Return a closed channel instead of nil for getChannelOrErrorParallel #64
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Thanks for the catch and the fix! |
ajnavarro
approved these changes
Dec 2, 2022
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Can we add a regression test here proving this now addresses the observed behavior? |
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@BigLep added here thanks to @guseggert #66 |
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Returning nil causes functions ranging over the channel to block indefinitely but returning a closed channel doesn't. In our specific case, go-bitswap was hanging on it and after a few canceled requests, would no longer reach out to IPFS indexers via go-delegated-routing.
Here's the line that would hang. Discovered via a pprof goroutine dump.
https://github.com/ipfs/go-bitswap/blob/13c89f1ba6c65253a3dfc3b2bafcb1730b320b66/network/ipfs_impl.go#L382
Thanks @Anshul-Birla for extensive help with debugging this.