feat(core): allow indentation suppression in nested stacks

[jdebuseamazon]

Issue # (if applicable)

Closes #32798

Reason for this change

Stacks can be created with an optional suppressTemplateIndentation parameter to determine whether indentation is suppressed. This may for example be useful to keep stack sizes within AWS CloudFormation quotas. However, indentation suppression is currently not supported for nested stacks.

Description of changes

A new suppressTemplateIndentation parameter, based on the Stack suppressTemplateIndentation was added to NestedStackProps. The new parameter was added to the call to the superclass constructor within the NestedStack constructor:

  constructor(scope: Construct, id: string, props: NestedStackProps = { }) {
    const parentStack = findParentStack(scope);

    super(scope, id, {
      env: { account: parentStack.account, region: parentStack.region },
      synthesizer: new NestedStackSynthesizer(parentStack.synthesizer),
      description: props.description,
      crossRegionReferences: parentStack._crossRegionReferences,
      suppressTemplateIndentation: props.suppressTemplateIndentation,
    });

Description of how you validated changes

Unit tests and an integration test. The integration test was based on the existing integ.nested-stack-references.ts.

Checklist

• My code adheres to the CONTRIBUTING GUIDE and DESIGN GUIDELINES

---

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

[aws-cdk-automation]

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[fossamagna]

Why is this PR still sitting here without review?
I wait to merged this PR.

[fossamagna]

Hi @otaviomacedo @kaizencc

I’m sorry to bother you, but I’d like to ask for a review on this PR.

This change addresses the nested stack template size issue discussed in #32798 by allowing
suppressTemplateIndentation to be propagated via NestedStackProps.
This is a blocking issue for us in real-world usage, as we are hitting the 1MB template size limit
when using nested stacks.

I understand this PR has been inactive for a while.
If this approach is not preferred or the PR is considered outdated, I’m very happy to:

• rebase it onto the latest main, or
• open a fresh PR that supersedes this one, or
• make any changes you’d recommend to move this forward.

Any guidance on the preferred next step (or the right reviewers) would be greatly appreciated.

[go-to-k]

Thanks for this PR. Left a minor comment.

[go-to-k]

This test doesn't need to be a reference test for nested stacks.

Also, suppressTemplateIndentation property does not appear on the CFn template, so it would be better to check in assertions whether template indentation is suppressed.

It should be able to be simplified as follows. (In that case, the filename would be changed too.)

For example:

const app = new cdk.App();
const stack = new cdk.Stack(app, 'ParentStack');

const nested = new cdk.NestedStack(stack, 'NestedSuppressIndentation', { suppressTemplateIndentation: true });
new s3.Bucket(nested, 'Bucket'); // dummy

const testCase = new integ.IntegTest(app, 'NestedSuppressIndentationTest', {
  testCases: [stack],
});

const nestedChild = nested.node.defaultChild as cdk.CfnStack;
const nestedTemplateUrl = nestedChild.templateUrl!; // Nested stacks must have the templateUrl

const apiCall = testCase.assertions.awsApiCall('S3', 'getObject', {
  Bucket: cdk.Fn.select(3, cdk.Fn.split('/', nestedTemplateUrl)),
  Key: cdk.Fn.select(4, cdk.Fn.split('/', nestedTemplateUrl)),
});

apiCall.expect(integ.ExpectedResult.objectLike({ Body: '{"Resources":{"Bucket83908E77":{"Type":"AWS::S3::Bucket","UpdateReplacePolicy":"Retain","DeletionPolicy":"Retain"}}}' }));

[jdebuseamazon]

Thanks for the comment, I've updated the test per your suggestions

[github-actions]

⚠️ Experimental Feature: This security report is currently in experimental phase. Results may include false positives and the rules are being actively refined.
Please try merge from main to avoid findings unrelated to the PR.

---

	Tests	Passed ✅	Skipped	Failed
Security Guardian Results	72 ran	72 passed

Test	Result
No test annotations available

• View Security Guardian Results

[github-actions]

⚠️ Experimental Feature: This security report is currently in experimental phase. Results may include false positives and the rules are being actively refined.
Please try merge from main to avoid findings unrelated to the PR.

---

	Tests	Passed ✅	Skipped	Failed
Security Guardian Results with resolved templates	72 ran	72 passed

Test	Result
No test annotations available

• View Security Guardian Results with resolved templates

[go-to-k]

Thanks for the change! LGTM.

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Required conditions to merge

• #approved-reviews-by >= 1 [🛡 GitHub branch protection]
  • feat(core): allow indentation suppression in nested stacks #35122
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  • feat(core): allow indentation suppression in nested stacks #35122
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