#35839: GeneratedField with db_comment causes syntax error
-------------------------------+------------------------------------
Reporter: Jason Christa | Owner: (none)
Type: Bug | Status: new
Component: Migrations | Version: 5.0
Severity: Normal | Resolution:
Keywords: | Triage Stage: Accepted
Has patch: 0 | Needs documentation: 0
Needs tests: 0 | Patch needs improvement: 0
Easy pickings: 0 | UI/UX: 0
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Changes (by Simon Charette):
* component: Database layer (models, ORM) => Migrations
* stage: Unreviewed => Accepted
Comment:
Reproduced with the following test
{{{#!diff
diff --git a/tests/schema/tests.py b/tests/schema/tests.py
index 33a4bc527b..1dbbd5fe02 100644
--- a/tests/schema/tests.py
+++ b/tests/schema/tests.py
@@ -4861,6 +4861,24 @@ def test_add_db_comment_charfield(self):
comment,
)
+ @skipUnlessDBFeature("supports_comments")
+ def test_add_db_comment_generated_field(self):
+ comment = "Custom comment"
+ field = GeneratedField(
+ expression=Value(1),
+ db_persist=True,
+ output_field=IntegerField(),
+ db_comment=comment,
+ )
+ field.set_attributes_from_name("volume")
+ with connection.schema_editor() as editor:
+ editor.create_model(Author)
+ editor.add_field(Author, field)
+ self.assertEqual(
+ self.get_column_comment(Author._meta.db_table, "volume"),
+ comment,
+ )
+
@skipUnlessDBFeature("supports_comments")
def test_add_db_comment_and_default_charfield(self):
comment = "Custom comment with default"
}}}
It appears that the problem is due to the order the the `COMMENT` and
`GENERATED` clause in the generated SQL.
MySQL expects `COMMENT` to come after `GENERATED` while we do the opposite
{{{#!python
ALTER TABLE `schema_author` ADD COLUMN `volume` integer COMMENT 'Custom
comment' GENERATED ALWAYS AS (1) STORED
}}}
Crashes while
{{{#!python
ALTER TABLE `schema_author` ADD COLUMN `volume` integer GENERATED ALWAYS
AS (1) STORED COMMENT 'Custom comment'
}}}
passes.
--
Ticket URL: <https://code.djangoproject.com/ticket/35839#comment:1>
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