Stuck on an issue?

Lightrun Answers was designed to reduce the constant googling that comes with debugging 3rd party libraries. It collects links to all the places you might be looking at while hunting down a tough bug.

And, if you’re still stuck at the end, we’re happy to hop on a call to see how we can help out.

AssertionError: invalid argspec BoundMethodArgSpecWrapper

See original GitHub issue

Traceback (most recent call last):
  File "/v/site-packages/pyanalyze/name_check_visitor.py", line 705, in visit
    ret = method(node)
  File "/v/site-packages/pyanalyze/name_check_visitor.py", line 2843, in visit_Subscript
    return_value, _ = self._get_argspec_and_check_call(
  File "/v/site-packages/pyanalyze/name_check_visitor.py", line 3372, in _get_argspec_and_check_call
    extended_argspec = self._get_argspec_from_value(callee_wrapped, node)
  File "/v/site-packages/pyanalyze/name_check_visitor.py", line 3465, in _get_argspec_from_value
    return self._get_argspec(callee_wrapped.val, node, name=name)
  File "/v/site-packages/pyanalyze/name_check_visitor.py", line 3495, in _get_argspec
    return self.arg_spec_cache.get_argspec(obj, name=name, logger=self.log)
  File "/v/site-packages/pyanalyze/arg_spec.py", line 1124, in get_argspec
    argspec = self._cached_get_argspec(obj, kwargs)
  File "/v/site-packages/pyanalyze/arg_spec.py", line 1136, in _cached_get_argspec
    extended = self._uncached_get_argspec(obj, kwargs)
  File "v/site-packages/pyanalyze/arg_spec.py", line 1161, in _uncached_get_argspec
    return BoundMethodArgSpecWrapper(argspec, KnownValue(obj.__self__))
  File "/v/site-packages/pyanalyze/arg_spec.py", line 142, in __init__
    assert isinstance(argspec, ExtendedArgSpec), "invalid argspec %r" % (argspec,)
AssertionError: invalid argspec BoundMethodArgSpecWrapper(
  argspec=ExtendedArgSpec(
    _has_return_value=False,
    arguments=[Parameter(default_value=<object object at 0x7fa6a833f990>, name='self', typ=None)],
    implementation=None,
    kwargs='kwargs',
    kwonly_args=None,
    name='GenericAlias',
    params_of_names={
      'self': Parameter(default_value=<object object at 0x7fa6a833f990>, name='self', typ=None),
      'args': Parameter(default_value=<object object at 0x7fa6a833f990>, name='args', typ=TypedValue(typ=<class 'tuple'>)),
      'kwargs': Parameter(default_value=<object object at 0x7fa6a833f990>, name='kwargs', typ=TypedValue(typ=<class 'dict'>))},
    return_value=UnresolvedValue(), starargs='args'),
    self_value=TypedValue(typ=<class 'types.GenericAlias'>))

Internal error: AssertionError(-"-) (code: internal_error)

I’m sorry the code is closed-source, I could try to track it down somehow… I get this error using Python 3.9.0b1 but not 3.8