TypeError: Error when calling the metaclass bases

[realtkd]

Hi.

I tried to get a local version of AraPheno running but it seems there is some conflict with the autocomplete_light which causes the process to bail out with

TypeError: Error when calling the metaclass bases metaclass conflict: the metaclass of a derived class must be a (non-strict) subclass of the metaclasses of all its bases

This appears to be a problem of autocomplete_light version 2.3.3 (see their issue #914). I tried the latest version of autocomplete_light without success. Since you apparently have a version running at https://arapheno.1001genomes.org, I was wondering if you could check the requirements in this repo to see if there are any differences w.r.t. to the production system?

[dominikgrimm]

Hi,

I just cloned the repo and created a new virtual environment for testing. I do not have any problems. It works fine for me. Do you have sqlite3 installed?

Googling your error I found this on Stackoverflow:

https://stackoverflow.com/questions/11276037/python-3-typeerror-metaclass-conflict-the-metaclass-of-a-derived-class-must-b

[realtkd]

Hi,

thanks for the feedback. I did the very same thing (clone, virtual env with python version 2.7.5) and yes, sqlite3 is installed. I re-cloned the repo, just to be sure, but the error persist. The full Traceback is:

$ manage.py runserver

Unhandled exception in thread started by <function wrapper at 0x4067a28>
Traceback (most recent call last):
  File "/home/michael/projects/arapheno/venv2.7/lib/python2.7/site-packages/django/utils/autoreload.py", line 226, in wrapper
    fn(*args, **kwargs)
  File "/home/michael/projects/arapheno/venv2.7/lib/python2.7/site-packages/django/core/management/commands/runserver.py", line 109, in inner_run
    autoreload.raise_last_exception()
  File "/home/michael/projects/arapheno/venv2.7/lib/python2.7/site-packages/django/utils/autoreload.py", line 249, in raise_last_exception
    six.reraise(*_exception)
  File "/home/michael/projects/arapheno/venv2.7/lib/python2.7/site-packages/django/utils/autoreload.py", line 226, in wrapper
    fn(*args, **kwargs)
  File "/home/michael/projects/arapheno/venv2.7/lib/python2.7/site-packages/django/__init__.py", line 18, in setup
    apps.populate(settings.INSTALLED_APPS)
  File "/home/michael/projects/arapheno/venv2.7/lib/python2.7/site-packages/django/apps/registry.py", line 115, in populate 
    app_config.ready()
  File "/home/michael/projects/arapheno/venv2.7/lib/python2.7/site-packages/autocomplete_light/apps.py", line 9, in ready 
    autodiscover()
  File "/home/michael/projects/arapheno/venv2.7/lib/python2.7/site-packages/autocomplete_light/registry.py", line 327, in autodiscover
    autodiscover_modules('autocomplete_light_registry')
  File "/home/michael/projects/arapheno/venv2.7/lib/python2.7/site-packages/django/utils/module_loading.py", line 50, in autodiscover_modules
    import_module('%s.%s' % (app_config.name, module_to_search))
  File "/usr/lib64/python2.7/importlib/__init__.py", line 37, in import_module
    __import__(name)
  File "/home/michael/projects/arapheno/arapheno/home/autocomplete_light_registry.py", line 4, in <module> 
    from autocomplete_light import shortcuts as autocomplete_light
  File "/home/michael/projects/arapheno/venv2.7/lib/python2.7/site-packages/autocomplete_light/shortcuts.py", line 8, in <module> 
    from .forms import *
  File "/home/michael/projects/arapheno/venv2.7/lib/python2.7/site-packages/autocomplete_light/forms.py", line 438, in <module> 
    class ModelForm(six.with_metaclass(*bases)):
  File "/home/michael/projects/arapheno/venv2.7/lib/python2.7/site-packages/autocomplete_light/forms.py", line 283, in __new__
    attrs)
  File "/home/michael/projects/arapheno/venv2.7/lib/python2.7/site-packages/django/forms/models.py", line 208, in __new__
    new_class = super(ModelFormMetaclass, mcs).__new__(mcs, name, bases, attrs)
  File "/home/michael/projects/arapheno/venv2.7/lib/python2.7/site-packages/django/forms/forms.py", line 42, in __new__
    .__new__(mcs, name, bases, attrs))
  File "/home/michael/projects/arapheno/venv2.7/lib/python2.7/site-packages/django/forms/widgets.py", line 152, in __new__
    .__new__(mcs, name, bases, attrs))
TypeError: Error when calling the metaclass bases
    metaclass conflict: the metaclass of a derived class must be a (non-strict) subclass of the metaclasses of all its bases  

[realtkd]

I found the solution. The six package is not listed in the requirements so its latest version (1.11.0) get s pulled in as a dependency which causes the above error. When explicitly installing six version 1.9.0 (pip install six==1.9.0) everything works as expected.

[dominikgrimm]

thanks for finding the issue. I will add it to the dependency list.