Fixed memory object stream sometimes dropping sent items #735
+126
−57
Conversation
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Check if the receiving task has a pending cancellation before sending an item. Fixes #728.
Zac-HD
approved these changes
May 22, 2024
Comment on lines
-66
to
+70
| :return: a list of task info objects | ||
| :return: a sequence of task info objects |
There was a problem hiding this comment.
If we want this to be a general Sequence, let's also update the type annotation above and cast below.
Comment on lines
+209
to
+210
| while self._state.waiting_receivers: | ||
| receive_event, receiver = self._state.waiting_receivers.popitem(last=False) |
There was a problem hiding this comment.
I suspect that this can deadlock if the receiving task is cancelled, then send_nowait invoked (removing it from the waiting_receivers), and then uncancelled before the event loop actually kicks the receiving task out of await receive.
Of course this is a pretty nasty use of the already brittle uncancel semantics, but we probably want a comment here to make the possibility salient to future readers? Or maybe I'm wrong about this.
Comment on lines
+346
to
+348
| cancel_scope.cancel() | ||
| send.send_nowait("item") | ||
|
|
There was a problem hiding this comment.
from comment above: uncancelling that scope is my maybe-deadlock.
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
Changes
Fixes #728.
Checklist
If this is a user-facing code change, like a bugfix or a new feature, please ensure that
you've fulfilled the following conditions (where applicable):
tests/) added which would fail without your patchdocs/, in case of behavior changes or newfeatures)
docs/versionhistory.rst).If this is a trivial change, like a typo fix or a code reformatting, then you can ignore
these instructions.
Updating the changelog
If there are no entries after the last release, use
**UNRELEASED**as the version.If, say, your patch fixes issue #123, the entry should look like this:
* Fix big bad boo-boo in task groups (#123 <https://github.com/agronholm/anyio/issues/123>_; PR by Yourname)If there's no issue linked, just link to your pull request instead by updating the
changelog after you've created the PR.
If possible, use your real name in the changelog entry. If not, use your GitHub
username.