Fixed #34060 -- Fixed migrations crash when adding check constraints with JSONField __exact lookup on Oracle.

django/db/backends/oracle/operations.py

@@ -347,9 +347,10 @@ END;
     def lookup_cast(self, lookup_type, internal_type=None):
         if lookup_type in ("iexact", "icontains", "istartswith", "iendswith"):
             return "UPPER(%s)"
-        if (
-            lookup_type != "isnull" and internal_type in ("BinaryField", "TextField")
-        ) or (lookup_type == "exact" and internal_type == "JSONField"):
+        if lookup_type != "isnull" and internal_type in (
+            "BinaryField",
+            "TextField",
+        ):
             return "DBMS_LOB.SUBSTR(%s)"
         return "%s"
 

django/db/backends/postgresql/features.py

@@ -106,6 +106,13 @@ class DatabaseFeatures(BaseDatabaseFeatures):
                     "test_group_by_nested_expression_with_params",
                 }
             )
+        if not is_psycopg3:
+            expected_failures.update(
+                {
+                    "constraints.tests.CheckConstraintTests."
+                    "test_validate_jsonfield_exact",
+                }
+            )
         return expected_failures
 
     @cached_property

django/db/models/fields/json.py

@@ -310,6 +310,11 @@ class JSONExact(lookups.Exact):
             rhs %= tuple(func)
         return rhs, rhs_params
 
+    def as_oracle(self, compiler, connection):
+        lhs, lhs_params = self.process_lhs(compiler, connection)
+        rhs, rhs_params = self.process_rhs(compiler, connection)
+        return f"JSON_EQUAL({lhs}, {rhs})", (*lhs_params, *rhs_params)
+
 
 class JSONIContains(CaseInsensitiveMixin, lookups.IContains):
     pass

tests/constraints/tests.py

@@ -365,6 +365,20 @@ class CheckConstraintTests(TestCase):
             constraint_with_pk.validate(ChildModel, ChildModel(id=1, age=1))
         constraint_with_pk.validate(ChildModel, ChildModel(pk=1, age=1), exclude={"pk"})
 
+    @skipUnlessDBFeature("supports_json_field")
+    def test_validate_jsonfield_exact(self):
+        data = {"release": "5.0.2", "version": "stable"}
+        json_exact_constraint = models.CheckConstraint(
+            check=models.Q(data__version="stable"),
+            name="only_stable_version",
+        )
+        json_exact_constraint.validate(JSONFieldModel, JSONFieldModel(data=data))
+
+        data = {"release": "5.0.2", "version": "not stable"}
+        msg = f"Constraint “{json_exact_constraint.name}” is violated."
+        with self.assertRaisesMessage(ValidationError, msg):
+            json_exact_constraint.validate(JSONFieldModel, JSONFieldModel(data=data))
+
 
 class UniqueConstraintTests(TestCase):
     @classmethod

tests/schema/tests.py

@@ -2803,6 +2803,40 @@ class SchemaTests(TransactionTestCase):
             DurationModel.objects.create(duration=datetime.timedelta(minutes=4))
         DurationModel.objects.create(duration=datetime.timedelta(minutes=10))
 
+    @skipUnlessDBFeature(
+        "supports_column_check_constraints",
+        "can_introspect_check_constraints",
+        "supports_json_field",
+    )
+    @isolate_apps("schema")
+    def test_check_constraint_exact_jsonfield(self):
+        class JSONConstraintModel(Model):
+            data = JSONField()
+
+            class Meta:
+                app_label = "schema"
+
+        with connection.schema_editor() as editor:
+            editor.create_model(JSONConstraintModel)
+        self.isolated_local_models = [JSONConstraintModel]
+        constraint_name = "check_only_stable_version"
+        constraint = CheckConstraint(
+            check=Q(data__version="stable"),
+            name=constraint_name,
+        )
+        JSONConstraintModel._meta.constraints = [constraint]
+        with connection.schema_editor() as editor:
+            editor.add_constraint(JSONConstraintModel, constraint)
+        constraints = self.get_constraints(JSONConstraintModel._meta.db_table)
+        self.assertIn(constraint_name, constraints)
+        with self.assertRaises(IntegrityError), atomic():
+            JSONConstraintModel.objects.create(
+                data={"release": "5.0.2dev", "version": "dev"}
+            )
+        JSONConstraintModel.objects.create(
+            data={"release": "5.0.3", "version": "stable"}
+        )
+
     @skipUnlessDBFeature(
         "supports_column_check_constraints", "can_introspect_check_constraints"
     )