Ensure user-allocated cancel scope just works!
Turns out the nursery doesn't have to care about allocating a per task
`CancelScope` since the user can just do that in the
`@task_scope_manager` if desired B) So just mask all the nursery cs
allocating with the intention of removal.
Also add a test for per-task-cancellation by starting the crash task as
a `trio.sleep_forever()` but then cancel it via the user allocated cs
and ensure the crash propagates as expected 💥
Tyler Goodlet
parent
49c35f06ae
commit
311a1e6d55
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@ -126,18 +126,23 @@ class ScopePerTaskNursery(Struct):
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# task = new_tasks.pop()
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n: Nursery = self._n
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cs = CancelScope()
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sm = self.scope_manager
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# we do default behavior of a scope-per-nursery
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# if the user did not provide a task manager.
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if sm is None:
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return n.start_soon(async_fn, *args, name=None)
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# per_task_cs = CancelScope()
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new_task: Task | None = None
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to_return: tuple[Any] | None = None
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sm = self.scope_manager
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if sm is None:
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mngr = nullcontext([cs])
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else:
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# NOTE: what do we enforce as a signature for the
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# `@task_scope_manager` here?
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mngr = sm(nursery=n)
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mngr = sm(
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nursery=n,
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# scope=per_task_cs,
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)
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async def _start_wrapped_in_scope(
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task_status: TaskStatus[
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tuple[CancelScope, Task]
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@ -148,10 +153,12 @@ class ScopePerTaskNursery(Struct):
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# TODO: this was working before?!
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# nonlocal to_return
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with cs:
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task = trio.lowlevel.current_task()
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self._scopes[cs] = task
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# self._scopes[per_task_cs] = task
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# NOTE: we actually don't need this since the user can
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# just to it themselves inside mngr!
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# with per_task_cs:
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# execute up to the first yield
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try:
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@ -178,8 +185,7 @@ class ScopePerTaskNursery(Struct):
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try:
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mngr.send(outcome)
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# NOTE: this will instead send the underlying
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# `.value`? Not sure if that's better or not?
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# I would presume it's better to have a handle to
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# the `Outcome` entirely? This method sends *into*
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# the mngr this `Outcome.value`; seems like kinda
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@ -200,7 +206,6 @@ class ScopePerTaskNursery(Struct):
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return to_return
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# TODO: you could wrap your output task handle in this?
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# class TaskHandle(Struct):
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# task: Task
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@ -214,6 +219,11 @@ class ScopePerTaskNursery(Struct):
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def add_task_handle_and_crash_handling(
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nursery: Nursery,
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# TODO: is this the only way we can have a per-task scope
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# allocated or can we allow the user to somehow do it if
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# they want below?
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# scope: CancelScope,
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) -> Generator[None, list[Any]]:
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task_outcome = TaskOutcome()
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@ -222,8 +232,12 @@ def add_task_handle_and_crash_handling(
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task: Task = trio.lowlevel.current_task()
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print(f'Spawning task: {task.name}')
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# yields back when task is terminated, cancelled, returns.
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try:
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# yields back when task is terminated, cancelled, returns?
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# XXX: wait, this isn't doing anything right since we'd have to
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# manually activate this scope using something like:
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# `task._activate_cancel_status(cs._cancel_status)` ??
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# oh wait, but `.__enter__()` does all that already?
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with CancelScope() as cs:
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# the yielded value(s) here are what are returned to the
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@ -260,6 +274,19 @@ async def sleep_then_return_val(val: str):
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return val
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async def ensure_cancelled():
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try:
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await trio.sleep_forever()
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except trio.Cancelled:
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task = trio.lowlevel.current_task()
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print(f'heyyo ONLY {task.name} was cancelled as expected B)')
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assert 0
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except BaseException:
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raise RuntimeError("woa woa woa this ain't right!")
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if __name__ == '__main__':
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async def main():
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@ -267,17 +294,22 @@ if __name__ == '__main__':
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scope_manager=add_task_handle_and_crash_handling,
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) as sn:
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for _ in range(3):
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outcome, cs = await sn.start_soon(trio.sleep_forever)
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outcome, _ = await sn.start_soon(trio.sleep_forever)
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# extra task we want to engage in debugger post mortem.
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err_outcome, *_ = await sn.start_soon(sleep_then_err)
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err_outcome, cs = await sn.start_soon(ensure_cancelled)
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val: str = 'yoyoyo'
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val_outcome, cs = await sn.start_soon(sleep_then_return_val, val)
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val_outcome, _ = await sn.start_soon(
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sleep_then_return_val,
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val,
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)
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res = await val_outcome.wait_for_result()
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assert res == val
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print(f'GOT EXPECTED TASK VALUE: {res}')
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print(f'{res} -> GOT EXPECTED TASK VALUE')
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print('WAITING FOR CRASH..')
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await trio.sleep(0.6)
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print('Cancelling and waiting for CRASH..')
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cs.cancel()
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trio.run(main)
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Reference in New Issue