Support $ref and $defs in JSON Schema

[eiixy]

This PR implements $ref and $defs support in the JSON Schema validator.
Key features include:

• Resolves $ref references recursively.
• Supports nested $defs and path resolution.

[codecov]

Codecov Report

Attention: Patch coverage is 90.76923% with 6 lines in your changes missing coverage. Please review.

Project coverage is 86.30%. Comparing base (c125ae2) to head (b1e53c7).
Report is 3 commits behind head on master.

Files with missing lines	Patch %	Lines
jsonschema/json.go	72.72%	4 Missing and 2 partials ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #1030      +/-   ##
==========================================
+ Coverage   85.83%   86.30%   +0.46%     
==========================================
  Files          43       43              
  Lines        2316     2387      +71     
==========================================
+ Hits         1988     2060      +72     
+ Misses        305      302       -3     
- Partials       23       25       +2     

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[sashabaranov]

Wow, this is super cool! Thanks!

[Copilot]

Pull Request Overview

This PR adds full support for $ref and $defs resolution to the JSON Schema validator, updates schema generation to emit reusable definitions, and extends tests accordingly.

• Implements CollectDefs to gather all $defs into a map for lookup
• Updates Validate and VerifySchemaAndUnmarshal to accept and use resolved definitions
• Enhances GenerateSchemaForType and reflection logic to emit $ref for named structs and populate $defs
• Adds tests for reference resolution, $defs collection, and schema generation with $ref/$defs

Reviewed Changes

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

File	Description
jsonschema/validate.go	Added CollectDefs, extended Validate to handle $ref, and updated VerifySchemaAndUnmarshal to wire in definitions
jsonschema/validate_test.go	Added tests for recursive $ref validation and CollectDefs functionality
jsonschema/json.go	Extended GenerateSchemaForType and reflection routines to emit $ref/$defs
jsonschema/json_test.go	Added schema-generation test verifying $ref and $defs output

Comments suppressed due to low confidence (1)

jsonschema/validate.go:37

• Unmarshalling into &v writes into the local interface variable rather than the caller’s target. Change this to json.Unmarshal(content, v) so the provided pointer is populated correctly.

	return json.Unmarshal(content, &v)

[sashabaranov]

@eiixy seems like this PR broke an integration test https://github.com/sashabaranov/go-openai/actions/runs/16192799414/job/45712241252

[eiixy]

@eiixy seems like this PR broke an integration test https://github.com/sashabaranov/go-openai/actions/runs/16192799414/job/45712241252

The issue is that using a $ref on the root schema (in a JSON Schema parsing/validation context) breaks proper subschema resolution. I’ll fix this later today—removing the root $ref and updating the parser/validator to align with standard reference resolution.