Fix invalid empty required: [] in OpenAPI schema generation

[Copilot]

Typia was generating required: [] in OpenAPI schemas, which violates both OpenAPI and JSON Schema specifications. Per OpenAPI spec: "An empty list required: [] is not valid. If all properties are optional, do not specify the required keyword."

Changes

• src/programmers/internal/json_schema_object.ts: Conditionally include required only when non-empty
• src/programmers/internal/json_schema_native.ts: Remove hardcoded required: []
• src/programmers/llm/LlmApplicationProgrammer.ts: Remove hardcoded required: []
• test/schemas/**/*.json: Updated 184 test schema expectations

Before/After

interface ExampleInterface {
    a?: number;
    b?: string;
}
const schema = typia.json.schema<ExampleInterface>();

// Before: { type: "object", properties: {...}, required: [] }  ❌
// After:  { type: "object", properties: {...} }                ✅

Testing

npm run build
npm run test

All tests pass.

Original prompt

---

This section details on the original issue you should resolve

<issue_title>[Bug] Invalid OpenAPI Schema is generated in specific situations.</issue_title>
<issue_description>## 🐛 Bug Report

📝 Summary

An invalid OpenAPI schema is generated in specific situations.

• Typia Version: 10.1.0
• Expected behavior:
  Typia should not generate an empty array for the required field in OpenAPI schemas. According to the OpenAPI and JSON Schema specifications, an empty required array is invalid.
• Actual behavior:
  Typia generates a schema that includes an empty required array (required: []) in certain cases.

Details

According to the OpenAPI specification, an empty array for the required field is not allowed.

This can be verified in the following references:

1. OpenAPI Specification – Data Types

   An empty list required: [] is not valid. If all properties are optional, do not specify the required keyword.

2. JSON Schema Draft-04
   See the definitions.stringarray section.

Both OpenAPI and its underlying JSON Schema Draft-04 specification disallow an empty required array.

However, Typia generates such an invalid schema in specific cases, for example:

https://typia.io/playground/?script=JYWwDg9gTgLgBDAnmYBDANHA3g1BzAZzgF84AzKCEOAIiRVRoG4AoFgUwA9JY5gA7GOyhlUAY3ZwASqgDuANVQAbAK7sAYpRABRfgDdsLOMbhQ5i1Rq0AuaezHQAJgB4CMKALyZU-RAD5WYjYHfjc4AjEAC3YQVDgAXgRkNAA6ACsCCH4UiOjY5xkFZTVNKl09PwAKAEpWFhDMpXYUpQg8StyY1FqWIA

This behavior is likely a bug.

Thank you.

</issue_description>

Comments on the Issue (you are @copilot in this section)

• Fixes [Bug] Invalid OpenAPI Schema is generated in specific situations. #1695

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[socket-security]

Review the following changes in direct dependencies. Learn more about Socket for GitHub.

Diff	Package	Supply Chain Security	Vulnerability	Quality	Maintenance	License
	@​types/​body-parser@​1.19.5 ⏵ 1.19.6
	@​types/​express@​4.17.21 ⏵ 4.17.25
	@​typescript-eslint/​parser@​8.30.1 ⏵ 8.48.0
	@​types/​autocannon@​7.12.6 ⏵ 7.12.7	+1		+1
	@​types/​inquirer@​8.2.10 ⏵ 8.2.12
	tinyglobby@​0.2.13 ⏵ 0.2.15			-14
	@​typescript-eslint/​eslint-plugin@​8.30.1 ⏵ 8.48.0	+1		+1
	@​types/​node@​22.14.1 ⏵ 18.19.130
	@​types/​node@​22.14.1 ⏵ 20.19.25
	@​types/​node@​22.14.1 ⏵ 22.19.1	+1		+1
	fp-ts@​2.16.10 ⏵ 2.16.11				+2
	comment-json@​4.2.5 ⏵ 4.4.1	+1		+1
	prettier-plugin-jsdoc@​1.3.3 ⏵ 1.5.0	+1			+7
	rollup-plugin-node-externals@​8.0.0 ⏵ 8.1.2
	class-validator@​0.14.1 ⏵ 0.14.3			+1
	fastify@​4.29.0 ⏵ 4.29.1	+1	+22
	prettier@​3.5.3 ⏵ 3.6.2	+1
	zod@​3.24.3 ⏵ 3.25.76	+1
	inquirer@​8.2.6 ⏵ 8.2.7
	rollup@​4.40.0 ⏵ 4.53.3				-1
	openai@​4.95.1 ⏵ 4.104.0	+1		+1	-1

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npm i https://pkg.pr.new/typia@1696

commit: a3e028f