.Model):
@@ -27 +36 @@
         # Mock connection.validation.check_field method.
         v = connection.validation
         old_check_field = v.check_field
-        v.check_field = MethodType(mock, v)
+        v.check_field = MethodType(mock_check_field, v)
         try:
             errors = field.check()
         finally:

tests/postgres_tests/test_array.py

@@ -14 +14 @@
 from .models import (
     ArrayFieldSubclass, CharArrayModel, DateTimeArrayModel, IntegerArrayModel,
     NestedIntegerArrayModel, NullableIntegerArrayModel, OtherTypesArrayModel,
+    PostgreSQLModel,
 )
 
 try:
@@ -246 +247 @@
 class TestChecks(PostgreSQLTestCase):
 
     def test_field_checks(self):
-        field = ArrayField(models.CharField())
-        field.set_attributes_from_name('field')
-        errors = field.check()
+        class MyModel(PostgreSQLModel):
+            field = ArrayField(models.CharField())
+
+        model = MyModel()
+        errors = model.check()
         self.assertEqual(len(errors), 1)
         self.assertEqual(errors[0].id, 'postgres.E001')
 
     def test_invalid_base_fields(self):
-        field = ArrayField(models.ManyToManyField('postgres_tests.IntegerArrayModel'))
-        field.set_attributes_from_name('field')
-        errors = field.check()
+        class MyModel(PostgreSQLModel):
+            field = ArrayField(models.ManyToManyField('postgres_tests.IntegerArrayModel'))
+
+        model = MyModel()
+        errors = model.check()
         self.assertEqual(len(errors), 1)
         self.assertEqual(errors[0].id, 'postgres.E002')