Fixed #26034 -- Fixed incorrect index handling on PostgreSQL on Char/TextField with unique=True and db_index=True.

Thanks Simon Charette for review.

1 files changed, 60 insertions, 0 deletions

diff --git a/tests/schema/tests.py b/tests/schema/tests.py
index 7e17402f70..dfd0659d34 100644
--- a/tests/schema/tests.py
+++ b/tests/schema/tests.py
@@ -1757,3 +1757,63 @@ class SchemaTests(TransactionTestCase):
         with connection.schema_editor() as editor:
             editor.alter_field(Note, new_field, old_field, strict=True)
         self.assertEqual(self.get_constraints_for_column(Note, 'info'), [])
+
+    @unittest.skipUnless(connection.vendor == 'postgresql', "PostgreSQL specific")
+    def test_alter_field_add_unique_to_charfield_with_db_index(self):
+        # Create the table and verify initial indexes.
+        with connection.schema_editor() as editor:
+            editor.create_model(BookWithoutAuthor)
+        self.assertEqual(
+            self.get_constraints_for_column(BookWithoutAuthor, 'title'),
+            ['schema_book_d5d3db17', 'schema_book_title_2dfb2dff_like']
+        )
+        # Alter to add unique=True (should add 1 index)
+        old_field = BookWithoutAuthor._meta.get_field('title')
+        new_field = CharField(max_length=100, db_index=True, unique=True)
+        new_field.set_attributes_from_name('title')
+        with connection.schema_editor() as editor:
+            editor.alter_field(BookWithoutAuthor, old_field, new_field, strict=True)
+        self.assertEqual(
+            self.get_constraints_for_column(BookWithoutAuthor, 'title'),
+            ['schema_book_d5d3db17', 'schema_book_title_2dfb2dff_like', 'schema_book_title_2dfb2dff_uniq']
+        )
+        # Alter to remove unique=True (should drop unique index) # XXX: bug!
+        old_field = BookWithoutAuthor._meta.get_field('title')
+        new_field = CharField(max_length=100, db_index=True)
+        new_field.set_attributes_from_name('title')
+        with connection.schema_editor() as editor:
+            editor.alter_field(BookWithoutAuthor, old_field, new_field, strict=True)
+        self.assertEqual(
+            self.get_constraints_for_column(BookWithoutAuthor, 'title'),
+            ['schema_book_d5d3db17', 'schema_book_title_2dfb2dff_like', 'schema_book_title_2dfb2dff_uniq']
+        )
+
+    @unittest.skipUnless(connection.vendor == 'postgresql', "PostgreSQL specific")
+    def test_alter_field_add_db_index_to_charfield_with_unique(self):
+        # Create the table and verify initial indexes.
+        with connection.schema_editor() as editor:
+            editor.create_model(Tag)
+        self.assertEqual(
+            self.get_constraints_for_column(Tag, 'slug'),
+            ['schema_tag_slug_2c418ba3_like', 'schema_tag_slug_key']
+        )
+        # Alter to add db_index=True
+        old_field = Tag._meta.get_field('slug')
+        new_field = SlugField(db_index=True, unique=True)
+        new_field.set_attributes_from_name('slug')
+        with connection.schema_editor() as editor:
+            editor.alter_field(Tag, old_field, new_field, strict=True)
+        self.assertEqual(
+            self.get_constraints_for_column(Tag, 'slug'),
+            ['schema_tag_slug_2c418ba3_like', 'schema_tag_slug_key']
+        )
+        # Alter to remove db_index=True
+        old_field = Tag._meta.get_field('slug')
+        new_field = SlugField(unique=True)
+        new_field.set_attributes_from_name('slug')
+        with connection.schema_editor() as editor:
+            editor.alter_field(Tag, old_field, new_field, strict=True)
+        self.assertEqual(
+            self.get_constraints_for_column(Tag, 'slug'),
+            ['schema_tag_slug_2c418ba3_like', 'schema_tag_slug_key']
+        )