fix(core): isTaggable function can return undefined instead of false

[sumupitchayan]

Closes #26495

Reason for this change

The isTaggable function of the TagManager class is currently broken in Python, as it can return undefined instead of true or false.

Description of changes

In JS/TS, the logical AND operator (&&) returns the first falsy value it encounters, even if that value is undefined instead of false - so the current implementation of isTaggable allows for undefined to be returned if tags is undefined:

public static isTaggable(construct: any): construct is ITaggable {
  const tags = (construct as any).tags;
  return tags && typeof tags === 'object' && (tags as any)[TAG_MANAGER_SYM];
}

The fix is simply changing the return line to the following to handle cases where tags is null or undefined:

return tags !== undefined && tags !== null && typeof tags === 'object' && (tags as any)[TAG_MANAGER_SYM];

Description of how you validated changes

Added a unit test to assert that isTaggable returns false, not undefined for a non-taggable Construct (and still returns true for a taggable construct).

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

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[rix0rrr]

But this now explodes if tags is null. It shouldn't be, but it could be.

Sillily, in JS it's:

typeof null == 'object'

So you can't really get away from the truthiness test. The only thing you have to do is make sure the truth-tested falsy value doesn't leak through.

[sumupitchayan]

Good to know - just updated the return statement:

return tags !== undefined && tags !== null && ...

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• CodeBuild project: AutoBuildv2Project1C6BFA3F-wQm2hXv2jqQv
• Commit ID: d1c727b
• Result: SUCCEEDED
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