#24182: Bug with functional default and migrations
----------------------------+--------------------
Reporter: arveitch | Owner: nobody
Type: Bug | Status: new
Component: Migrations | Version: 1.7
Severity: Normal | Keywords:
Triage Stage: Unreviewed | Has patch: 0
Easy pickings: 0 | UI/UX: 0
----------------------------+--------------------
I've found a bug on all of 1.7; I've tested up to 1.7.3. The code works
fine on 1.6. I think this is a reasonably common design pattern.
Here's the models.py:
{{{
import random
from django.db import models
def generateCode(prefix=''):
while True:
code = ''.join(
# Omit I, O, 1 and 0 as they can cause confusion
random.choice('ABCDEFGHJKLMNPQRSTUVWXYZ23456789')
for i in range(7)
)
code = prefix + code
if not PromotionalCode.objects.filter(code=code).exists():
break
return code
class PromotionalCode(models.Model):
code = models.CharField(
default=generateCode, db_index=True, max_length=12, unique=True
)
value_amount = models.DecimalField(
default=0, max_digits=7, decimal_places=2
)
}}}
./manage.py migrate gives this traceback:
{{{
Applying example.0001_initial...Traceback (most recent call last):
File "./manage.py", line 10, in <module>
execute_from_command_line(sys.argv)
File
"/opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7
/site-packages/django/core/management/__init__.py", line 385, in
execute_from_command_line
utility.execute()
File
"/opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7
/site-packages/django/core/management/__init__.py", line 377, in execute
self.fetch_command(subcommand).run_from_argv(self.argv)
File
"/opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7
/site-packages/django/core/management/base.py", line 288, in run_from_argv
self.execute(*args, **options.__dict__)
File
"/opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7
/site-packages/django/core/management/base.py", line 338, in execute
output = self.handle(*args, **options)
File
"/opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7
/site-packages/django/core/management/commands/migrate.py", line 161, in
handle
executor.migrate(targets, plan, fake=options.get("fake", False))
File
"/opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7
/site-packages/django/db/migrations/executor.py", line 68, in migrate
self.apply_migration(migration, fake=fake)
File
"/opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7
/site-packages/django/db/migrations/executor.py", line 102, in
apply_migration
migration.apply(project_state, schema_editor)
File
"/opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7
/site-packages/django/db/migrations/migration.py", line 108, in apply
operation.database_forwards(self.app_label, schema_editor,
project_state, new_state)
File
"/opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7
/site-packages/django/db/migrations/operations/models.py", line 36, in
database_forwards
schema_editor.create_model(model)
File
"/opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7
/site-packages/django/db/backends/schema.py", line 213, in create_model
definition, extra_params = self.column_sql(model, field)
File
"/opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7
/site-packages/django/db/backends/schema.py", line 125, in column_sql
default_value = self.effective_default(field)
File
"/opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7
/site-packages/django/db/backends/schema.py", line 175, in
effective_default
default = field.get_default()
File
"/opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7
/site-packages/django/db/models/fields/__init__.py", line 719, in
get_default
return self.default()
File "/Users/andrew/Sites/testing/example/models.py", line 12, in
generateCode
if not PromotionalCode.objects.filter(code=code).exists():
File
"/opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7
/site-packages/django/db/models/query.py", line 606, in exists
return self.query.has_results(using=self.db)
File
"/opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7
/site-packages/django/db/models/sql/query.py", line 457, in has_results
return compiler.has_results()
File
"/opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7
/site-packages/django/db/models/sql/compiler.py", line 757, in has_results
return bool(self.execute_sql(SINGLE))
File
"/opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7
/site-packages/django/db/models/sql/compiler.py", line 786, in execute_sql
cursor.execute(sql, params)
File
"/opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7
/site-packages/django/db/backends/utils.py", line 81, in execute
return super(CursorDebugWrapper, self).execute(sql, params)
File
"/opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7
/site-packages/django/db/backends/utils.py", line 65, in execute
return self.cursor.execute(sql, params)
File
"/opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7
/site-packages/django/db/utils.py", line 94, in __exit__
six.reraise(dj_exc_type, dj_exc_value, traceback)
File
"/opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7
/site-packages/django/db/backends/utils.py", line 65, in execute
return self.cursor.execute(sql, params)
File
"/opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7
/site-packages/django/db/backends/sqlite3/base.py", line 485, in execute
return Database.Cursor.execute(self, query, params)
django.db.utils.OperationalError: no such table: example_promotionalcode
}}}
--
Ticket URL: <https://code.djangoproject.com/ticket/24182>
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