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Eliminate NPE after recovering from a temporary name resolution failure. #11298

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merged 3 commits into from
Jun 21, 2024

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larry-safran
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Fixes #11227

@@ -180,10 +180,18 @@ public Status acceptResolvedAddresses(ResolvedAddresses resolvedAddresses) {

@Override
public void handleNameResolutionError(Status error) {
if (rawConnectivityState == SHUTDOWN) {
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Was this introduced to avoid NPE and handle the case of acceptResolvedAddresses being called when the state is SHUTDOWN ? Can we add test for this as well?

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Eric pointed out that it shouldn't be possible to get into that state, so I don't think we can add a test. I was being overly cautious in case someone messed up the logic in the future.

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FWIW, at some point we should make PF continue using the old addresses in the face of resolution errors.

@@ -196,7 +204,7 @@ void processSubchannelState(Subchannel subchannel, ConnectivityStateInfo stateIn
if (subchannelData == null || subchannelData.getSubchannel() != subchannel) {
return;
}
if (newState == SHUTDOWN) {
if (newState == SHUTDOWN || rawConnectivityState == SHUTDOWN) {
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if rawConnectivityState == SHUTDOWN then subchannelData == null. Thus is this change is guaranteed to do nothing. It seems fair to rely on subchannelData == null.

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done.

if (addressIndex != null) {
addressIndex.updateGroups(null);
}
rawConnectivityState = IDLE;
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Am I right in believing this line is the main fix?

Can things work if we use TF here instead? That might be less prone to error.

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Yes, lines 191-193 are the critical part and I think having an appropriate rawConnectivityState state may be helpful and is definitely a good idea. Changed it to be TF instead of IDLE.

@larry-safran larry-safran merged commit 9b39b3e into grpc:master Jun 21, 2024
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@larry-safran larry-safran deleted the PFLeaf_fix branch June 21, 2024 20:20
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