Fixed #33080 -- Preserved nullability of textual fields on Oracle.

Thanks Matt Hoskins for the report.

1 files changed, 21 insertions, 0 deletions

diff --git a/tests/schema/tests.py b/tests/schema/tests.py
index 7dfad1b5d6..9e23c4608e 100644
--- a/tests/schema/tests.py
+++ b/tests/schema/tests.py
@@ -863,6 +863,27 @@ class SchemaTests(TransactionTestCase):
         with self.assertRaises(IntegrityError):
             Note.objects.create(info=None)
 
+    @skipUnlessDBFeature('interprets_empty_strings_as_nulls')
+    def test_alter_textual_field_not_null_to_null(self):
+        """
+        Nullability for textual fields is preserved on databases that
+        interpret empty strings as NULLs.
+        """
+        with connection.schema_editor() as editor:
+            editor.create_model(Author)
+        columns = self.column_classes(Author)
+        # Field is nullable.
+        self.assertTrue(columns['uuid'][1][6])
+        # Change to NOT NULL.
+        old_field = Author._meta.get_field('uuid')
+        new_field = SlugField(null=False, blank=True)
+        new_field.set_attributes_from_name('uuid')
+        with connection.schema_editor() as editor:
+            editor.alter_field(Author, old_field, new_field, strict=True)
+        columns = self.column_classes(Author)
+        # Nullability is preserved.
+        self.assertTrue(columns['uuid'][1][6])
+
     def test_alter_numeric_field_keep_null_status(self):
         """
         Changing a field type shouldn't affect the not null status.