Handle TypeError by reqparse with bundle errors enabled.

[grucin]

There is an unexpected behavior when type of argument in request doesn't fit with that declared in add_argument method, e.g. you have argument:

parser.add_argument('foo', type=list, location='json')

and request json is something like:

{"foo": 1}

In that case Argument.convert raise TypeError, which will not be catched because RequestParser.parse_args handle only error of ValueError instance. The TypeError message will be added as a value to argument namespace.

[intentionally-left-nil]

From my understanding of the codebase, the convert() function is supposed to (re)raise exceptions during conversion. This is handled in Argument.parse() which throws the 400 response to the user:

                        value = self.convert(value, operator)
                    except Exception as error:
                        if self.ignore:
                            continue
                        self.handle_validation_error(error)

[grucin]

I forgot to add that this is happening when bundle_errors=True. In that case method Argument.handle_validation_error will not call abort, but will return error and msg

    if current_app.config.get("BUNDLE_ERRORS", False) or bundle_errors:
        msg = {self.name: "%s" % (error_msg)}
        return error, msg
    msg = {self.name: "%s" % (error_msg)}
    flask_restful.abort(400, message=msg)

And this piece of code forwards the TypeError to args namespace:

    for arg in self.args:
        value, found = arg.parse(req, self.bundle_errors)
        if isinstance(value, ValueError):
            errors.update(found)
            found = None
        if found or arg.store_missing:
            namespace[arg.dest or arg.name] = value

[minhoryang]

+1 happened with app.config['PROPAGATE_EXCEPTIONS'] = True

Traceback (most recent call last):
  File "/usr/local/var/lib/pyenv/versions/3.4.2-server/lib/python3.4/site-packages/flask/app.py", line 1836, in __call__
    return self.wsgi_app(environ, start_response)
  File "/usr/local/var/lib/pyenv/versions/3.4.2-server/lib/python3.4/site-packages/flask/app.py", line 1820, in wsgi_app
    response = self.make_response(self.handle_exception(e))
  File "/usr/local/var/lib/pyenv/versions/3.4.2-server/lib/python3.4/site-packages/flask_restful/__init__.py", line 270, in error_router
    return original_handler(e)
  File "/usr/local/var/lib/pyenv/versions/3.4.2-server/lib/python3.4/site-packages/flask/app.py", line 1403, in handle_exception
    reraise(exc_type, exc_value, tb)
  File "/usr/local/var/lib/pyenv/versions/3.4.2-server/lib/python3.4/site-packages/flask/_compat.py", line 32, in reraise
    raise value.with_traceback(tb)
  File "/usr/local/var/lib/pyenv/versions/3.4.2-server/lib/python3.4/site-packages/flask/app.py", line 1817, in wsgi_app
    response = self.full_dispatch_request()
  File "/usr/local/var/lib/pyenv/versions/3.4.2-server/lib/python3.4/site-packages/flask/app.py", line 1477, in full_dispatch_request
    rv = self.handle_user_exception(e)
  File "/usr/local/var/lib/pyenv/versions/3.4.2-server/lib/python3.4/site-packages/flask_restful/__init__.py", line 270, in error_router
    return original_handler(e)
  File "/usr/local/var/lib/pyenv/versions/3.4.2-server/lib/python3.4/site-packages/flask/app.py", line 1381, in handle_user_exception
    reraise(exc_type, exc_value, tb)
  File "/usr/local/var/lib/pyenv/versions/3.4.2-server/lib/python3.4/site-packages/flask/_compat.py", line 32, in reraise
    raise value.with_traceback(tb)
  File "/usr/local/var/lib/pyenv/versions/3.4.2-server/lib/python3.4/site-packages/flask/app.py", line 1475, in full_dispatch_request
    rv = self.dispatch_request()
  File "/usr/local/var/lib/pyenv/versions/3.4.2-server/lib/python3.4/site-packages/flask/app.py", line 1461, in dispatch_request
    return self.view_functions[rule.endpoint](**req.view_args)
  File "/usr/local/var/lib/pyenv/versions/3.4.2-server/lib/python3.4/site-packages/flask_restful/__init__.py", line 462, in wrapper
    resp = resource(*args, **kwargs)
  File "/usr/local/var/lib/pyenv/versions/3.4.2-server/lib/python3.4/site-packages/flask/views.py", line 84, in view
    return self.dispatch_request(*args, **kwargs)
  File "/usr/local/var/lib/pyenv/versions/3.4.2-server/lib/python3.4/site-packages/flask_restful/__init__.py", line 572, in dispatch_request
    resp = meth(*args, **kwargs)
  File "/Volumes/Unsigned/server/application/models/user.py", line 55, in post
    args = self.wanted.parse_args()
  File "/usr/local/var/lib/pyenv/versions/3.4.2-server/lib/python3.4/site-packages/flask_restful/reqparse.py", line 295, in parse_args
    value, found = arg.parse(req, self.bundle_errors)
  File "/usr/local/var/lib/pyenv/versions/3.4.2-server/lib/python3.4/site-packages/flask_restful/reqparse.py", line 165, in parse
    if name in source:
TypeError: argument of type 'int' is not iterable