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Channel context manager eats exceptions when cancelled #746
Description
I ran into this today:
import trio
async def produce(send_channel):
async with send_channel:
print("in async with send_channel")
raise RuntimeError("kaboom")
async def test():
send_channel, receive_channel = trio.open_memory_channel(0)
with trio.open_cancel_scope() as scope:
scope.cancel()
await produce(send_channel)
trio.run(test)
print("where's the kaboom?")
Prints:
in async with send_channel
where's the kaboom?
I'm guessing this is because channel.aclose() is a checkpoint? Seems like this exception-eating might be the same or an overlapping issue as #455, but it was especially surprising to me, and I think might create user confusion as people start using async with foo_channel: in more and more places.
Activity
m-u-xyz commentedon Oct 23, 2018
It is. There's not much that Trio can do internally to fix that IMHO, but what about a
context manager that packages the exception(s) raised by
foo, and the traceback if one exists, into aMultiError(or whatever Python's stdlib ends up naming the thing)? At least then we'd have a standard idiom that we can use, and the one additional line of boilerplate won't hurt (too much) (and can be checked for by a linter).njsmith commentedon Oct 23, 2018
Yeah, this is exactly the same as #455, so I'll close it to consolidate the discussion.