Opbeat causes 500 with invalid UUID object (AttributeError: 'UUID' object has no attribute 'int')

[blueyed]

Opbeat fails to capture an error, if there is an exception during build_msg_for_logging:

2017-02-07 15:08:47,159:ERROR:i-XXX:opbeat.errors.client:[a159f1e4e73b4e599146c88346216d04]: Unable to process log entry: 'UUID' object has no attribute 'int'
Traceback (most recent call last):
  File "…/src/django/django/core/handlers/exception.py", line 39, in inner
    response = get_response(request)
  File "…/src/django/django/core/handlers/base.py", line 187, in _get_response
    response = self.process_exception_by_middleware(e, request)
  File "…/src/django/django/core/handlers/base.py", line 185, in _get_response
    response = wrapped_callback(request, *callback_args, **callback_kwargs)
  …
  File "…/src/django/django/db/models/lookups.py", line 180, in <listcomp>
    [get_db_prep_value(v, connection, prepared=True) for v in value]
  File "…/src/django/django/db/models/fields/__init__.py", line 2371, in get_db_prep_value
    value = uuid.UUID(value)
  File "/usr/lib/python3.5/uuid.py", line 140, in __init__
    raise ValueError('badly formed hexadecimal UUID string')
ValueError: badly formed hexadecimal UUID string

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/srv/project/venv/lib/python3.5/site-packages/opbeat/contrib/django/models.py", line 188, in actually_do_stuff
    request=request)
  File "./project/settings.py", line 488, in capture
    return super().capture(event_type, request, **kwargs)
  File "/srv/project/venv/lib/python3.5/site-packages/opbeat/contrib/django/client.py", line 180, in capture
    result = super(DjangoClient, self).capture(event_type, **kwargs)
  File "/srv/project/venv/lib/python3.5/site-packages/opbeat/base.py", line 388, in capture
    extra, stack, **kwargs)
  File "/srv/project/venv/lib/python3.5/site-packages/opbeat/base.py", line 265, in build_msg_for_logging
    result = handler.capture(**kwargs)
  File "/srv/project/venv/lib/python3.5/site-packages/opbeat/events.py", line 76, in capture
    get_stack_info((iter_traceback_frames(exc_traceback)))
  File "/srv/project/venv/lib/python3.5/site-packages/opbeat/utils/stacks.py", line 243, in get_stack_info
    result = get_frame_info(frame, lineno, extended)
  File "/srv/project/venv/lib/python3.5/site-packages/opbeat/utils/stacks.py", line 227, in get_frame_info
    'vars': transform(f_locals),
  File "/srv/project/venv/lib/python3.5/site-packages/opbeat/utils/encoding.py", line 109, in transform
    ret = dict((to_unicode(k), transform_rec(v)) for k, v in six.iteritems(value))
  File "/srv/project/venv/lib/python3.5/site-packages/opbeat/utils/encoding.py", line 109, in <genexpr>
    ret = dict((to_unicode(k), transform_rec(v)) for k, v in six.iteritems(value))
  File "/srv/project/venv/lib/python3.5/site-packages/opbeat/utils/encoding.py", line 94, in <lambda>
    transform_rec = lambda o: transform(o, stack + [value], context)
  File "/srv/project/venv/lib/python3.5/site-packages/opbeat/utils/encoding.py", line 107, in transform
    ret = repr(value)
  File "/usr/lib/python3.5/uuid.py", line 221, in __repr__
    return '%s(%r)' % (self.__class__.__name__, str(self))
  File "/usr/lib/python3.5/uuid.py", line 227, in __str__
    hex = '%032x' % self.int
AttributeError: 'UUID' object has no attribute 'int'

The actual error ValueError: badly formed hexadecimal UUID string (with should result in HTTP status 400) causes an AttributeError (HTTP status 500).

I think transform/get_frame_info should be wrapped in an exception handler, to handle this in general.