Top-level $ref in 0.44.0

[joshkel]

When I upgraded from typescript-json-schema 0.43.0 to 0.44.0, I noticed that AJV started giving a new warning when compiling the generated schema:

$ref: keywords ignored in schema at path "#/properties/data/properties/pcList"

Sample TypeScript types:

interface Parent { name?: string; children: Child[]; }
interface Child { name?: string; parent?: Parent; }

The generated schema in 0.43.0 has a definitions.Parent section and also duplicates the Parent type's properties on the root schema. The generated schema in 0.44.0 has a top-level "$ref": "#/definitions/Parent" property. If I understand the discussions at ajv-validator/ajv#1121 correctly, the top-level $ref object is technically invalid.

If I've misunderstood this, please let me know. Thanks!

[domoritz]

Hmm. Is this and instance of the problem? If so, we may need to revert the pull request.

[joshkel]

From doing some local experiments, I apparently had misunderstood; it looks like a top-level $ref can be valid; the fact that type is still there (like you said) is what's causing the problem.

I manually removed the top-level type from a sample recursive schema, and I'm able to compile and use it in AJV without errors.

[domoritz]

@darkowic and @joshkel do you think you can look into a fix for this bug?

[joshkel]

@domoritz, I took a stab at fixing it in #392. Feedback welcome; I'm pretty new to JSON Schema and may have missed something.