Unable to sqaush migrations that use RunSQL operations with state_operations

[Simon Kelly]

As a workaround to this bug: https://code.djangoproject.com/ticket/25817 I have the following custom migration:

operations = [
        migrations.RunSQL(
            'ALTER TABLE form_processor_bar RENAME COLUMN bar_id TO external_id',
            'ALTER TABLE form_processor_bar RENAME COLUMN external_id TO bar_id',
            state_operations=[
                migrations.RenameField(
                    model_name='bar',
                    old_name='bar_id',
                    new_name='external_id',
                ),
                migrations.AlterField(
                    model_name='bazz',
                    name='bar',
                    field=models.ForeignKey(to='form_processor.Bar', to_field=b'external_id'),
                    preserve_default=True,
                ),
            ]
        )
    ]

When I try and squash this migration I get the following error:

$ ./manage.py squashmigrations form_processor 0002
Will squash the following migrations:
 - 0001_initial
 - 0002_rename_bar_id_to_external_id
Do you wish to proceed? [yN] y
Optimizing...
Traceback (most recent call last):
  File "./manage.py", line 73, in <module>
    execute_from_command_line(sys.argv)
  File "/home/skelly/.virtualenvs/hq/local/lib/python2.7/site-packages/django/core/management/__init__.py", line 385, in execute_from_command_line
    utility.execute()
  File "/home/skelly/.virtualenvs/hq/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/skelly/.virtualenvs/hq/local/lib/python2.7/site-packages/django/core/management/base.py", line 288, in run_from_argv
    self.execute(*args, **options.__dict__)
  File "/home/skelly/.virtualenvs/hq/local/lib/python2.7/site-packages/django/core/management/base.py", line 338, in execute
    output = self.handle(*args, **options)
  File "/home/skelly/.virtualenvs/hq/local/lib/python2.7/site-packages/django/core/management/commands/squashmigrations.py", line 130, in handle
    fh.write(writer.as_string())
  File "/home/skelly/.virtualenvs/hq/local/lib/python2.7/site-packages/django/db/migrations/writer.py", line 131, in as_string
    operation_string, operation_imports = OperationWriter(operation).serialize()
  File "/home/skelly/.virtualenvs/hq/local/lib/python2.7/site-packages/django/db/migrations/writer.py", line 88, in serialize
    arg_string, arg_imports = MigrationWriter.serialize(arg_value)
  File "/home/skelly/.virtualenvs/hq/local/lib/python2.7/site-packages/django/db/migrations/writer.py", line 263, in serialize
    item_string, item_imports = cls.serialize(item)
  File "/home/skelly/.virtualenvs/hq/local/lib/python2.7/site-packages/django/db/migrations/writer.py", line 350, in serialize
    return cls.serialize_deconstructed(*value.deconstruct())
  File "/home/skelly/.virtualenvs/hq/local/lib/python2.7/site-packages/django/db/migrations/writer.py", line 226, in serialize_deconstructed
    module, name = path.rsplit(".", 1)
ValueError: need more than 1 value to unpack

On further examination it seems that the 'path' to the operation is being passed in without the module reference i.e. 'RenameField' instead of 'migrations.RenameField'. It's also possible that something else is going wrong since all the other paths being passed to 'serialize_deconstructed' are for actual field classes e.g. 'django.db.models.CharField'.