#32595: mysql DatabaseSchemaEditor can't `quote_value` on byte strings
-------------------------------------+-------------------------------------
Reporter: Ryan | Owner: nobody
Siemens |
Type: Bug | Status: new
Component: Database | Version: 3.1
layer (models, ORM) |
Severity: Normal | Keywords:
Triage Stage: | Has patch: 0
Unreviewed |
Needs documentation: 0 | Needs tests: 0
Patch needs improvement: 0 | Easy pickings: 0
UI/UX: 0 |
-------------------------------------+-------------------------------------
Using the the `django.db.backends.mysql` backend with `mysqlclient` fails
to render the schema migration with `sqlmigrate` when using a
`BinaryField` with a binary string default value.
You can recreate this with a simple app using the following model or see
the attached sample project (MD5 = 2be52a23a4001e90728d3b0f5276e087):
{{{
class TestModel(models.Model):
ok = models.BinaryField(default=b'some-blob')
# add this after the initial migration
# not_ok = models.BinaryField(default=b'some-other-blob')
}}}
Then perform the following steps:
1. run initial `manage.py makemigrations`
2. uncomment the `not_ok = models.BinaryField(default=b'some-other-blob')`
3. run `manage.py makemigrations` again to generate the alter table
migration
4. run `manage.py sqlmigrate <app> 0002`
5. assert the following `TypeError` is raised
{{{
Traceback (most recent call last):
File "manage.py", line 22, in <module>
main()
File "manage.py", line 18, in main
execute_from_command_line(sys.argv)
File "/Users/rsiemens/sandbox/quote_value_bug/.venv/lib/python3.8/site-
packages/django/core/management/__init__.py", line 401, in
execute_from_command_line
utility.execute()
File "/Users/rsiemens/sandbox/quote_value_bug/.venv/lib/python3.8/site-
packages/django/core/management/__init__.py", line 395, in execute
self.fetch_command(subcommand).run_from_argv(self.argv)
File "/Users/rsiemens/sandbox/quote_value_bug/.venv/lib/python3.8/site-
packages/django/core/management/base.py", line 330, in run_from_argv
self.execute(*args, **cmd_options)
File "/Users/rsiemens/sandbox/quote_value_bug/.venv/lib/python3.8/site-
packages/django/core/management/commands/sqlmigrate.py", line 29, in
execute
return super().execute(*args, **options)
File "/Users/rsiemens/sandbox/quote_value_bug/.venv/lib/python3.8/site-
packages/django/core/management/base.py", line 371, in execute
output = self.handle(*args, **options)
File "/Users/rsiemens/sandbox/quote_value_bug/.venv/lib/python3.8/site-
packages/django/core/management/commands/sqlmigrate.py", line 65, in
handle
sql_statements = loader.collect_sql(plan)
File "/Users/rsiemens/sandbox/quote_value_bug/.venv/lib/python3.8/site-
packages/django/db/migrations/loader.py", line 345, in collect_sql
state = migration.apply(state, schema_editor, collect_sql=True)
File "/Users/rsiemens/sandbox/quote_value_bug/.venv/lib/python3.8/site-
packages/django/db/migrations/migration.py", line 124, in apply
operation.database_forwards(self.app_label, schema_editor, old_state,
project_state)
File "/Users/rsiemens/sandbox/quote_value_bug/.venv/lib/python3.8/site-
packages/django/db/migrations/operations/fields.py", line 104, in
database_forwards
schema_editor.add_field(
File "/Users/rsiemens/sandbox/quote_value_bug/.venv/lib/python3.8/site-
packages/django/db/backends/mysql/schema.py", line 89, in add_field
super().add_field(model, field)
File "/Users/rsiemens/sandbox/quote_value_bug/.venv/lib/python3.8/site-
packages/django/db/backends/base/schema.py", line 487, in add_field
self.execute(sql, params)
File "/Users/rsiemens/sandbox/quote_value_bug/.venv/lib/python3.8/site-
packages/django/db/backends/base/schema.py", line 137, in execute
self.collected_sql.append((sql % tuple(map(self.quote_value, params)))
+ ending)
File "/Users/rsiemens/sandbox/quote_value_bug/.venv/lib/python3.8/site-
packages/django/db/backends/mysql/schema.py", line 55, in quote_value
quoted = self.connection.connection.escape(value,
self.connection.connection.encoders)
TypeError: bytes() argument 2 must be str, not dict
}}}
The error seems to be raised from the mysqlclient `connection.escape`, but
interestingly this works if you alter the
`self.connection.connection.encoders` right before escaping
(https://github.com/django/django/blob/main/django/db/backends/mysql/schema.py#L57)
by doing `self.connection.connection.encoders.pop(bytes)`. Looking at the
default converters mysqlclient sets up
(https://github.com/PyMySQL/mysqlclient/blob/v2.0.1/MySQLdb/converters.py#L106-L139)
I don't see a `bytes` one being added, so I'm guessing django adds it
somewhere along the way.
Using:
Python 3.8.5
MySQL 8.0.23
Django==3.1.7
mysqlclient==2.0.3
--
Ticket URL: <https://code.djangoproject.com/ticket/32595>
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