Refs #34534 -- Reduced constraint operations with Meta.constraints when optimizing migrations.

3 files changed, 115 insertions, 9 deletions

diff --git a/django/db/migrations/operations/models.py b/django/db/migrations/operations/models.py
index 38c68f3ff3..34b14107a7 100644
--- a/django/db/migrations/operations/models.py
+++ b/django/db/migrations/operations/models.py
@@ -342,6 +342,40 @@ class CreateModel(ModelOperation):
                         managers=self.managers,
                     ),
                 ]
+            elif isinstance(operation, AddConstraint):
+                return [
+                    CreateModel(
+                        self.name,
+                        fields=self.fields,
+                        options={
+                            **self.options,
+                            "constraints": [
+                                *self.options.get("constraints", []),
+                                operation.constraint,
+                            ],
+                        },
+                        bases=self.bases,
+                        managers=self.managers,
+                    ),
+                ]
+            elif isinstance(operation, RemoveConstraint):
+                options_constraints = [
+                    constraint
+                    for constraint in self.options.get("constraints", [])
+                    if constraint.name != operation.name
+                ]
+                return [
+                    CreateModel(
+                        self.name,
+                        fields=self.fields,
+                        options={
+                            **self.options,
+                            "constraints": options_constraints,
+                        },
+                        bases=self.bases,
+                        managers=self.managers,
+                    ),
+                ]
         return super().reduce(operation, app_label)
 
 
diff --git a/tests/migrations/test_autodetector.py b/tests/migrations/test_autodetector.py
index 340805b259..d36b72907d 100644
--- a/tests/migrations/test_autodetector.py
+++ b/tests/migrations/test_autodetector.py
@@ -2762,21 +2762,23 @@ class AutodetectorTests(BaseAutodetectorTests):
             },
         )
         changes = self.get_changes([], [author])
-        added_constraint = models.CheckConstraint(
+        constraint = models.CheckConstraint(
             check=models.Q(name__contains="Bob"), name="name_contains_bob"
         )
         # Right number of migrations?
         self.assertEqual(len(changes["otherapp"]), 1)
         # Right number of actions?
         migration = changes["otherapp"][0]
-        self.assertEqual(len(migration.operations), 2)
+        self.assertEqual(len(migration.operations), 1)
         # Right actions order?
-        self.assertOperationTypes(
-            changes, "otherapp", 0, ["CreateModel", "AddConstraint"]
-        )
-        self.assertOperationAttributes(changes, "otherapp", 0, 0, name="Author")
+        self.assertOperationTypes(changes, "otherapp", 0, ["CreateModel"])
         self.assertOperationAttributes(
-            changes, "otherapp", 0, 1, model_name="author", constraint=added_constraint
+            changes,
+            "otherapp",
+            0,
+            0,
+            name="Author",
+            options={"constraints": [constraint]},
         )
 
     def test_add_constraints(self):
@@ -4177,7 +4179,7 @@ class AutodetectorTests(BaseAutodetectorTests):
             changes,
             "testapp",
             0,
-            ["CreateModel", "AddConstraint"],
+            ["CreateModel"],
         )
         self.assertOperationAttributes(
             changes,
@@ -4185,7 +4187,14 @@ class AutodetectorTests(BaseAutodetectorTests):
             0,
             0,
             name="Author",
-            options={"order_with_respect_to": "book"},
+            options={
+                "order_with_respect_to": "book",
+                "constraints": [
+                    models.CheckConstraint(
+                        check=models.Q(_order__gt=1), name="book_order_gt_1"
+                    )
+                ],
+            },
         )
 
     def test_add_model_order_with_respect_to_index(self):
diff --git a/tests/migrations/test_optimizer.py b/tests/migrations/test_optimizer.py
index ece6580ad8..5c1fe3020e 100644
--- a/tests/migrations/test_optimizer.py
+++ b/tests/migrations/test_optimizer.py
@@ -1326,3 +1326,66 @@ class OptimizerTests(SimpleTestCase):
                 ),
             ],
         )
+
+    def test_create_model_add_constraint(self):
+        gt_constraint = models.CheckConstraint(
+            check=models.Q(weight__gt=0), name="pony_weight_gt_0"
+        )
+        self.assertOptimizesTo(
+            [
+                migrations.CreateModel(
+                    name="Pony",
+                    fields=[
+                        ("weight", models.IntegerField()),
+                    ],
+                ),
+                migrations.AddConstraint("Pony", gt_constraint),
+            ],
+            [
+                migrations.CreateModel(
+                    name="Pony",
+                    fields=[
+                        ("weight", models.IntegerField()),
+                    ],
+                    options={"constraints": [gt_constraint]},
+                ),
+            ],
+        )
+
+    def test_create_model_remove_constraint(self):
+        self.assertOptimizesTo(
+            [
+                migrations.CreateModel(
+                    name="Pony",
+                    fields=[
+                        ("weight", models.IntegerField()),
+                    ],
+                    options={
+                        "constraints": [
+                            models.CheckConstraint(
+                                check=models.Q(weight__gt=0), name="pony_weight_gt_0"
+                            ),
+                            models.UniqueConstraint(
+                                "weight", name="pony_weight_unique"
+                            ),
+                        ],
+                    },
+                ),
+                migrations.RemoveConstraint("Pony", "pony_weight_gt_0"),
+            ],
+            [
+                migrations.CreateModel(
+                    name="Pony",
+                    fields=[
+                        ("weight", models.IntegerField()),
+                    ],
+                    options={
+                        "constraints": [
+                            models.UniqueConstraint(
+                                "weight", name="pony_weight_unique"
+                            ),
+                        ]
+                    },
+                ),
+            ],
+        )