Fixed #25005 - Made DateTime and DateTimeField with auto_now/auto_now_add use effective default

django/db/backends/base/schema.py

@@ -1,8 +1,9 @@
+import datetime
 import hashlib
 
 from django.db.backends.utils import truncate_name
 from django.db.transaction import atomic
-from django.utils import six
+from django.utils import six, timezone
 from django.utils.encoding import force_bytes
 from django.utils.log import getLogger
 
@@ -201,6 +202,13 @@ def effective_default(self, field):
                 default = six.binary_type()
             else:
                 default = six.text_type()
+        elif getattr(field, 'auto_now', False) or getattr(field, 'auto_now_add', False):
+            default = timezone.now()  # default for DateTimeField
+            internal_type = field.get_internal_type()
+            if internal_type == 'DateField':
+                default = default.date()
+            elif internal_type == 'TimeField':
+                default = default.time()
         else:
             default = None
         # If it's a callable, call it

django/db/migrations/autodetector.py

@@ -788,7 +788,11 @@ def _generate_added_field(self, app_label, model_name, field_name):
         preserve_default = True
         if (not field.null and not field.has_default() and
                 not isinstance(field, models.ManyToManyField) and
-                not (field.blank and field.empty_strings_allowed)):
+                not (field.blank and field.empty_strings_allowed) and
+                not (
+                    isinstance(field, (models.DateField, models.DateTimeField, models.TimeField)) and
+                    (field.auto_now or field.auto_now_add)
+                )):
             field = field.clone()
             field.default = self.questioner.ask_not_null_addition(field_name, model_name)
             preserve_default = False

tests/migrations/test_autodetector.py

@@ -47,6 +47,18 @@ class AutodetectorTests(TestCase):
         ("id", models.AutoField(primary_key=True)),
         ("name", models.CharField(max_length=200, default='Ada Lovelace')),
     ])
+    author_dates_of_birth_auto_now = ModelState("testapp", "Author", [
+        ("id", models.AutoField(primary_key=True)),
+        ("date_of_birth", models.DateField(auto_now=True)),
+        ("date_time_of_birth", models.DateTimeField(auto_now=True)),
+        ("time_of_birth", models.TimeField(auto_now=True)),
+    ])
+    author_dates_of_birth_auto_now_add = ModelState("testapp", "Author", [
+        ("id", models.AutoField(primary_key=True)),
+        ("date_of_birth", models.DateField(auto_now_add=True)),
+        ("date_time_of_birth", models.DateTimeField(auto_now_add=True)),
+        ("time_of_birth", models.TimeField(auto_now_add=True)),
+    ])
     author_name_deconstructable_1 = ModelState("testapp", "Author", [
         ("id", models.AutoField(primary_key=True)),
         ("name", models.CharField(max_length=200, default=DeconstructableObject())),
@@ -522,6 +534,36 @@ def test_add_field(self):
         self.assertOperationTypes(changes, 'testapp', 0, ["AddField"])
         self.assertOperationAttributes(changes, "testapp", 0, 0, name="name")
 
+    @mock.patch('django.db.migrations.questioner.MigrationQuestioner.ask_not_null_addition',
+                side_effect=Exception("Should not have prompted for not null addition"))
+    def test_add_date_fields_with_auto_now_not_asking_for_default(self, mocked_ask_method):
+        # Make state
+        before = self.make_project_state([self.author_empty])
+        after = self.make_project_state([self.author_dates_of_birth_auto_now])
+        autodetector = MigrationAutodetector(before, after)
+        changes = autodetector._detect_changes()
+        # Right number/type of migrations?
+        self.assertNumberMigrations(changes, 'testapp', 1)
+        self.assertOperationTypes(changes, 'testapp', 0, ["AddField", "AddField", "AddField"])
+        self.assertOperationFieldAttributes(changes, "testapp", 0, 0, auto_now=True)
+        self.assertOperationFieldAttributes(changes, "testapp", 0, 1, auto_now=True)
+        self.assertOperationFieldAttributes(changes, "testapp", 0, 2, auto_now=True)
+
+    @mock.patch('django.db.migrations.questioner.MigrationQuestioner.ask_not_null_addition',
+                side_effect=Exception("Should not have prompted for not null addition"))
+    def test_add_date_fields_with_auto_now_add_not_asking_for_default(self, mocked_ask_method):
+        # Make state
+        before = self.make_project_state([self.author_empty])
+        after = self.make_project_state([self.author_dates_of_birth_auto_now_add])
+        autodetector = MigrationAutodetector(before, after)
+        changes = autodetector._detect_changes()
+        # Right number/type of migrations?
+        self.assertNumberMigrations(changes, 'testapp', 1)
+        self.assertOperationTypes(changes, 'testapp', 0, ["AddField", "AddField", "AddField"])
+        self.assertOperationFieldAttributes(changes, "testapp", 0, 0, auto_now_add=True)
+        self.assertOperationFieldAttributes(changes, "testapp", 0, 1, auto_now_add=True)
+        self.assertOperationFieldAttributes(changes, "testapp", 0, 2, auto_now_add=True)
+
     def test_remove_field(self):
         """Tests autodetection of removed fields."""
         # Make state

