les: fix retriever logic #17705
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les: fix retriever logic #17705
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nizsheanez
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in nizsheanez/go-ethereum
Sep 21, 2018
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This PR fixes stateRequesting() behavior in the retriever state machine.
It is always assumed that tryRequest is called before entering stateRequesting and an rpSent event will occur. If ev.peer != nil then we stay in requesting state and assume that either a delivery or a soft timeout event will follow. The existing implementation did not handle rpDeliveredInvalid though in which case it stayed in stateRequesting while no further event was happening in relation to that request, resulting in a deadlock. This PR handles rpDeliveredInvalid similarly to rpSoftTimeout, initiating a new request attempt and then staying in stateRequesting.
It also fixes a minor bug in stateNoMorePeers() to properly exit when there is nothing to wait for any more, similarly to stateRequesting. This missing condition did not cause a noticeable trouble because case <-time.After(retryQueue) saved the situation, going to stateRequesting and then not going back to stateNoMorePeers if not necessary but exiting properly instead.