#22999: Impossible to generate migration for model with dynamic upload_to field
--------------------------------------------+----------------------
Reporter: Kevin Van Wilder <kevin@…> | Owner: nobody
Type: Bug | Status: new
Component: Migrations | Version: 1.7-rc-1
Severity: Normal | Keywords:
Triage Stage: Unreviewed | Has patch: 0
Easy pickings: 0 | UI/UX: 0
--------------------------------------------+----------------------
In my application I have a model which uploads forms to a specific user
directory for better file system organization:
media_root/<username>/reports/file
To accomplish this, I use the following model:
{{{
upload_dir = upload_to_student_dir('committee/reports/')
class CommitteeReport(TimeStampedModel):
user = models.ForeignKey(User)
document = models.FileField(upload_to=upload_dir)
}}}
The function defines and returns an inner function which will provide the
complete path based on the instance's user:
{{{
def upload_to_student_dir(sub_path=''):
def callable(instance, filename):
"""Dynamically returns the user directory to which this file
should be uploaded.
"""
path = "students/{0}/{1}{2}".format(instance.user.username,
sub_path, filename)
return path
return callable
}}}
Creating a migration via South seemed to have caused no problems, yet the
analysis being employed by django.db.migrations differs and generates the
following error:
{{{
Migrations for 'committee':
0001_initial.py:
- Create model CommitteeReport
Traceback (most recent call last):
File "manage.py", line 11, in <module>
execute_from_command_line(sys.argv)
File "/home/kevin/.virtualenvs/stageportfolio/local/lib/python2.7/site-
packages/django/core/management/__init__.py", line 385, in
execute_from_command_line
utility.execute()
File "/home/kevin/.virtualenvs/stageportfolio/local/lib/python2.7/site-
packages/django/core/management/__init__.py", line 377, in execute
self.fetch_command(subcommand).run_from_argv(self.argv)
File "/home/kevin/.virtualenvs/stageportfolio/local/lib/python2.7/site-
packages/django/core/management/base.py", line 288, in run_from_argv
self.execute(*args, **options.__dict__)
File "/home/kevin/.virtualenvs/stageportfolio/local/lib/python2.7/site-
packages/django/core/management/base.py", line 337, in execute
output = self.handle(*args, **options)
File "/home/kevin/.virtualenvs/stageportfolio/local/lib/python2.7/site-
packages/django/core/management/commands/makemigrations.py", line 115, in
handle
self.write_migration_files(changes)
File "/home/kevin/.virtualenvs/stageportfolio/local/lib/python2.7/site-
packages/django/core/management/commands/makemigrations.py", line 143, in
write_migration_files
migration_string = writer.as_string()
File "/home/kevin/.virtualenvs/stageportfolio/local/lib/python2.7/site-
packages/django/db/migrations/writer.py", line 124, in as_string
operation_string, operation_imports =
OperationWriter(operation).serialize()
File "/home/kevin/.virtualenvs/stageportfolio/local/lib/python2.7/site-
packages/django/db/migrations/writer.py", line 76, in serialize
arg_string, arg_imports = MigrationWriter.serialize(item)
File "/home/kevin/.virtualenvs/stageportfolio/local/lib/python2.7/site-
packages/django/db/migrations/writer.py", line 229, in serialize
item_string, item_imports = cls.serialize(item)
File "/home/kevin/.virtualenvs/stageportfolio/local/lib/python2.7/site-
packages/django/db/migrations/writer.py", line 290, in serialize
return cls.serialize_deconstructed(path, args, kwargs)
File "/home/kevin/.virtualenvs/stageportfolio/local/lib/python2.7/site-
packages/django/db/migrations/writer.py", line 205, in
serialize_deconstructed
arg_string, arg_imports = cls.serialize(arg)
File "/home/kevin/.virtualenvs/stageportfolio/local/lib/python2.7/site-
packages/django/db/migrations/writer.py", line 316, in serialize
"Could not find function %s in %s.\nPlease note that "
ValueError: Could not find function %s in %s.
Please note that due to Python 2 limitations, you cannot serialize unbound
method functions (e.g. a method declared
and used in the same class body). Please move the function into the main
module body to use migrations.
For more information, see
https://docs.djangoproject.com/en/1.7/topics/migrations/#serializing-
values
}}}
As you can see I have already moved the function into the main module, yet
the error persists.
--
Ticket URL: <https://code.djangoproject.com/ticket/22999>
Django <https://code.djangoproject.com/>
The Web framework for perfectionists with deadlines.
--
You received this message because you are subscribed to the Google Groups
"Django updates" group.
To unsubscribe from this group and stop receiving emails from it, send an email
to [email protected].
To post to this group, send email to [email protected].
To view this discussion on the web visit
https://groups.google.com/d/msgid/django-updates/081.26380277b413e20d9dc1f706d29af190%40djangoproject.com.
For more options, visit https://groups.google.com/d/optout.