tests/schema/tests.py

@@ -3,13 +3,16 @@
 import unittest
 from copy import copy
 
+import mock
+
 from django.db import (
     DatabaseError, IntegrityError, OperationalError, connection,
 )
 from django.db.models import Model
 from django.db.models.fields import (
     AutoField, BigIntegerField, BinaryField, BooleanField, CharField,
-    DateTimeField, IntegerField, PositiveIntegerField, SlugField, TextField,
+    DateField, DateTimeField, IntegerField, PositiveIntegerField, SlugField,
+    TextField, TimeField,
 )
 from django.db.models.fields.related import (
     ForeignKey, ManyToManyField, OneToOneField,
@@ -1535,3 +1538,81 @@ def test_add_field_use_effective_default(self):
             cursor.execute("SELECT surname FROM schema_author;")
             item = cursor.fetchall()[0]
             self.assertEqual(item[0], None if connection.features.interprets_empty_strings_as_nulls else '')
+
+    @mock.patch('django.db.backends.base.schema.timezone')
+    def test_add_datefield_and_datetimefield_use_effective_default(self, mocked_tz):
+        """
+        #25005 - effective_default() should be used for DateField,
+        DateTimeField and TimeField if auto_now or auto_add_now is set.
+        """
+        now = datetime.datetime(month=1, day=1, year=2000, hour=1, minute=1)
+        mocked_tz.now = mock.MagicMock(return_value=now)
+        # Create the table
+        with connection.schema_editor() as editor:
+            editor.create_model(Author)
+        # Ensure there's no surname field
+        columns = self.column_classes(Author)
+        self.assertNotIn("date_of_birth_auto_now", columns)
+        self.assertNotIn("date_of_birth_auto_now_add", columns)
+        self.assertNotIn("date_time_of_birth_auto_now", columns)
+        self.assertNotIn("date_time_of_birth_auto_now_add", columns)
+        self.assertNotIn("time_of_birth_auto_now", columns)
+        self.assertNotIn("time_of_birth_auto_now_add", columns)
+        # Create a row
+        Author.objects.create(name='Anonymous1')
+        # Add new date and datetime fields to ensure default will be
+        # used from effective_default
+        date_of_birth_auto_now = DateField(auto_now=True)
+        date_of_birth_auto_now.set_attributes_from_name('date_of_birth_auto_now')
+
+        date_of_birth_auto_now_add = DateField(auto_now_add=True)
+        date_of_birth_auto_now_add.set_attributes_from_name('date_of_birth_auto_now_add')
+
+        date_time_of_birth_auto_now = DateTimeField(auto_now=True)
+        date_time_of_birth_auto_now.set_attributes_from_name('date_time_of_birth_auto_now')
+
+        date_time_of_birth_auto_now_add = DateTimeField(auto_now_add=True)
+        date_time_of_birth_auto_now_add.set_attributes_from_name('date_time_of_birth_auto_now_add')
+
+        time_of_birth_auto_now = TimeField(auto_now=True)
+        time_of_birth_auto_now.set_attributes_from_name('time_of_birth_auto_now')
+
+        time_of_birth_auto_now_add = TimeField(auto_now_add=True)
+        time_of_birth_auto_now_add.set_attributes_from_name('time_of_birth_auto_now_add')
+
+        # Ensure fields was added with the right defaults
+        with connection.schema_editor() as editor:
+            editor.add_field(Author, date_of_birth_auto_now)
+        with connection.cursor() as cursor:
+            cursor.execute("SELECT date_of_birth_auto_now FROM schema_author;")
+            self.assertEqual(cursor.fetchall()[0][0], now.date())
+
+        with connection.schema_editor() as editor:
+            editor.add_field(Author, date_of_birth_auto_now_add)
+        with connection.cursor() as cursor:
+            cursor.execute("SELECT date_of_birth_auto_now_add FROM schema_author;")
+            self.assertEqual(cursor.fetchall()[0][0], now.date())
+
+        with connection.schema_editor() as editor:
+            editor.add_field(Author, date_time_of_birth_auto_now)
+        with connection.cursor() as cursor:
+            cursor.execute("SELECT date_time_of_birth_auto_now FROM schema_author;")
+            self.assertEqual(cursor.fetchall()[0][0], now)
+
+        with connection.schema_editor() as editor:
+            editor.add_field(Author, date_time_of_birth_auto_now_add)
+        with connection.cursor() as cursor:
+            cursor.execute("SELECT date_time_of_birth_auto_now_add FROM schema_author;")
+            self.assertEqual(cursor.fetchall()[0][0], now)
+
+        with connection.schema_editor() as editor:
+            editor.add_field(Author, time_of_birth_auto_now)
+        with connection.cursor() as cursor:
+            cursor.execute("SELECT time_of_birth_auto_now FROM schema_author;")
+            self.assertEqual(cursor.fetchall()[0][0], now.time())
+
+        with connection.schema_editor() as editor:
+            editor.add_field(Author, time_of_birth_auto_now_add)
+        with connection.cursor() as cursor:
+            cursor.execute("SELECT time_of_birth_auto_now_add FROM schema_author;")
+            self.assertEqual(cursor.fetchall()[0][0], now.time())