#35336: Adding GeneratedField fails with ProgrammingError when using When on
CharField
-------------------------------------+-------------------------------------
Reporter: Adrian | Owner: nobody
Garcia |
Type: Bug | Status: new
Component: | Version: 5.0
Migrations | Keywords: postgres,
Severity: Normal | generatedfield, _split_query
Triage Stage: | Has patch: 0
Unreviewed |
Needs documentation: 0 | Needs tests: 0
Patch needs improvement: 0 | Easy pickings: 0
UI/UX: 0 |
-------------------------------------+-------------------------------------
Forgive me if I am doing something incorrectly, but I cannot for the life
of me add a GeneratedField to one of my models. To replicate this error, I
created this test model:
{{{
from django.db import models
class TestModel(models.Model):
description = models.TextField()
}}}
Running makemigrations/migrate, then modifying the model to add this
`contains_heck` field:
{{{
from django.db import models
class TestModel(models.Model):
description = models.TextField()
contains_heck = models.GeneratedField(
expression=models.Case(
models.When(description__icontains="HECK",
then=models.Value(True)),
default=models.Value(False),
output_field=models.BooleanField(),
),
output_field=models.BooleanField(),
db_persist=True,
)
}}}
Which generates this migration:
{{{
# Generated by Django 5.0.3 on 2024-03-27 20:34
from django.db import migrations, models
class Migration(migrations.Migration):
dependencies = [
("core", "00001_initial"),
]
operations = [
migrations.AddField(
model_name="testmodel",
name="contains_heck",
field=models.GeneratedField(
db_persist=True,
expression=models.Case(
models.When(description__icontains="HECK",
then=models.Value(True)), default=models.Value(False),
output_field=models.BooleanField()
),
output_field=models.BooleanField(),
),
),
]
}}}
And after running `python manage.py migrate` I get the following error:
{{{
Operations to perform:
Apply all migrations: admin, auth, consumer, contenttypes, core, db,
sessions
Running migrations:
Applying core.0002_testmodel_contains_heck...Traceback (most recent call
last):
File "/opt/project/app/manage.py", line 24, in <module>
main()
File "/opt/project/app/manage.py", line 20, in main
execute_from_command_line(sys.argv)
File "/usr/local/lib/python3.11/site-
packages/django/core/management/__init__.py", line 442, in
execute_from_command_line
utility.execute()
File "/usr/local/lib/python3.11/site-
packages/django/core/management/__init__.py", line 436, in execute
self.fetch_command(subcommand).run_from_argv(self.argv)
File "/usr/local/lib/python3.11/site-
packages/django/core/management/base.py", line 413, in run_from_argv
self.execute(*args, **cmd_options)
File "/usr/local/lib/python3.11/site-
packages/django/core/management/base.py", line 459, in execute
output = self.handle(*args, **options)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/usr/local/lib/python3.11/site-
packages/django/core/management/base.py", line 107, in wrapper
res = handle_func(*args, **kwargs)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/usr/local/lib/python3.11/site-
packages/django/core/management/commands/migrate.py", line 356, in handle
post_migrate_state = executor.migrate(
^^^^^^^^^^^^^^^^^
File "/usr/local/lib/python3.11/site-
packages/django/db/migrations/executor.py", line 135, in migrate
state = self._migrate_all_forwards(
^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/usr/local/lib/python3.11/site-
packages/django/db/migrations/executor.py", line 167, in
_migrate_all_forwards
state = self.apply_migration(
^^^^^^^^^^^^^^^^^^^^^
File "/usr/local/lib/python3.11/site-
packages/django/db/migrations/executor.py", line 252, in apply_migration
state = migration.apply(state, schema_editor)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/usr/local/lib/python3.11/site-
packages/django/db/migrations/migration.py", line 132, in apply
operation.database_forwards(
File "/usr/local/lib/python3.11/site-
packages/django/db/migrations/operations/fields.py", line 108, in
database_forwards
schema_editor.add_field(
File "/usr/local/lib/python3.11/site-
packages/django/db/backends/base/schema.py", line 750, in add_field
self.execute(sql, params)
File "/usr/local/lib/python3.11/site-
packages/django/db/backends/postgresql/schema.py", line 46, in execute
sql = self.connection.ops.compose_sql(str(sql), params)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/usr/local/lib/python3.11/site-
packages/django/db/backends/postgresql/operations.py", line 195, in
compose_sql
return mogrify(sql, params, self.connection)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/usr/local/lib/python3.11/site-
packages/django/db/backends/postgresql/psycopg_any.py", line 22, in
mogrify
return ClientCursor(cursor.connection).mogrify(sql, params)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/usr/local/lib/python3.11/site-packages/psycopg/client_cursor.py",
line 40, in mogrify
pgq = self._convert_query(query, params)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/usr/local/lib/python3.11/site-packages/psycopg/client_cursor.py",
line 79, in _convert_query
pgq.convert(query, params)
File "/usr/local/lib/python3.11/site-packages/psycopg/_queries.py", line
208, in convert
(self.template, self._order, self._parts) = f(bquery, self._encoding)
^^^^^^^^^^^^^^^^^^^^^^^^^
File "/usr/local/lib/python3.11/site-packages/psycopg/_queries.py", line
242, in _query2pg_client_nocache
parts = _split_query(query, encoding, collapse_double_percent=False)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/usr/local/lib/python3.11/site-packages/psycopg/_queries.py", line
388, in _split_query
raise e.ProgrammingError(
psycopg.ProgrammingError: only '%s', '%b', '%t' are allowed as
placeholders, got '%H'
}}}
I took a look with the debugger and I think either Django is incorrectly
passing the values to psycopg, or psycopg isn't splitting this SQL
statement correctly. I say this because when `_split_query` tries to split
the query, it ends up matching and consuming the first character of each
Value:
{{{
[
('ALTER TABLE "core_testmodel" ADD COLUMN "contains_heck" boolean
GENERATED ALWAYS AS (CASE WHEN UPPER("description"::text) LIKE UPPER(\'',
"<re.Match object; span=(140, 142), match=b'%H'>"),
("ECK", '<re.Match object; span=(145, 147), match=b"%\'">'),
(") THEN true ELSE false END) STORED", "None"),
]
}}}
Switching to `models.When(description__icontains=models.Value("HECK"),
...) yields a similar error except it's complaining about `%'` instead of
`%H`.
If the `contains_heck` field is created at the same time as the rest of
the model, everything works in either the `description__icontains="HECK"`
or `description__icontains=models.Value("HECK")` configuration.
**Versions:**
* Postgres 14.9
* Python 3.11.2
* Django 5.0.3
* psycopg[binary] 3.1.18
--
Ticket URL: <https://code.djangoproject.com/ticket/35336>
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