sync: fix missing notification during mpsc close #2854
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When the mpsc channel receiver closes the channel, receiving should return `None` once all in-progress sends have completed. When a sender reserves capacity, this prevents the receiver from fully shutting down. Previously, when the sender, after reserving capacity, dropped without sending a message, the receiver was not notified. This results in blocking the shutdown process until all sender handles drop. This patch adds a receiver notification when the channel is both closed and all outstanding sends have completed.
Darksonn
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Darksonn
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| self.inner.semaphore.drop_permit(&mut self.permit); | ||
| let notify = self.inner.semaphore.drop_permit(&mut self.permit); | ||
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| if notify && self.inner.semaphore.is_idle() { |
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Does is_idle mean that no permits are currently taken?
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As an additional note, I am in the process of changing most of this code for 0.3. |
Darksonn
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Sep 21, 2020
hawkw
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Sep 21, 2020
carllerche
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When the mpsc channel receiver closes the channel, receiving should return `None` once all in-progress sends have completed. When a sender reserves capacity, this prevents the receiver from fully shutting down. Previously, when the sender, after reserving capacity, dropped without sending a message, the receiver was not notified. This results in blocking the shutdown process until all sender handles drop. This patch adds a receiver notification when the channel is both closed and all outstanding sends have completed.
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When the mpsc channel receiver closes the channel, receiving should
return
Noneonce all in-progress sends have completed. When a senderreserves capacity, this prevents the receiver from fully shutting down.
Previously, when the sender, after reserving capacity, dropped without
sending a message, the receiver was not notified. This results in
blocking the shutdown process until all sender handles drop.
This patch adds a receiver notification when the channel is both closed
and all outstanding sends have completed.