Throw exception when notification configuration is not supported

This update introduces a new `UnsupportedFeatureException`. An instance of this exception will be emitted if a custom `NotificationConfig` is used and the driver comes across a Bolt connection that does not support the notification configuration.

Author: injectives

driver/src/main/java/org/neo4j/driver/Config.java

@@ -32,6 +32,7 @@
 import java.util.Objects;
 import java.util.concurrent.TimeUnit;
 import java.util.logging.Level;
+import org.neo4j.driver.exceptions.UnsupportedFeatureException;
 import org.neo4j.driver.internal.SecuritySettings;
 import org.neo4j.driver.internal.async.pool.PoolSettings;
 import org.neo4j.driver.internal.cluster.RoutingSettings;
@@ -775,7 +776,10 @@ public ConfigBuilder withUserAgent(String userAgent) {
         /**
          * Sets notification config.
          * <p>
-         * This configuration is supported over Bolt protocol version 5.2 and above.
+         * Any configuration other than the {@link NotificationConfig#defaultConfig()} requires a minimum Bolt protocol
+         * version 5.2. Otherwise, an {@link UnsupportedFeatureException} will be emitted when the driver comes across a
+         * Bolt connection that does not support this feature. For instance, when running a query.
+         *
          * @param notificationConfig the notification config
          * @return this builder
          * @since 5.7

driver/src/main/java/org/neo4j/driver/NotificationConfig.java

@@ -22,21 +22,31 @@
 import java.util.Set;
 import org.neo4j.driver.internal.InternalNotificationConfig;
 import org.neo4j.driver.internal.InternalNotificationSeverity;
+import org.neo4j.driver.summary.ResultSummary;
 
 /**
- * Notification configuration that defines what notifications the server should supply to the driver.
+ * A notification configuration defining what notifications should be supplied by the server.
  * <p>
- * This configuration is only supported over Bolt protocol version 5.2 and above. It is effectively ignored on the previous versions.
+ * There are currently 2 optional settings that may be activated:
+ * <ul>
+ *     <li>Minimum notification severity - sets a baseline severity for notifications, similar to the logging levels.</li>
+ *     <li>A set of disabled notification categories - explicitly disables a set of notification categories.</li>
+ * </ul>
+ * <p>
+ * By default, both options are not activated.
  *
  * @since 5.7
+ * @see ResultSummary#notifications()
+ * @see org.neo4j.driver.summary.Notification
  */
 public sealed interface NotificationConfig extends Serializable permits InternalNotificationConfig {
     /**
-     * Returns a default notification config.
+     * Returns a default notification configuration.
      * <p>
-     * It has no options activated, meaning the resulting behaviour depends on an upstream entity. For instance,
-     * when this config is set on the session level, the resulting behaviour depends on the driver's config.
-     * Likewise, when this config is set on the driver level, the resulting behaviour depends on the server.
+     * The default configuration has no settings activated, meaning the resulting behaviour depends on an upstream
+     * context. For instance, when this config is set on the session level, the resulting behaviour depends on the
+     * driver's config. Likewise, when this config is set on the driver level, the resulting behaviour depends on the
+     * server.
      *
      * @return the default config
      */
@@ -49,7 +59,7 @@ static NotificationConfig defaultConfig() {
      *
      * @return the config that disables all notifications
      */
-    static NotificationConfig disableAll() {
+    static NotificationConfig disableAllConfig() {
         return new InternalNotificationConfig(InternalNotificationSeverity.OFF, null);
     }
 

driver/src/main/java/org/neo4j/driver/SessionConfig.java

@@ -27,6 +27,7 @@
 import java.util.Objects;
 import java.util.Optional;
 import org.neo4j.driver.async.AsyncSession;
+import org.neo4j.driver.exceptions.UnsupportedFeatureException;
 import org.neo4j.driver.reactive.ReactiveSession;
 import org.neo4j.driver.reactive.RxSession;
 import org.neo4j.driver.util.Experimental;
@@ -385,7 +386,10 @@ public Builder withBookmarkManager(BookmarkManager bookmarkManager) {
         /**
          * Sets notification config.
          * <p>
-         * This configuration is supported over Bolt protocol version 5.2 and above.
+         * Any configuration other than the {@link NotificationConfig#defaultConfig()} requires a minimum Bolt protocol
+         * version 5.2. Otherwise, an {@link UnsupportedFeatureException} will be emitted when the driver comes across a
+         * Bolt connection that does not support this feature. For instance, when running a query.
+         *
          * @param notificationConfig the notification config
          * @return this builder
          * @since 5.7

