[1.9.x] Fixed #25412 -- Fixed missing PostgreSQL index on Char/TextField when using AlterField.

Thanks to Emanuele Palazzetti for the help.

Backport of 3a36c8079544c83dcdea4e52181efcd2d1e86b9c from master

1 files changed, 68 insertions, 0 deletions

diff --git a/tests/schema/tests.py b/tests/schema/tests.py
index eff310dccb..b8bd883d9e 100644
--- a/tests/schema/tests.py
+++ b/tests/schema/tests.py
@@ -1707,3 +1707,71 @@ class SchemaTests(TransactionTestCase):
         new_field.set_attributes_from_name("info")
         with connection.schema_editor() as editor:
             editor.add_field(Author, new_field)
+
+    @unittest.skipUnless(connection.vendor == 'postgresql', "PostgreSQL specific")
+    def test_alter_field_add_index_to_charfield(self):
+        # Create the table
+        with connection.schema_editor() as editor:
+            editor.create_model(Author)
+        # Ensure the table is there and has no index
+        self.assertNotIn('name', self.get_indexes(Author._meta.db_table))
+        # Alter to add the index
+        old_field = Author._meta.get_field('name')
+        new_field = CharField(max_length=255, db_index=True)
+        new_field.set_attributes_from_name('name')
+        with connection.schema_editor() as editor:
+            editor.alter_field(Author, old_field, new_field, strict=True)
+        # Check that all the constraints are there
+        constraints = self.get_constraints(Author._meta.db_table)
+        name_indexes = []
+        for name, details in constraints.items():
+            if details['columns'] == ['name']:
+                name_indexes.append(name)
+        self.assertEqual(2, len(name_indexes), 'Indexes are missing for name column')
+        # Check that one of the indexes ends with `_like`
+        like_index = [x for x in name_indexes if x.endswith('_like')]
+        self.assertEqual(1, len(like_index), 'Index with the operator class is missing for the name column')
+        # Remove the index
+        with connection.schema_editor() as editor:
+            editor.alter_field(Author, new_field, old_field, strict=True)
+        # Ensure the name constraints where dropped
+        constraints = self.get_constraints(Author._meta.db_table)
+        name_indexes = []
+        for details in constraints.values():
+            if details['columns'] == ['name']:
+                name_indexes.append(details)
+        self.assertEqual(0, len(name_indexes), 'Indexes were not dropped for the name column')
+
+    @unittest.skipUnless(connection.vendor == 'postgresql', "PostgreSQL specific")
+    def test_alter_field_add_index_to_textfield(self):
+        # Create the table
+        with connection.schema_editor() as editor:
+            editor.create_model(Note)
+        # Ensure the table is there and has no index
+        self.assertNotIn('info', self.get_indexes(Note._meta.db_table))
+        # Alter to add the index
+        old_field = Note._meta.get_field('info')
+        new_field = TextField(db_index=True)
+        new_field.set_attributes_from_name('info')
+        with connection.schema_editor() as editor:
+            editor.alter_field(Note, old_field, new_field, strict=True)
+        # Check that all the constraints are there
+        constraints = self.get_constraints(Note._meta.db_table)
+        info_indexes = []
+        for name, details in constraints.items():
+            if details['columns'] == ['info']:
+                info_indexes.append(name)
+        self.assertEqual(2, len(info_indexes), 'Indexes are missing for info column')
+        # Check that one of the indexes ends with `_like`
+        like_index = [x for x in info_indexes if x.endswith('_like')]
+        self.assertEqual(1, len(like_index), 'Index with the operator class is missing for the info column')
+        # Remove the index
+        with connection.schema_editor() as editor:
+            editor.alter_field(Note, new_field, old_field, strict=True)
+        # Ensure the info constraints where dropped
+        constraints = self.get_constraints(Note._meta.db_table)
+        info_indexes = []
+        for details in constraints.values():
+            if details['columns'] == ['info']:
+                info_indexes.append(details)
+        self.assertEqual(0, len(info_indexes), 'Indexes were not dropped for the info column')