feat(sns): add validation of displayName for topic

packages/aws-cdk-lib/aws-sns/lib/topic.ts

@@ -296,6 +296,10 @@ export class Topic extends TopicBase {
       throw new Error(`signatureVersion must be "1" or "2", received: "${props.signatureVersion}"`);
     }
 
+    if (props.displayName && !Token.isUnresolved(props.displayName) && props.displayName.length > 100) {
+      throw new Error(`displayName must be less than or equal to 100 characters, got ${props.displayName.length}`);
+    }
+
     const resource = new CfnTopic(this, 'Resource', {
       archivePolicy: props.messageRetentionPeriodInDays ? {
         MessageRetentionPeriod: props.messageRetentionPeriodInDays,

packages/aws-cdk-lib/aws-sns/test/sns.test.ts

@@ -176,6 +176,16 @@ describe('Topic', () => {
         signatureVersion: '3',
       })).toThrow(/signatureVersion must be "1" or "2", received: "3"/);
     });
+
+    test('throw error when displayName is too long', () => {
+      const stack = new cdk.Stack();
+
+      expect(() => {
+        new sns.Topic(stack, 'MyTopic', {
+          displayName: 'a'.repeat(101),
+        });
+      }).toThrow('displayName must be less than or equal to 100 characters, got 101');
+    });
   });
 
   test('can add a policy to the topic', () => {