fix(core): messages are displayed multiple times per construct (#24019)

Annotations added many times clog terminal space and make debugging difficult. Deduplicate annotations based on the message.

Closes #9565.

----

*By submitting this pull request, I confirm that my contribution is made under the terms of the Apache-2.0 license*

packages/@aws-cdk/core/lib/annotations.ts

@@ -1,8 +1,6 @@
 import * as cxschema from '@aws-cdk/cloud-assembly-schema';
 import * as cxapi from '@aws-cdk/cx-api';
-import { IConstruct, Node } from 'constructs';
-
-const DEPRECATIONS_SYMBOL = Symbol.for('@aws-cdk/core.deprecations');
+import { IConstruct } from 'constructs';
 
 /**
  * Includes API for attaching annotations such as warning messages to constructs.
@@ -77,38 +75,23 @@ export class Annotations {
 
     // throw if CDK_BLOCK_DEPRECATIONS is set
     if (process.env.CDK_BLOCK_DEPRECATIONS) {
-      throw new Error(`${Node.of(this.scope).path}: ${text}`);
-    }
-
-    // de-dup based on api key
-    const set = this.deprecationsReported;
-    if (set.has(api)) {
-      return;
+      throw new Error(`${this.scope.node.path}: ${text}`);
     }
 
     this.addWarning(text);
-    set.add(api);
   }
 
   /**
    * Adds a message metadata entry to the construct node, to be displayed by the CDK CLI.
+   *
+   * Records the message once per construct.
    * @param level The message level
    * @param message The message itself
    */
   private addMessage(level: string, message: string) {
-    Node.of(this.scope).addMetadata(level, message, { stackTrace: this.stackTraces });
-  }
-
-  /**
-   * Returns the set of deprecations reported on this construct.
-   */
-  private get deprecationsReported() {
-    let set = (this.scope as any)[DEPRECATIONS_SYMBOL];
-    if (!set) {
-      set = new Set();
-      Object.defineProperty(this.scope, DEPRECATIONS_SYMBOL, { value: set });
+    const isNew = !this.scope.node.metadata.find((x) => x.data === message);
+    if (isNew) {
+      this.scope.node.addMetadata(level, message, { stackTrace: this.stackTraces });
     }
-
-    return set;
   }
 }

packages/@aws-cdk/core/test/annotations.test.ts

@@ -1,7 +1,7 @@
 import { Construct } from 'constructs';
+import { getWarnings } from './util';
 import { App, Stack } from '../lib';
 import { Annotations } from '../lib/annotations';
-import { getWarnings } from './util';
 
 const restore = process.env.CDK_BLOCK_DEPRECATIONS;
 
@@ -74,4 +74,23 @@ describe('annotations', () => {
     process.env.CDK_BLOCK_DEPRECATIONS = '1';
     expect(() => Annotations.of(c1).addDeprecation('foo', 'bar')).toThrow(/MyStack\/Hello: The API foo is deprecated: bar\. This API will be removed in the next major release/);
   });
+
+  test('addMessage deduplicates the message on the node level', () => {
+    const app = new App();
+    const stack = new Stack(app, 'S1');
+    const c1 = new Construct(stack, 'C1');
+    Annotations.of(c1).addWarning('You should know this!');
+    Annotations.of(c1).addWarning('You should know this!');
+    Annotations.of(c1).addWarning('You should know this!');
+    Annotations.of(c1).addWarning('You should know this, too!');
+    expect(getWarnings(app.synth())).toEqual([{
+      path: '/S1/C1',
+      message: 'You should know this!',
+    },
+    {
+      path: '/S1/C1',
+      message: 'You should know this, too!',
+    }],
+    );
+  });
 });