Add failing test demonstrating missing $dynamicRef support (Draft 2020-12)

[Anshikakalpana]

Summary

$dynamicRef is currently not supported in vscode-json-languageservice. This issue tracks incremental progress toward supporting it, starting with a failing test that documents the expected behavior.

This leads to valid Draft 2020-12 schemas being rejected during validation.

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Current Behavior

Schemas using $dynamicRef produce the warning:

"The schema uses meta-schema features ($dynamicRef) that are not yet supported by the validator."

Validation does not proceed correctly.

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Expected Behavior

For same-schema $dynamicRef (i.e., referencing a $dynamicAnchor within the same schema and without dynamic scope extension), validation should proceed without reporting an unsupported feature.

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Minimal Repro

Schema:

{
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "$dynamicAnchor": "node",
  "type": "object",
  "properties": {
    "child": {
      "$dynamicRef": "#node"
    }
  }
}

Data:

{
  "child": {}
}

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Root Cause

In jsonSchemaService.ts, $dynamicRef is detected and added to usesUnsupportedFeatures with no attempt to resolve it:

if (next.$dynamicRef) {
    usesUnsupportedFeatures.add('$dynamicRef');
}

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Additional Context

I added a failing test demonstrating this behavior — 58 existing tests pass, 1 new test fails due to $dynamicRef being treated as unsupported.

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Impact

This affects real-world usage of Draft 2020-12 schemas. Tools using modern JSON Schema features (e.g., MCP integrations) fail validation entirely due to $dynamicRef being unsupported.

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Related Issues

• [json] support meta-schema features vscode#155379
• Support JSON schema draft 2020-12 vscode#251315
• [MCP Server] Tools have invalid JSON schemas in VS Code due to Draft 2020-12 $dynamicRef usage directus/directus#25906

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Next Steps

I have a failing test ready and have been exploring approaches for resolution. Happy to open a PR and discuss the right direction with maintainers — wanted to check in here first before proceeding.