[FIXED] Fix Subscription.StatusChanged channel closure on Closed Subscription#2034
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[FIXED] Fix Subscription.StatusChanged channel closure on Closed Subscription#2034nithimani38-prog wants to merge 2 commits intonats-io:mainfrom
nithimani38-prog wants to merge 2 commits intonats-io:mainfrom
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The Subscription.StatusChanged godoc mentions that the returned channel will be closed when the subscription is closed. However, this is the case only if the subscription is closed after the StatusChanged channel is created and registered to listen for changes. To prevent consumers from waiting on signals from closed subscriptions, lets close the channel if the current status of the Subscription is already SubscriptionClosed. We run this check in a defer statement to avoid races against the subscription status changing and allow backward compatibility with usages that expect to receive the current status. Signed-off-by: Nithilan Manimaran Pugazhendhi <nithilan.pugazhendhi@imc.com>
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Signed-off-by: Nithilan Manimaran Pugazhendhi <nithilan.pugazhendhi@imc.com>
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Mar 25, 2026
| ch := make(chan SubStatus, 10) | ||
| s.mu.Lock() | ||
| defer s.mu.Unlock() | ||
| defer func() { |
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With this approach, the listener is already registered (tored in a map) when you're closing the channel. Why not simply return a closed channel if a subscription is closed- not in defer, but before registering it. Since StatusChanged keeps the subscription lock, this should be safe and the subscription will never be closed concurrently.
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The Subscription.StatusChanged godoc mentions that the returned channel will be closed when the subscription is closed. However, this is the case only if the subscription is closed after the StatusChanged channel is created and registered to listen for changes.
To prevent consumers from waiting on signals from closed subscriptions, lets close the channel if the current status of the Subscription is already SubscriptionClosed. We run this check in a defer statement to avoid races against the subscription status changing and allow backward compatibility with usages that expect to receive the current status.