fix(core): --debug doesn't record stack traces (#21931)

In v1 we used to record construct stack traces; those have disappeared
in v2 because the defaults in the underlying `constructs` library
changed.

Re-add them when `--debug` is passed.

----

*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/cfn-element.ts

@@ -1,6 +1,7 @@
 import * as cxschema from '@aws-cdk/cloud-assembly-schema';
 import * as cxapi from '@aws-cdk/cx-api';
 import { Construct, Node } from 'constructs';
+import { debugModeEnabled } from './debug';
 import { Lazy } from './lazy';
 
 const CFN_ELEMENT_SYMBOL = Symbol.for('@aws-cdk/core.CfnElement');
@@ -71,6 +72,7 @@ export abstract class CfnElement extends Construct {
 
     if (!this.node.tryGetContext(cxapi.DISABLE_LOGICAL_ID_METADATA)) {
       Node.of(this).addMetadata(cxschema.ArtifactMetadataEntryType.LOGICAL_ID, this.logicalId, {
+        stackTrace: debugModeEnabled(),
         traceFromFunction: this.constructor,
       });
     }
@@ -204,3 +206,4 @@ function notTooLong(x: string) {
 import { CfnReference } from './private/cfn-reference';
 import { Stack } from './stack';
 import { Token } from './token';
+

packages/@aws-cdk/core/test/cfn-resource.test.ts

@@ -1,3 +1,4 @@
+import * as cxschema from '@aws-cdk/cloud-assembly-schema';
 import { VALIDATE_SNAPSHOT_REMOVAL_POLICY } from '@aws-cdk/cx-api';
 import { Construct } from 'constructs';
 import * as core from '../lib';
@@ -255,4 +256,23 @@ describe('cfn resource', () => {
       });
     }).toThrow(/should be created in the scope of a Stack, but no Stack found/);
   });
+
+  test('CfnResource has logical ID metadata with stack trace attached', () => {
+    process.env.CDK_DEBUG = '1';
+    try {
+      const app = new core.App();
+      const stack = new core.Stack(app, 'Stack');
+      const res = new core.CfnResource(stack, 'SomeCfnResource', {
+        type: 'Some::Resource',
+      });
+
+      // THEN
+      const metadata = res.node.metadata.find(m => m.type === cxschema.ArtifactMetadataEntryType.LOGICAL_ID);
+      expect(metadata).toBeDefined();
+      expect(metadata?.trace).toBeDefined();
+      expect(metadata?.trace?.length).toBeGreaterThan(0);
+    } finally {
+      delete process.env.CDK_DEBUG;
+    }
+  });
 });