def _get_coroutine_or_flag_problem(async_fn: Callable[..., Awaitable[Any]],
*args: Any,
**kwargs: Any) -> Awaitable[Any]:
"""Call async_fn(*args) to produce and return a coroutine. If that
doesn't work or doesn't produce a coroutine, try to get help
from trio in describing what went wrong.
"""
try:
# can we call it?
coro = async_fn(*args, **kwargs)
except TypeError:
probe_fn = async_fn
else:
# did we get a coroutine object back?
if isinstance(coro, collections.abc.Coroutine):
return coro
probe_fn = partial(async_fn, **kwargs)
# TODO: upstream a change that lets us access just the nice
# error detection logic without running the risk of starting a task
# If we're not happy with this async_fn, trio won't be either,
# and will tell us why in much greater detail.
try:
trio.hazmat.spawn_system_task(probe_fn, *args)
except TypeError as ex:
problem_with_async_fn = ex
else:
# we started the task successfully, wtf?
raise trio.TrioInternalError(
"tried to spawn a dummy task to figure out what was wrong with "
"{async_fn!r} as an async function, but it seems to have started "
"successfully -- all bets are off at this point")
raise problem_with_async_fn
def fget(self):
if self.crashed and not self._error_list:
self._error_list.append(trio.TrioInternalError("See pytest-trio issue #75"))
return self._error_list
