Django-rest-framework: Unhandled exception traceback hides exception original string on python 2.7

[coagulant]

After commit e3686aca93a8224280b38b7669342bcadb24176e (3.5.1 version) python 2.7 traceback for unhandled exceptions no longer contain line where exception occured, because we're reraising exception explicitly.

  File "/Users/coagulant/.envs/myproject/lib/python2.7/site-packages/rest_framework/viewsets.py", line 83, in view
    return self.dispatch(request, *args, **kwargs)
  File "/Users/coagulant/.envs/myproject/lib/python2.7/site-packages/rest_framework/views.py", line 477, in dispatch
    response = self.handle_exception(exc)
  File "/Users/coagulant/.envs/myproject/lib/python2.7/site-packages/rest_framework/views.py", line 437, in handle_exception
    self.raise_uncaught_exception(exc)
  File "/Users/coagulant/.envs/myproject/lib/python2.7/site-packages/rest_framework/views.py", line 448, in raise_uncaught_exception
    raise exc
KeyError: 'request'

Full tracebacks:

Traceback on DRF 3.5.0 (good behavior)

Traceback (most recent call last):
  File "/Users/coagulant/projects/myproject/project/tests/api/account_tests.py", line 346, in test_put_account_detail_restricted_fields_200
    {'email': u'[email protected]'})
  File "/Users/coagulant/.envs/myproject/lib/python2.7/site-packages/rest_framework/test.py", line 307, in put
    path, data=data, format=format, content_type=content_type, **extra)
  File "/Users/coagulant/.envs/myproject/lib/python2.7/site-packages/rest_framework/test.py", line 225, in put
    return self.generic('PUT', path, data, content_type, **extra)
  File "/Users/coagulant/.envs/myproject/lib/python2.7/site-packages/django/test/client.py", line 380, in generic
    return self.request(**r)
  File "/Users/coagulant/projects/myproject/project/tests/fixtures/clients.py", line 27, in request
    return super(DRFAPIClient, self).request(**kwargs)
  File "/Users/coagulant/projects/myproject/project/tests/fixtures/clients.py", line 17, in request
    return super(AutoPrependBasePathMixin, self).request(**kwargs)
  File "/Users/coagulant/.envs/myproject/lib/python2.7/site-packages/rest_framework/test.py", line 288, in request
    return super(APIClient, self).request(**kwargs)
  File "/Users/coagulant/.envs/myproject/lib/python2.7/site-packages/rest_framework/test.py", line 240, in request
    request = super(APIRequestFactory, self).request(**kwargs)
  File "/Users/coagulant/.envs/myproject/lib/python2.7/site-packages/django/test/client.py", line 449, in request
    response = self.handler(environ)
  File "/Users/coagulant/.envs/myproject/lib/python2.7/site-packages/django/test/client.py", line 123, in __call__
    response = self.get_response(request)
  File "/Users/coagulant/.envs/myproject/lib/python2.7/site-packages/rest_framework/test.py", line 260, in get_response
    return super(ForceAuthClientHandler, self).get_response(request)
  File "/Users/coagulant/.envs/myproject/lib/python2.7/site-packages/django/core/handlers/base.py", line 230, in get_response
    response = self.handle_uncaught_exception(request, resolver, sys.exc_info())
  File "/Users/coagulant/.envs/myproject/lib/python2.7/site-packages/django/core/handlers/base.py", line 149, in get_response
    response = self.process_exception_by_middleware(e, request)
  File "/Users/coagulant/.envs/myproject/lib/python2.7/site-packages/django/core/handlers/base.py", line 147, in get_response
    response = wrapped_callback(request, *callback_args, **callback_kwargs)
  File "/Users/coagulant/.envs/myproject/lib/python2.7/site-packages/django/views/decorators/csrf.py", line 58, in wrapped_view
    return view_func(*args, **kwargs)
  File "/Users/coagulant/.envs/myproject/lib/python2.7/site-packages/rest_framework/viewsets.py", line 83, in view
    return self.dispatch(request, *args, **kwargs)
  File "/Users/coagulant/.envs/myproject/lib/python2.7/site-packages/rest_framework/views.py", line 477, in dispatch
    response = self.handle_exception(exc)
  File "/Users/coagulant/.envs/myproject/lib/python2.7/site-packages/rest_framework/views.py", line 437, in handle_exception
    self.raise_uncaught_exception(exc)
  File "/Users/coagulant/.envs/myproject/lib/python2.7/site-packages/rest_framework/views.py", line 474, in dispatch
    response = handler(request, *args, **kwargs)
  File "/Users/coagulant/.envs/myproject/lib/python2.7/site-packages/rest_framework/mixins.py", line 78, in update
    return Response(serializer.data)
  File "/Users/coagulant/.envs/myproject/lib/python2.7/site-packages/rest_framework/serializers.py", line 504, in data
    ret = super(Serializer, self).data
  File "/Users/coagulant/.envs/myproject/lib/python2.7/site-packages/rest_framework/serializers.py", line 239, in data
    self._data = self.to_representation(self.instance)
  File "/Users/coagulant/.envs/myproject/lib/python2.7/site-packages/rest_framework/serializers.py", line 473, in to_representation
    ret[field.field_name] = field.to_representation(attribute)
  File "/Users/coagulant/.envs/myproject/lib/python2.7/site-packages/rest_framework/relations.py", line 371, in to_representation
    url = self.get_url(value, self.view_name, request, format)
  File "/Users/coagulant/projects/myproject/project/api/serializers.py", line 19, in get_url
    version = kwargs['request'].version
KeyError: 'request'

