The real issue is if the root nursery gets cancelled prior to
de-registration with the arbiter. This doesn't seem easy to
reproduce by side effect of a KBI however that is how it was
discovered in practise.
There was code from the last de-registration fix PR that I had commented
(to do with shielding arbiter dereg steps in `Actor._async_main()`) because
the block didn't seem to make a difference under infinite streaming
tests. Turns out it **for sure** is needed under certain conditions (likely
if the actor's root nursery is cancelled prior to actor nursery exit).
This was an attempt to simulate the failure mode if you manually close the
stream **before** cancelling the containing **actor**.
More tests to come I guess.
This truly reproduces #141. It turns out the problem only occurs when
we're cancelled in the middle of consuming "infinite streams".
Good news is this tests a lot of edge cases :)
Tyler Goodlet
Tyler Goodlet
Christian López Barrón