xds: fix clusterImplLoadBalancer NPE when lrs is null (#8713)

YifeiZhuang · web-flow · commit 8382bd8e0434 · 2021-11-18T14:30:35.000-08:00
diff --git a/xds/src/main/java/io/grpc/xds/ClusterImplLoadBalancer.java b/xds/src/main/java/io/grpc/xds/ClusterImplLoadBalancer.java
@@ -319,9 +319,11 @@ public PickResult pickSubchannel(PickSubchannelArgs args) {
           }
           final ClusterLocalityStats stats =
               result.getSubchannel().getAttributes().get(ATTR_CLUSTER_LOCALITY_STATS);
-          ClientStreamTracer.Factory tracerFactory = new CountingStreamTracerFactory(
-              stats, inFlights, result.getStreamTracerFactory());
-          return PickResult.withSubchannel(result.getSubchannel(), tracerFactory);
+          if (stats != null) {
+            ClientStreamTracer.Factory tracerFactory = new CountingStreamTracerFactory(
+                stats, inFlights, result.getStreamTracerFactory());
+            return PickResult.withSubchannel(result.getSubchannel(), tracerFactory);
+          }
         }
         return result;
       }

Original file line number	Diff line number	Diff line change
`@@ -319,9 +319,11 @@ public PickResult pickSubchannel(PickSubchannelArgs args) {`
`319`	`319`	`}`
`320`	`320`	`final ClusterLocalityStats stats =`
`321`	`321`	`result.getSubchannel().getAttributes().get(ATTR_CLUSTER_LOCALITY_STATS);`
`322`		`- ClientStreamTracer.Factory tracerFactory = new CountingStreamTracerFactory(`
`323`		`- stats, inFlights, result.getStreamTracerFactory());`
`324`		`- return PickResult.withSubchannel(result.getSubchannel(), tracerFactory);`
	`322`	`+ if (stats != null) {`
	`323`	`+ ClientStreamTracer.Factory tracerFactory = new CountingStreamTracerFactory(`
	`324`	`+ stats, inFlights, result.getStreamTracerFactory());`
	`325`	`+ return PickResult.withSubchannel(result.getSubchannel(), tracerFactory);`
	`326`	`+ }`
`325`	`327`	`}`
`326`	`328`	`return result;`
`327`	`329`	`}`