asyncio.Condition.wait() sometimes propagates incorrect asyncio.CancelledError

[kristjanvalur]

Bug report

Bug description:

asyncio.Condition.wait() contains an edge case where a CancelledError on lock re-aquire is overwritten with a fresh CancelledError instance.

CPython versions tested on:

CPython main branch

Operating systems tested on:

Windows

Linked PRs

• GH-111693: Propagate correct asyncio.CancelledError instance out of asyncio.Condition.wait() #111694

[gvanrossum]

Hm, this issue description is rather lacking in detail, and doesn't seem to match the intricate fix in gh-111694. Could you update the initial comment?

[kristjanvalur]

Well, that was the original issue, the other changes were sort of piggybacked. Looking at the issue now after your review, I'm only really

• adding a test for Future.done() for completeness. It is redundant in the current code
• Fixing the FIFO wakeup semantics of semaphore
• Propagating the last CancelledError out of Condition.wait()
• Removing dead code
• Cleaning and improving comments.
  I'll be happy to change this once we have settled on what is going to be in the PR, if anything :)