Traceback on DRF 3.5.1 (unexpected behavior)

Traceback (most recent call last):
  File "/Users/coagulant/projects/myproject/project/tests/api/account_tests.py", line 346, in test_put_account_detail_restricted_fields_200
    {'email': u'[email protected]'})
  File "/Users/coagulant/.envs/myproject/lib/python2.7/site-packages/rest_framework/test.py", line 307, in put
    path, data=data, format=format, content_type=content_type, **extra)
  File "/Users/coagulant/.envs/myproject/lib/python2.7/site-packages/rest_framework/test.py", line 225, in put
    return self.generic('PUT', path, data, content_type, **extra)
  File "/Users/coagulant/.envs/myproject/lib/python2.7/site-packages/django/test/client.py", line 380, in generic
    return self.request(**r)
  File "/Users/coagulant/projects/myproject/project/tests/fixtures/clients.py", line 27, in request
    return super(DRFAPIClient, self).request(**kwargs)
  File "/Users/coagulant/projects/myproject/project/tests/fixtures/clients.py", line 17, in request
    return super(AutoPrependBasePathMixin, self).request(**kwargs)
  File "/Users/coagulant/.envs/myproject/lib/python2.7/site-packages/rest_framework/test.py", line 288, in request
    return super(APIClient, self).request(**kwargs)
  File "/Users/coagulant/.envs/myproject/lib/python2.7/site-packages/rest_framework/test.py", line 240, in request
    request = super(APIRequestFactory, self).request(**kwargs)
  File "/Users/coagulant/.envs/myproject/lib/python2.7/site-packages/django/test/client.py", line 449, in request
    response = self.handler(environ)
  File "/Users/coagulant/.envs/myproject/lib/python2.7/site-packages/django/test/client.py", line 123, in __call__
    response = self.get_response(request)
  File "/Users/coagulant/.envs/myproject/lib/python2.7/site-packages/rest_framework/test.py", line 260, in get_response
    return super(ForceAuthClientHandler, self).get_response(request)
  File "/Users/coagulant/.envs/myproject/lib/python2.7/site-packages/django/core/handlers/base.py", line 230, in get_response
    response = self.handle_uncaught_exception(request, resolver, sys.exc_info())
  File "/Users/coagulant/.envs/myproject/lib/python2.7/site-packages/django/core/handlers/base.py", line 149, in get_response
    response = self.process_exception_by_middleware(e, request)
  File "/Users/coagulant/.envs/myproject/lib/python2.7/site-packages/django/core/handlers/base.py", line 147, in get_response
    response = wrapped_callback(request, *callback_args, **callback_kwargs)
  File "/Users/coagulant/.envs/myproject/lib/python2.7/site-packages/django/views/decorators/csrf.py", line 58, in wrapped_view
    return view_func(*args, **kwargs)
  File "/Users/coagulant/.envs/myproject/lib/python2.7/site-packages/rest_framework/viewsets.py", line 83, in view
    return self.dispatch(request, *args, **kwargs)
  File "/Users/coagulant/.envs/myproject/lib/python2.7/site-packages/rest_framework/views.py", line 477, in dispatch
    response = self.handle_exception(exc)
  File "/Users/coagulant/.envs/myproject/lib/python2.7/site-packages/rest_framework/views.py", line 437, in handle_exception
    self.raise_uncaught_exception(exc)
  File "/Users/coagulant/.envs/myproject/lib/python2.7/site-packages/rest_framework/views.py", line 448, in raise_uncaught_exception
    raise exc
KeyError: 'request'

[xordoquy]

Missed that line and agreed, raising should preserve the stack so it's either a raw raise or drf will have to backfeed the traceback

[tomchristie]

Most of all what I've learned from this...

Is how to use <details><summary> in GitHub issues. 👍

[tomchristie]

Okay, so the change there was in response to https://github.com/tomchristie/django-rest-framework/pull/4600 "raise with no arguments can only be used in an except clause as of Python 3.5."

Any suggestions for how to proceed?

[coagulant]

Okay, so the change there was in response to #4600 "raise with no arguments can only be used in an except clause as of Python 3.5."
Any suggestions for how to proceed?

I suppose handle_exception is called inside an except clause, and there was no problem in the first place?

[tomchristie]

Yup, given that we already test against 3.5, it's not clear what the perceived issue is.