The metrics registration must happen before the pool creation to avoid accessing a metrics of a pool before the metrics is fully created.

Author: Zhen

driver/src/main/java/org/neo4j/driver/internal/async/pool/ConnectionPoolImpl.java

@@ -179,23 +179,23 @@ public boolean isOpen()
     private ChannelPool getOrCreatePool( BoltServerAddress address )
     {
         ChannelPool pool = pools.get( address );
-        if ( pool == null )
+        if ( pool != null )
         {
-            pool = newPool( address );
+            return pool;
+        }
 
-            if ( pools.putIfAbsent( address, pool ) != null )
-            {
-                // We lost a race to create the pool, dispose of the one we created, and recurse
-                pool.close();
-                return getOrCreatePool( address );
-            }
-            else
+        synchronized ( this )
+        {
+            pool = pools.get( address );
+            if ( pool != null )
             {
-                // We added a new pool as a result we add a new metrics for the pool too
-                driverMetricsListener.addMetrics( address, this );
+                return pool;
             }
-        }
 
+            driverMetricsListener.addMetrics( address, this );
+            pool = newPool( address );
+            pools.put( address, pool );
+        }
         return pool;
     }
 

driver/src/main/java/org/neo4j/driver/internal/metrics/InternalConnectionMetrics.java

@@ -19,6 +19,7 @@
 package org.neo4j.driver.internal.metrics;
 
 import java.time.Duration;
+import java.util.Objects;
 
 import org.neo4j.driver.internal.BoltServerAddress;
 import org.neo4j.driver.internal.metrics.spi.ConnectionMetrics;
@@ -33,6 +34,7 @@ public class InternalConnectionMetrics implements ConnectionMetrics, ConnectionM
 
     public InternalConnectionMetrics( BoltServerAddress serverAddress, int connectionTimeoutMillis )
     {
+        Objects.requireNonNull( serverAddress );
         this.serverAddress = serverAddress;
         connHistogram = new InternalHistogram( Duration.ofMillis( connectionTimeoutMillis ).toNanos() );
         inUseHistogram = new InternalHistogram();

driver/src/main/java/org/neo4j/driver/internal/metrics/InternalConnectionPoolMetrics.java

@@ -20,6 +20,7 @@
 package org.neo4j.driver.internal.metrics;
 
 import java.time.Duration;
+import java.util.Objects;
 import java.util.concurrent.atomic.AtomicInteger;
 import java.util.concurrent.atomic.AtomicLong;
 
@@ -45,6 +46,9 @@ public class InternalConnectionPoolMetrics implements ConnectionPoolMetrics, Con
 
     public InternalConnectionPoolMetrics( BoltServerAddress address, ConnectionPool pool, long connAcquisitionTimeoutMs )
     {
+        Objects.requireNonNull( address );
+        Objects.requireNonNull( pool );
+
         this.address = address;
         this.pool = pool;
         this.acquisitionTimeHistogram = new InternalHistogram( Duration.ofMillis( connAcquisitionTimeoutMs ).toNanos() );

driver/src/main/java/org/neo4j/driver/internal/metrics/InternalDriverMetrics.java

@@ -19,6 +19,7 @@
 package org.neo4j.driver.internal.metrics;
 
 import java.util.Map;
+import java.util.Objects;
 import java.util.concurrent.ConcurrentHashMap;
 
 import org.neo4j.driver.internal.BoltServerAddress;
@@ -41,6 +42,7 @@ public class InternalDriverMetrics extends InternalAbstractDriverMetrics
 
     public InternalDriverMetrics( Config config )
     {
+        Objects.requireNonNull( config );
         this.config = config;
         this.connectionPoolMetrics = new ConcurrentHashMap<>();
         this.connectionMetrics = new ConcurrentHashMap<>();