When running some test cases via py.test and using a coroutine created inside of cythonized code, I get the following:

   def _format_coroutine(coro):
        assert iscoroutine(coro)
        coro_name = getattr(coro, '__qualname__', coro.__name__)
    
        filename = coro.gi_code.co_filename
        if (isinstance(coro, CoroWrapper)
        and not inspect.isgeneratorfunction(coro.func)):
>           filename, lineno = events._get_function_source(coro.func)
E           TypeError: 'NoneType' object is not iterable


This appears to be because this line:

https://github.com/python/asyncio/blob/2a19f9329f4ee710fef7728b316aa4fe1d07dbef/asyncio/coroutines.py#L289

Is expecting to get back two values, but because of:

https://github.com/python/asyncio/blob/master/asyncio/events.py#L35

This it only gets back None.


> /usr/local/lib/python3.4/asyncio/events.py(25)_get_function_source()
-> if _PY34:
(Pdb) func
<cyfunction ProgressTracker._do_report at 0x7fdd2fc46498>

Thanks! I've fixed this in the git repo now (https://github.com/python/asyncio/commit/0c3e6ec0340f45d5f6989391358d44b8e974858e). It will be merged into the CPython repo at the next opportunity (before 3.5.2).

Merged in f4fe55dd5659.