Fix dropped message when cancelling subscription messages iterator#804
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p7g wants to merge 4 commits intonats-io:mainfrom
Open
Fix dropped message when cancelling subscription messages iterator#804p7g wants to merge 4 commits intonats-io:mainfrom
p7g wants to merge 4 commits intonats-io:mainfrom
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caspervonb
approved these changes
Feb 10, 2026
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If you have an asyncio task that iterates over messages from a subscription and you cancel it while it's waiting for the next message, there are a couple of outcomes:
get_taskgets GCed before it consumes a message, which results in a warning from the event loop's exception handler likeTask was destroyed but it is still pending!I added a regression test and made sure it was failing, then fixed the bug by cancelling
get_taskif the current task is cancelled while waiting, then made sure that the new test was passing. An existing test was publishing an extra message to work around this issue; I had to remove the workaround to make it pass.