Fix racy shutdown logic #11
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There are two issues with the shutdown logic: 1. If Close() is called before the eventLoop is scheduled, the WaitGroup counter is still 0 and Close does not wait for the eventLoop to finish. That's a race condition 2. If Close() is called more than once, it panics, as the code tries to write to a closed channel. It is generally good practice to make Close idempotent, to allow the defer x.Close(); /* … */ return x.Close() idiom, which is a convenient way to guarantee both that Close is called *and* that the error is checked. This commit fixes both and factors the shutdown logic into a new type for readability and ease of understanding.
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Hey, thank you. It is nicer that Close() is idempotent for the user. |
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There are two issues with the shutdown logic:
Close()is called before theeventLoopis scheduled, theWaitGroupcounter is still 0 andClosedoes not wait for theeventLoopto finish. That's a race conditionClose()is called more than once, it panics, as the code tries to write to a closed channel. It is generally good practice to makeCloseidempotent, to allow thedefer x.Close(); /* … */ return x.Close()idiom, which is a convenient way to guarantee both thatCloseis called and that the error is checked.This commit fixes both and factors the shutdown logic into a new type for readability and ease of understanding.