fix: avoid incorrect additionalProperties for Pick<..., AliasLiteralUnion>

[alexchexes]

Closes #2229

Version

Published prerelease version: v2.4.1-next.0

Changelog

🎉 This release contains work from a new contributor! 🎉

Thank you, null@alexchexes, for all your work!

🐛 Bug Fix

• fix: avoid incorrect additionalProperties for Pick<..., AliasLiteralUnion> #2230 (@alexchexes)

🔩 Dependency Updates

• chore(deps-dev): bump @types/node from 22.14.0 to 22.14.1 #2225 (@dependabot[bot])
• chore(deps-dev): bump typescript-eslint from 8.29.0 to 8.29.1 #2226 (@dependabot[bot])
• chore(deps-dev): bump eslint-config-prettier from 10.1.1 to 10.1.2 #2227 (@dependabot[bot])
• chore(deps-dev): bump eslint from 9.23.0 to 9.24.0 #2228 (@dependabot[bot])

Authors: 2

• @alexchexes
• @dependabot[bot]

[alexchexes]

The issue is not fully resolved yet. Turns out the fix does not cover all union key types. Investigating

[Copilot]

Copilot reviewed 3 out of 4 changed files in this pull request and generated no comments.

Files not reviewed (1)

• test/valid-data/type-mapped-pick-union-alias/schema.json: Language not supported

Comments suppressed due to low confidence (1)

src/NodeParser/MappedTypeNodeParser.ts:161

• [nitpick] Consider adding an inline comment to clarify why dereferencing with derefType is necessary here, to help future maintainers understand this filtering logic.

const key = keyListType.getTypes().filter((type) => !(derefType(type) instanceof LiteralType))[0];

[arthurfiorette]

If you want, we can merge this PR as is and open another one with the proper fix :)

[alexchexes]

I don't mind, let's merge this one as a first step

[alexchexes]

Just to clarify what's not covered in this PR: the fix only dereferences the top-level union keys, but not nested aliases.

For example:

SomeInterface {
  a: number;
  b: string;
  c: boolean;
}

type AB = "a" | "b";
type C = "c";

export type Test = Pick<SomeInterface, AB | C>;

still produces unexpected "additionalProperties"

[arthurfiorette]

I created the new issue so we can keep track of it. @alexchexes, would you like to work on it, too?

[github-actions]

🚀 PR was released in v2.4.1-next.0 🚀

[alexchexes]

Yep, already in progress.
Thanks!