Random exception: cannot set the body to a unicode value

[dread]

Occasionally see this problem when producing an error page. Here's an example

WebApp Error: <type 'exceptions.TypeError'>: You cannot set the body to a unicode value without a charset
URL: http://at.ckan.net/authorizationgroup/new
Module weberror.errormiddleware:162 in __call__
<<              __traceback_supplement__ = Supplement, self, environ
                   sr_checker = ResponseStartChecker(start_response)
                   app_iter = self.application(environ, sr_checker)
                   return self.make_catching_iter(app_iter, environ, sr_checker)
               except:
>>  app_iter = self.application(environ, sr_checker)
Module beaker.middleware:73 in __call__
<<                                                     self.cache_manager)
               environ[self.environ_key] = self.cache_manager
               return self.app(environ, start_response)
>>  return self.app(environ, start_response)
Module beaker.middleware:152 in __call__
<<                          headers.append(('Set-cookie', cookie))
                   return start_response(status, headers, exc_info)
               return self.wrap_app(environ, session_start_response)
           
           def _get_session(self):
>>  return self.wrap_app(environ, session_start_response)
Module routes.middleware:130 in __call__
<<                  environ['SCRIPT_NAME'] = environ['SCRIPT_NAME'][:-1]
               
               response = self.app(environ, start_response)
               
               # Wrapped in try as in rare cases the attribute will be gone already
>>  response = self.app(environ, start_response)
Module pylons.wsgiapp:125 in __call__
<<          
               controller = self.resolve(environ, start_response)
               response = self.dispatch(controller, environ, start_response)
               
               if 'paste.testing_variables' in environ and hasattr(response,
>>  response = self.dispatch(controller, environ, start_response)
Module pylons.wsgiapp:324 in dispatch
<<          if log_debug:
                   log.debug("Calling controller class with WSGI interface")
               return controller(environ, start_response)
           
           def load_test_env(self, environ):
>>  return controller(environ, start_response)
Module ckan.lib.base:117 in __call__
<<          # available in environ['pylons.routes_dict']    
               try:
                   return WSGIController.__call__(self, environ, start_response)
               finally:
                   model.Session.remove()
>>  return WSGIController.__call__(self, environ, start_response)
Module pylons.controllers.core:284 in __call__
<<              if log_debug:
                       log.debug("Calling Response object to return WSGI data")
                   return response(environ, self.start_response)
               
               if log_debug:
>>  return response(environ, self.start_response)
Module webob.exc:248 in __call__
<<              return []
               if not self.body and not self.empty_body:
                   return self.generate_response(environ, start_response)
               return Response.__call__(self, environ, start_response)
>>  return self.generate_response(environ, start_response)
Module webob.exc:239 in generate_response
<<              status=self.status,
                   headerlist=headerlist,
                   content_type=content_type
               )
               return resp(environ, start_response)
>>  content_type=content_type
Module webob.response:94 in __init__
<<                  if charset is None:
                           raise TypeError(
                               "You cannot set the body to a unicode value without a charset")
                       body = body.encode(charset)
                   self._body = body
>>  "You cannot set the body to a unicode value without a charset")
TypeError: You cannot set the body to a unicode value without a charset

[dread]

John thinks it is a problem with WebOb? 1.0.6

[dread]

This error has been occurring on at.ckan.net which has webob 0.9.7.1-1

[dread]

Running tests with WebOb? 0.9.7.1, we see the error! Am now trying to fix.

[dread]

Fixed in cset:db5bf5b45b4f for ckan 1.4.3.

Later versions of webob add the charset header for unicode errors (webob/exc.py:generate_response):

        extra_kw = {}
        if isinstance(body, unicode):
            extra_kw.update(charset='utf-8')
        resp = Response(body,
            status=self.status,
            headerlist=headerlist,
            content_type=content_type,
            **extra_kw
        )

This was fixed in webob cset:25fc14d49623 which went into WebOb? 1.0.

This problem affects versions from CKAN 1.4.2 back to 1.3.1. We had been avoiding this in CKAN previously by only doing abort() with a plain string.