driver/src/main/java/org/neo4j/driver/exceptions/UnsupportedFeatureException.java

@@ -0,0 +1,47 @@
+/*
+ * Copyright (c) "Neo4j"
+ * Neo4j Sweden AB [http://neo4j.com]
+ *
+ * This file is part of Neo4j.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.neo4j.driver.exceptions;
+
+import java.io.Serial;
+
+/**
+ * A feature is not supported in a given setup.
+ * @since 5.7
+ */
+public class UnsupportedFeatureException extends ClientException {
+    @Serial
+    private static final long serialVersionUID = 1161333003602398544L;
+
+    /**
+     * Constructs a new instance.
+     * @param message the message
+     */
+    public UnsupportedFeatureException(String message) {
+        super(message);
+    }
+
+    /**
+     * Constructs a new instance.
+     * @param message the message
+     * @param cause the cause
+     */
+    public UnsupportedFeatureException(String message, Throwable cause) {
+        super(message, cause);
+    }
+}

driver/src/main/java/org/neo4j/driver/internal/cluster/RediscoveryImpl.java

@@ -43,6 +43,7 @@
 import org.neo4j.driver.exceptions.FatalDiscoveryException;
 import org.neo4j.driver.exceptions.SecurityException;
 import org.neo4j.driver.exceptions.ServiceUnavailableException;
+import org.neo4j.driver.exceptions.UnsupportedFeatureException;
 import org.neo4j.driver.internal.BoltServerAddress;
 import org.neo4j.driver.internal.DomainNameResolver;
 import org.neo4j.driver.internal.ImpersonationUtil;
@@ -296,6 +297,8 @@ private boolean mustAbortDiscovery(Throwable throwable) {
         } else if (throwable instanceof IllegalStateException
                 && ConnectionPool.CONNECTION_POOL_CLOSED_ERROR_MESSAGE.equals(throwable.getMessage())) {
             abort = true;
+        } else if (throwable instanceof UnsupportedFeatureException) {
+            abort = true;
         } else if (throwable instanceof ClientException) {
             String code = ((ClientException) throwable).code();
             abort = switch (code) {

driver/src/main/java/org/neo4j/driver/internal/messaging/v3/BoltProtocolV3.java

@@ -37,6 +37,8 @@
 import org.neo4j.driver.NotificationConfig;
 import org.neo4j.driver.Query;
 import org.neo4j.driver.TransactionConfig;
+import org.neo4j.driver.exceptions.Neo4jException;
+import org.neo4j.driver.exceptions.UnsupportedFeatureException;
 import org.neo4j.driver.internal.DatabaseBookmark;
 import org.neo4j.driver.internal.DatabaseName;
 import org.neo4j.driver.internal.async.UnmanagedTransaction;
@@ -82,6 +84,11 @@ public void initializeChannel(
             RoutingContext routingContext,
             ChannelPromise channelInitializedPromise,
             NotificationConfig notificationConfig) {
+        var exception = verifyNotificationConfigSupported(notificationConfig);
+        if (exception != null) {
+            channelInitializedPromise.setFailure(exception);
+            return;
+        }
         Channel channel = channelInitializedPromise.channel();
         HelloMessage message;
 
@@ -91,14 +98,14 @@ public void initializeChannel(
                     ((InternalAuthToken) authToken).toMap(),
                     routingContext.toMap(),
                     includeDateTimeUtcPatchInHello(),
-                    includeNotificationSettings() ? notificationConfig : null);
+                    notificationConfig);
         } else {
             message = new HelloMessage(
                     userAgent,
                     ((InternalAuthToken) authToken).toMap(),
                     null,
                     includeDateTimeUtcPatchInHello(),
-                    includeNotificationSettings() ? notificationConfig : null);
+                    notificationConfig);
         }
 
