refactor: downgrade unhandled notification logging from error to warn

tzolov · tzolov · commit 110a8d1940ca · 2025-08-06T08:34:30.000+01:00
- Change logger.error() to logger.warn() for unhandled notification methods
- Log full notification object instead of just method name for better context
- Affects McpClientSession, McpServerSession, and McpStreamableServerSession

Signed-off-by: Christian Tzolov &lt;christian.tzolov@broadcom.com&gt;
diff --git a/mcp/src/main/java/io/modelcontextprotocol/spec/McpClientSession.java b/mcp/src/main/java/io/modelcontextprotocol/spec/McpClientSession.java
@@ -221,7 +221,7 @@ private Mono<Void> handleIncomingNotification(McpSchema.JSONRPCNotification noti
 		return Mono.defer(() -> {
 			var handler = notificationHandlers.get(notification.method());
 			if (handler == null) {
-				logger.error("No handler registered for notification method: {}", notification.method());
+				logger.warn("No handler registered for notification method: {}", notification);
 				return Mono.empty();
 			}
 			return handler.handle(notification.params());
diff --git a/mcp/src/main/java/io/modelcontextprotocol/spec/McpServerSession.java b/mcp/src/main/java/io/modelcontextprotocol/spec/McpServerSession.java
@@ -294,7 +294,7 @@ private Mono<Void> handleIncomingNotification(McpSchema.JSONRPCNotification noti
 
 			var handler = notificationHandlers.get(notification.method());
 			if (handler == null) {
-				logger.error("No handler registered for notification method: {}", notification.method());
+				logger.warn("No handler registered for notification method: {}", notification);
 				return Mono.empty();
 			}
 			return this.exchangeSink.asMono().flatMap(exchange -> handler.handle(exchange, notification.params()));
diff --git a/mcp/src/main/java/io/modelcontextprotocol/spec/McpStreamableServerSession.java b/mcp/src/main/java/io/modelcontextprotocol/spec/McpStreamableServerSession.java
@@ -197,7 +197,7 @@ public Mono<Void> accept(McpSchema.JSONRPCNotification notification) {
 			McpTransportContext transportContext = ctx.getOrDefault(McpTransportContext.KEY, McpTransportContext.EMPTY);
 			McpNotificationHandler notificationHandler = this.notificationHandlers.get(notification.method());
 			if (notificationHandler == null) {
-				logger.error("No handler registered for notification method: {}", notification.method());
+				logger.warn("No handler registered for notification method: {}", notification);
 				return Mono.empty();
 			}
 			McpLoggableSession listeningStream = this.listeningStreamRef.get();

Original file line number	Diff line number	Diff line change
`@@ -221,7 +221,7 @@ private Mono<Void> handleIncomingNotification(McpSchema.JSONRPCNotification noti`
`221`	`221`	`return Mono.defer(() -> {`
`222`	`222`	`var handler = notificationHandlers.get(notification.method());`
`223`	`223`	`if (handler == null) {`
`224`		`- logger.error("No handler registered for notification method: {}", notification.method());`
	`224`	`+ logger.warn("No handler registered for notification method: {}", notification);`
`225`	`225`	`return Mono.empty();`
`226`	`226`	`}`
`227`	`227`	`return handler.handle(notification.params());`
Original file line number	Diff line number	Diff line change
`@@ -294,7 +294,7 @@ private Mono<Void> handleIncomingNotification(McpSchema.JSONRPCNotification noti`
`294`	`294`
`295`	`295`	`var handler = notificationHandlers.get(notification.method());`
`296`	`296`	`if (handler == null) {`
`297`		`- logger.error("No handler registered for notification method: {}", notification.method());`
	`297`	`+ logger.warn("No handler registered for notification method: {}", notification);`
`298`	`298`	`return Mono.empty();`
`299`	`299`	`}`
`300`	`300`	`return this.exchangeSink.asMono().flatMap(exchange -> handler.handle(exchange, notification.params()));`
Original file line number	Diff line number	Diff line change
`@@ -197,7 +197,7 @@ public Mono<Void> accept(McpSchema.JSONRPCNotification notification) {`
`197`	`197`	`McpTransportContext transportContext = ctx.getOrDefault(McpTransportContext.KEY, McpTransportContext.EMPTY);`
`198`	`198`	`McpNotificationHandler notificationHandler = this.notificationHandlers.get(notification.method());`
`199`	`199`	`if (notificationHandler == null) {`
`200`		`- logger.error("No handler registered for notification method: {}", notification.method());`
	`200`	`+ logger.warn("No handler registered for notification method: {}", notification);`
`201`	`201`	`return Mono.empty();`
`202`	`202`	`}`
`203`	`203`	`McpLoggableSession listeningStream = this.listeningStreamRef.get();`