Commit ceadc94f authored by Shai Berger's avatar Shai Berger
Browse files

Fixed #24307: Avoided redundant column nullability modifications on Oracle 

Thanks Joris Benschop for the report, and Tim Graham for the tests.
parent f7d34fe7

django/db/backends/base/schema.py

+5 −1
Original line number Diff line number Diff line
@@ -593,7 +593,11 @@ class BaseDatabaseSchemaEditor(object): 
                ))

        # Nullability change?

        if old_field.null != new_field.null:

            if new_field.null:

            if (self.connection.features.interprets_empty_strings_as_nulls and

                    new_field.get_internal_type() in ("CharField", "TextField")):

                # The field is nullable in the database anyway, leave it alone

                pass

            elif new_field.null:

                null_actions.append((

                    self.sql_alter_column_null % {

                        "column": self.quote_name(new_field.column),

tests/schema/tests.py

+32 −1
Original line number Diff line number Diff line 
import datetime

import itertools

import unittest

from copy import copy



from django.db import (

    DatabaseError, IntegrityError, OperationalError, connection,
@@ -411,7 +412,7 @@ class SchemaTests(TransactionTestCase): 
        # Ensure the field is right afterwards

        columns = self.column_classes(Author)

        self.assertEqual(columns['name'][0], "TextField")

        self.assertEqual(bool(columns['name'][1][6]), False)

        self.assertEqual(bool(columns['name'][1][6]), bool(connection.features.interprets_empty_strings_as_nulls))



    def test_alter_text_field(self):

        # Regression for "BLOB/TEXT column 'info' can't have a default value")
@@ -454,6 +455,36 @@ class SchemaTests(TransactionTestCase): 
        self.assertEqual(Author.objects.get(name='Not null author').height, 12)

        self.assertEqual(Author.objects.get(name='Null author').height, 42)



    def test_alter_charfield_to_null(self):

        """

        #24307 - Should skip an alter statement on databases with

        interprets_empty_strings_as_null when changing a CharField to null.

        """

        # Create the table

        with connection.schema_editor() as editor:

            editor.create_model(Author)

        # Change the CharField to null

        old_field = Author._meta.get_field('name')

        new_field = copy(old_field)

        new_field.null = True

        with connection.schema_editor() as editor:

            editor.alter_field(Author, old_field, new_field)



    def test_alter_textfield_to_null(self):

        """

        #24307 - Should skip an alter statement on databases with

        interprets_empty_strings_as_null when changing a TextField to null.

        """

        # Create the table

        with connection.schema_editor() as editor:

            editor.create_model(Note)

        # Change the TextField to null

        old_field = Note._meta.get_field('info')

        new_field = copy(old_field)

        new_field.null = True

        with connection.schema_editor() as editor:

            editor.alter_field(Note, old_field, new_field)



    @unittest.skipUnless(connection.features.supports_combined_alters, "No combined ALTER support")

    def test_alter_null_to_not_null_keeping_default(self):

        """