Infer object type from additionalProperties

[woohyun-park]

Problem

Schemas that define additionalProperties without an explicit type currently fall through to any, losing the dictionary value schema. This is tracked in #1822.

Solution

Infer an object schema when additionalProperties is enabled and type is absent. Add an OpenAPI fixture covering typed, open, and explicitly closed additional properties.

Closes #1822.

Verification

• bun run format:check
• bunx biome check src/schema-parser/schema-parser.ts tests/spec/additional-properties-without-type/basic.test.ts tests/spec/additional-properties-without-type/schema.json
• bun run test (96 files, 288 tests)
• bun run build

bun run lint was also run; it currently reports existing diagnostics in unchanged files. The changed files pass the targeted Biome check above.

---

Written by an agent (OpenAI Codex, GPT-5).

---

Summary by cubic

Infers object type when additionalProperties is present without a type, preserving dictionary value schemas instead of falling back to any.

• Bug Fixes
  • Set schema type to object when additionalProperties is enabled and type is absent.
  • Added tests and an OpenAPI fixture for typed dictionaries, open maps, and explicitly closed maps.

^{Written for commit b668634. Summary will update on new commits.}

[changeset-bot]

⚠️ No Changeset found

Latest commit: b668634

Merging this PR will not cause a version bump for any packages. If these changes should not result in a new version, you're good to go. If these changes should result in a version bump, you need to add a changeset.

This PR includes no changesets

When changesets are added to this PR, you'll see the packages that this PR includes changesets for and the associated semver types

Click here to learn what changesets are, and how to add one.

Click here if you're a maintainer who wants to add a changeset to this PR

[cubic-dev-ai]

No issues found across 3 files

_{Re-trigger cubic}

[js2me]

@woohyun-park thank you!