xds: Implement equals in WRRLBConfig

Just an is a8de9f0, lack of equals causes cluster_resolver to consider every update a different configuration and restart itself.

Handling NaN should really be prevented with validation, but it looks like that
would lead to yak shaving at the moment.

b/435208946

Author: ejona86

xds/src/main/java/io/grpc/xds/WeightedRoundRobinLoadBalancer.java

@@ -48,6 +48,7 @@
 import java.util.Collection;
 import java.util.HashSet;
 import java.util.List;
+import java.util.Objects;
 import java.util.Random;
 import java.util.Set;
 import java.util.concurrent.ScheduledExecutorService;
@@ -738,6 +739,32 @@ private WeightedRoundRobinLoadBalancerConfig(long blackoutPeriodNanos,
       this.errorUtilizationPenalty = errorUtilizationPenalty;
     }
 
+    @Override
+    public boolean equals(Object o) {
+      if (!(o instanceof WeightedRoundRobinLoadBalancerConfig)) {
+        return false;
+      }
+      WeightedRoundRobinLoadBalancerConfig that = (WeightedRoundRobinLoadBalancerConfig) o;
+      return this.blackoutPeriodNanos == that.blackoutPeriodNanos
+          && this.weightExpirationPeriodNanos == that.weightExpirationPeriodNanos
+          && this.enableOobLoadReport == that.enableOobLoadReport
+          && this.oobReportingPeriodNanos == that.oobReportingPeriodNanos
+          && this.weightUpdatePeriodNanos == that.weightUpdatePeriodNanos
+          // Float.compare considers NaNs equal
+          && Float.compare(this.errorUtilizationPenalty, that.errorUtilizationPenalty) == 0;
+    }
+
+    @Override
+    public int hashCode() {
+      return Objects.hash(
+          blackoutPeriodNanos,
+          weightExpirationPeriodNanos,
+          enableOobLoadReport,
+          oobReportingPeriodNanos,
+          weightUpdatePeriodNanos,
+          errorUtilizationPenalty);
+    }
+
     static final class Builder {
       long blackoutPeriodNanos = 10_000_000_000L; // 10s
       long weightExpirationPeriodNanos = 180_000_000_000L; //3min

xds/src/test/java/io/grpc/xds/WeightedRoundRobinLoadBalancerTest.java

@@ -35,6 +35,7 @@
 import com.google.common.collect.ImmutableMap;
 import com.google.common.collect.Lists;
 import com.google.common.collect.Maps;
+import com.google.common.testing.EqualsTester;
 import com.google.protobuf.Duration;
 import io.grpc.Attributes;
 import io.grpc.CallOptions;
@@ -215,6 +216,40 @@ public void pickChildLbTF() throws Exception {
     weightedPicker.pickSubchannel(mockArgs);
   }
 
+  @Test
+  public void config_equalsTester() {
+    WeightedRoundRobinLoadBalancerConfig defaults =
+        WeightedRoundRobinLoadBalancerConfig.newBuilder().build();
+    new EqualsTester()
+        .addEqualityGroup(
+            WeightedRoundRobinLoadBalancerConfig.newBuilder().build(),
+            WeightedRoundRobinLoadBalancerConfig.newBuilder().build(),
+            WeightedRoundRobinLoadBalancerConfig.newBuilder()
+              .setBlackoutPeriodNanos(defaults.blackoutPeriodNanos).build())
+        .addEqualityGroup(
+            WeightedRoundRobinLoadBalancerConfig.newBuilder()
+              .setBlackoutPeriodNanos(5).build())
+        .addEqualityGroup(
+            WeightedRoundRobinLoadBalancerConfig.newBuilder()
+              .setWeightExpirationPeriodNanos(5).build())
+        .addEqualityGroup(
+            WeightedRoundRobinLoadBalancerConfig.newBuilder()
+              .setEnableOobLoadReport(true).build())
+        .addEqualityGroup(
+            WeightedRoundRobinLoadBalancerConfig.newBuilder()
+              .setOobReportingPeriodNanos(5).build())
+        .addEqualityGroup(
+            WeightedRoundRobinLoadBalancerConfig.newBuilder()
+              .setWeightUpdatePeriodNanos(5).build())
+        .addEqualityGroup(
+            WeightedRoundRobinLoadBalancerConfig.newBuilder()
+              .setErrorUtilizationPenalty(0.5F).build())
+        .addEqualityGroup(
+            WeightedRoundRobinLoadBalancerConfig.newBuilder()
+              .setErrorUtilizationPenalty(Float.NaN).build())
+        .testEquals();
+  }
+
   @Test
   public void wrrLifeCycle() {
     syncContext.execute(() -> wrr.acceptResolvedAddresses(ResolvedAddresses.newBuilder()