[5.0.x] Fixed #35002 -- Made UniqueConstraints with fields respect nu…

…lls_distinct.

Regression in 595a2ab.

Backport of 54cb1a7 from main

django/db/backends/base/schema.py

@@ -111,7 +111,7 @@ class BaseDatabaseSchemaEditor:
 
     sql_create_unique = (
         "ALTER TABLE %(table)s ADD CONSTRAINT %(name)s "
-        "UNIQUE (%(columns)s)%(deferrable)s"
+        "UNIQUE%(nulls_distinct)s (%(columns)s)%(deferrable)s"
     )
     sql_delete_unique = sql_delete_constraint
 

tests/schema/tests.py

@@ -3474,7 +3474,7 @@ def test_func_unique_constraint_nondeterministic(self):
                 editor.add_constraint(Author, constraint)
 
     @skipUnlessDBFeature("supports_nulls_distinct_unique_constraints")
-    def test_unique_constraint_nulls_distinct(self):
+    def test_unique_constraint_index_nulls_distinct(self):
         with connection.schema_editor() as editor:
             editor.create_model(Author)
         nulls_distinct = UniqueConstraint(
@@ -3497,6 +3497,29 @@ def test_unique_constraint_nulls_distinct(self):
         self.assertNotIn(nulls_distinct.name, constraints)
         self.assertNotIn(nulls_not_distinct.name, constraints)
 
+    @skipUnlessDBFeature("supports_nulls_distinct_unique_constraints")
+    def test_unique_constraint_nulls_distinct(self):
+        with connection.schema_editor() as editor:
+            editor.create_model(Author)
+        constraint = UniqueConstraint(
+            fields=["height", "weight"], name="constraint", nulls_distinct=False
+        )
+        with connection.schema_editor() as editor:
+            editor.add_constraint(Author, constraint)
+        Author.objects.create(name="", height=None, weight=None)
+        Author.objects.create(name="", height=1, weight=None)
+        Author.objects.create(name="", height=None, weight=1)
+        with self.assertRaises(IntegrityError):
+            Author.objects.create(name="", height=None, weight=None)
+        with self.assertRaises(IntegrityError):
+            Author.objects.create(name="", height=1, weight=None)
+        with self.assertRaises(IntegrityError):
+            Author.objects.create(name="", height=None, weight=1)
+        with connection.schema_editor() as editor:
+            editor.remove_constraint(Author, constraint)
+        constraints = self.get_constraints(Author._meta.db_table)
+        self.assertNotIn(constraint.name, constraints)
+
     @skipIfDBFeature("supports_nulls_distinct_unique_constraints")
     def test_unique_constraint_nulls_distinct_unsupported(self):
         # UniqueConstraint is ignored on databases that don't support