fix(cloudformation-include): string arrays inside unknown properties cannot be parsed (#32461)

We are using `this` to refer to static methods, which fails at runtime. Use the class name instead.

Fixes #32454.

----

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

Author: otaviomacedo

packages/aws-cdk-lib/cloudformation-include/test/test-templates/string-arrays-in-policy.json

@@ -0,0 +1,32 @@
+{
+  "AWSTemplateFormatVersion": "2010-09-09",
+  "Resources": {
+    "AutoScalingGroup": {
+      "Type": "AWS::AutoScaling::AutoScalingGroup",
+      "Properties": {
+        "DesiredCapacity": "1",
+        "MinSize": "1",
+        "MaxSize": "5"
+      },
+      "CreationPolicy": {
+        "ResourceSignal": {
+          "Count": 1,
+          "Timeout": "PT10M"
+        }
+      },
+      "UpdatePolicy": {
+        "AutoScalingRollingUpdate": {
+          "PauseTime": "PT10M",
+          "SuspendProcesses": [
+            "HealthCheck",
+            "ReplaceUnhealthy",
+            "AZRebalance",
+            "AlarmNotification",
+            "ScheduledActions"
+          ],
+          "WaitOnResourceSignals": true
+        }
+      }
+    }
+  }
+}

packages/aws-cdk-lib/cloudformation-include/test/valid-templates.test.ts

@@ -714,6 +714,13 @@ describe('CDK Include', () => {
     );
   });
 
+  test('correctly handles string arrays in policy attributes', () => {
+    const cfnTemplate = includeTestTemplate(stack, 'string-arrays-in-policy.json');
+    Template.fromStack(stack).templateMatches(
+      loadTestFileToJsObject('string-arrays-in-policy.json'),
+    );
+  });
+
   test("correctly handles referencing the ingested template's resources across Stacks", () => {
     // for cross-stack sharing to work, we need an App
     const app = new core.App();

packages/aws-cdk-lib/core/lib/helpers-internal/cfn-parse.ts

@@ -173,7 +173,7 @@ export class FromCloudFormation {
     }
 
     // in all other cases, delegate to the standard mapping logic
-    return this.getArray(this.getString)(value);
+    return FromCloudFormation.getArray(FromCloudFormation.getString)(value);
   }
 
   public static getArray<T>(mapper: (arg: any) => FromCloudFormationResult<T>): (x: any) => FromCloudFormationResult<T[]> {
@@ -716,8 +716,8 @@ export class CfnParser {
 
     const key = objectKeys[0];
     return key === 'Ref' || key.startsWith('Fn::') ||
-        // special intrinsic only available in the 'Conditions' section
-        (this.options.context === CfnParsingContext.CONDITIONS && key === 'Condition')
+    // special intrinsic only available in the 'Conditions' section
+    (this.options.context === CfnParsingContext.CONDITIONS && key === 'Condition')
       ? key
       : undefined;
   }