aws-cdk-lib/core: cfn-parse cannot parse CfnInclude template

[mikevoets]

Describe the bug

We have a cloudformation template for autoscaling that we import into our CDK stack with CfnInclude.

I believe that #32321 that was released in aws-cdk-lib@2.172.0 last week broke the parsing of this template, because we now get an error when we synthesize this stack. In aws-cdk-lib@2.171.0, the synthesization works without any errors thrown.

Regression Issue

• Select this option if this issue appears to be a regression.

Last Known Working CDK Version

2.171.0

Expected Behavior

The stack synthesization is successful and runs without errors.

Current Behavior

The stack synthesization fails with:

TypeError: Cannot read properties of undefined (reading 'getArray')
    at getStringArray (/Users/path/to/repo/node_modules/aws-cdk-lib/core/lib/helpers-internal/cfn-parse.js:1:3237)
    at ObjectParser.parse (/Users/path/to/repo/node_modules/aws-cdk-lib/core/lib/helpers-internal/cfn-parse.js:1:18595)
    at ObjectParser.parseCase (/Users/path/to/repo/node_modules/aws-cdk-lib/core/lib/helpers-internal/cfn-parse.js:1:18475)
    at parseAutoScalingRollingUpdate (/Users/path/to/repo/node_modules/aws-cdk-lib/core/lib/helpers-internal/cfn-parse.js:1:8738)
    at ObjectParser.parse (/Users/path/to/repo/node_modules/aws-cdk-lib/core/lib/helpers-internal/cfn-parse.js:1:18595)
    at ObjectParser.parseCase (/Users/path/to/repo/node_modules/aws-cdk-lib/core/lib/helpers-internal/cfn-parse.js:1:18475)
    at CfnParser.parseUpdatePolicy (/Users/path/to/repo/node_modules/aws-cdk-lib/core/lib/helpers-internal/cfn-parse.js:1:7642)
    at CfnParser.handleAttributes (/Users/path/to/repo/node_modules/aws-cdk-lib/core/lib/helpers-internal/cfn-parse.js:1:4944)
    at Function._fromCloudFormation (/Users/path/to/repo/node_modules/aws-cdk-lib/aws-autoscaling/lib/autoscaling.generated.js:1:1188)
    at CfnInclude.getOrCreateResource (/Users/path/to/repo/node_modules/aws-cdk-lib/cloudformation-include/lib/cfn-include.js:1:14510)
Subprocess exited with error 1

Reproduction Steps

Given the following code:

template.yaml

---
AWSTemplateFormatVersion: '2010-09-09'
Resources:
  AutoScalingGroup:
    Type: 'AWS::AutoScaling::AutoScalingGroup'
    Properties:
      DesiredCapacity: 1
      MaxSize: 1
      MinSize: 1
    CreationPolicy:
      ResourceSignal:
        Count: 1
        Timeout: PT10M
    UpdatePolicy:
      AutoScalingRollingUpdate:
        PauseTime: PT10M
        SuspendProcesses:
          - HealthCheck
          - ReplaceUnhealthy
          - AZRebalance
          - AlarmNotification
          - ScheduledActions
        WaitOnResourceSignals: true

app.ts

import * as cdk from 'aws-cdk-lib';
import { CfnInclude } from 'aws-cdk-lib/cloudformation-include';
import { Construct } from 'constructs';

class TestStack extends cdk.Stack {
  constructor(scope: Construct, id: string, props?: cdk.StackProps) {
    super(scope, id, props);

    new CfnInclude(this, 'Template', {
      templateFile: './template.yaml',
    });
  }
}

const app = new cdk.App();

new TestStack(app, 'TestStack', {
  env: {
    region: process.env.AWS_REGION,
    account: process.env.AWS_ACCOUNT,
  },
});

Run:

npm run cdk -- -a "npx ts-node --prefer-ts-exts app.ts" synth TestStack

Possible Solution

No response

Additional Information/Context

No response

CDK CLI Version

2.172.0 (build 0f666c5)

Framework Version

No response

Node.js Version

v22.10.0

OS

macOS 15.1.1 (24B91)

Language

TypeScript

Language Version

TypeScript (5.7.2)

Other information

No response

[khushail]

@mikevoets , thanks for reporting this and sharing the repro code. I am able to reproduce the issue and can see that with CDK Version 2.172.0 , this error is being shown-

while it works fine in earlier CDK Version 2.171.0.

Reaching out to Core team and marking as appropriate.