         HelloResponseHandler handler = new HelloResponseHandler(channelInitializedPromise);
@@ -125,6 +132,10 @@ public CompletionStage<Void> beginTransaction(
             TransactionConfig config,
             String txType,
             NotificationConfig notificationConfig) {
+        var exception = verifyNotificationConfigSupported(notificationConfig);
+        if (exception != null) {
+            return CompletableFuture.failedStage(exception);
+        }
         try {
             verifyDatabaseNameBeforeTransaction(connection.databaseName());
         } catch (Exception error) {
@@ -139,7 +150,7 @@ public CompletionStage<Void> beginTransaction(
                 connection.mode(),
                 connection.impersonatedUser(),
                 txType,
-                includeNotificationSettings() ? notificationConfig : null);
+                notificationConfig);
         connection.writeAndFlush(beginMessage, new BeginTxResponseHandler(beginTxFuture));
         return beginTxFuture;
     }
@@ -167,6 +178,10 @@ public ResultCursorFactory runInAutoCommitTransaction(
             TransactionConfig config,
             long fetchSize,
             NotificationConfig notificationConfig) {
+        var exception = verifyNotificationConfigSupported(notificationConfig);
+        if (exception != null) {
+            throw exception;
+        }
         verifyDatabaseNameBeforeTransaction(connection.databaseName());
         RunWithMetadataMessage runMessage = autoCommitTxRunMessage(
                 query,
@@ -175,7 +190,7 @@ public ResultCursorFactory runInAutoCommitTransaction(
                 connection.mode(),
                 bookmarks,
                 connection.impersonatedUser(),
-                includeNotificationSettings() ? notificationConfig : null);
+                notificationConfig);
         return buildResultCursorFactory(connection, query, bookmarkConsumer, null, runMessage, fetchSize);
     }
 
@@ -214,7 +229,13 @@ protected boolean includeDateTimeUtcPatchInHello() {
         return false;
     }
 
-    protected boolean includeNotificationSettings() {
-        return false;
+    protected Neo4jException verifyNotificationConfigSupported(NotificationConfig notificationConfig) {
+        Neo4jException exception = null;
+        if (notificationConfig != null && !notificationConfig.equals(NotificationConfig.defaultConfig())) {
+            exception = new UnsupportedFeatureException(String.format(
+                    "Notification configuration is not supported on Bolt %s",
+                    version().toString()));
+        }
+        return exception;
     }
 }

driver/src/main/java/org/neo4j/driver/internal/messaging/v51/BoltProtocolV51.java

@@ -46,6 +46,11 @@ public void initializeChannel(
             RoutingContext routingContext,
             ChannelPromise channelInitializedPromise,
             NotificationConfig notificationConfig) {
+        var exception = verifyNotificationConfigSupported(notificationConfig);
+        if (exception != null) {
+            channelInitializedPromise.setFailure(exception);
+            return;
+        }
         var channel = channelInitializedPromise.channel();
         HelloMessage message;
 

driver/src/main/java/org/neo4j/driver/internal/messaging/v52/BoltProtocolV52.java

@@ -24,6 +24,7 @@
 import java.util.Collections;
 import org.neo4j.driver.AuthToken;
 import org.neo4j.driver.NotificationConfig;
+import org.neo4j.driver.exceptions.Neo4jException;
 import org.neo4j.driver.internal.cluster.RoutingContext;
 import org.neo4j.driver.internal.handlers.HelloResponseHandler;
 import org.neo4j.driver.internal.handlers.LogonResponseHandler;
@@ -62,8 +63,8 @@ public void initializeChannel(
     }
 
     @Override
-    protected boolean includeNotificationSettings() {
-        return true;
+    protected Neo4jException verifyNotificationConfigSupported(NotificationConfig notificationConfig) {
+        return null;
     }
 
     @Override