Validation fails to fail on missing required inner field

[musteresel]

Initially reported here: xpol/lua-rapidjson#63

This happens in an Alpine Docker container:

$ apk list rapidjson
rapidjson-1.1.0-r8 x86_64 {rapidjson} (MIT) [installed]
$ apk list rapidjson-dev
rapidjson-dev-1.1.0-r8 x86_64 {rapidjson} (MIT) [installed]
$ apk list g++
g++-14.2.0-r6 x86_64 {gcc} (GPL-2.0-or-later AND LGPL-2.1-or-later) [installed]
$ g++ rj-test.cc -o rj-test && ./rj-test # Code to reproduce, see below
Accepted!

I have an "outer" array, which has "inner" objects, which need to have a "num" field.

JSON Schema:

{
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "title": "Demo",
  "type": "object",
  "properties": {
    "outer": {
      "type": "array",
      "items": {
        "$ref": "#/$defs/inner"
      }
    }
  },
  "required": ["outer"],
  "additionalProperties": false,
  "$defs": {
    "inner": {
      "type": "object",
      "properties": {
        "num": {
          "type": "number"
        }
      },
      "required": ["num"],
      "additionalProperties": false
    }
  }
}

JSON:

{
  "outer": [
    {
    }
  ]
}

Expected: Failing validation because "num" is missing, this happens for example with this online validator: https://www.jsonschemavalidator.net/
Outcome: Validation succeeds.

Code to reproduce:

#include "rapidjson/schema.h"
#include "rapidjson/stringbuffer.h"
#include <cstdio>

char const *schemaJson = R"({
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "title": "Demo",
  "type": "object",
  "properties": {
    "outer": {
      "type": "array",
      "items": {
        "$ref": "#/$defs/inner"
      }
    }
  },
  "required": ["outer"],
  "additionalProperties": false,
  "$defs": {
    "inner": {
      "type": "object",
      "properties": {
        "num": {
          "type": "number"
        }
      },
      "required": ["num"],
      "additionalProperties": false
    }
  }
})";

char const *inputJson = R"(
{
  "outer": [
    {
    }
  ]
}
)";

int main()
{
    rapidjson::Document sd;
    if (sd.Parse(schemaJson).HasParseError())
    {
        size_t const offset = sd.GetErrorOffset();
        printf("Failed parsing schema: %d %zu %s\n", sd.GetParseError(), offset, schemaJson + offset);
        return 1;
    }
    rapidjson::SchemaDocument schema(sd);

    rapidjson::Document d;
    if (d.Parse(inputJson).HasParseError())
    {
        size_t const offset = d.GetErrorOffset();
        printf("Failed parsing json: %d %zu %s\n", d.GetParseError(), offset, inputJson + offset);
        return 1;
    }

    rapidjson::SchemaValidator validator(schema);
    if (!d.Accept(validator))
    {
        rapidjson::StringBuffer sb;
        validator.GetInvalidSchemaPointer().StringifyUriFragment(sb);
        printf("Invalid schema: %s\n", sb.GetString());
        printf("Invalid keyword: %s\n", validator.GetInvalidSchemaKeyword());
        sb.Clear();
        validator.GetInvalidDocumentPointer().StringifyUriFragment(sb);
        printf("Invalid document: %s\n", sb.GetString());
    }
    else
    {
        printf("Accepted!\n");
    }
}

[musteresel]

This seems to be related to the usage of $ref, because here it fails as expected:

char const *schemaJson = R"({
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "title": "Demo",
  "type": "object",
  "properties": {
    "outer": {
      "type": "array",
      "items": {


      "type": "object",
      "properties": {
        "num": {
          "type": "number"
        }
      },
      "required": ["num"],
      "additionalProperties": false


      }
    }
  },
  "required": ["outer"],
  "additionalProperties": false
})";