Regex validation for pattern is ignored or incorrect with this regex

[pasanbox]

I'm using the same example from examples/schemavalidator.cpp.

My schema:

{
  "$schema": "http://json-schema.org/draft-04/schema#",
  "type": "object",
  "title": "SampleMessage",
  "properties": {
    "id": {
      "type": "string"
    },
    "regexfield": {
      "type": "string",
      "pattern": "^[\\x00-\\x7F]*$"
    },
    "status": {
      "type": "string",
      "enum": [
        "VALID",
        "INVALID"
      ]
    }
  },
  "required": [
    "regexfield",
    "status"
  ]
}

My message;

{
  "id": "w10ooe",
  "regexfield": "w10ooe¼",
  "status": "VALID"
}

Expected result:

validation fail for pattern

Actual result

Input JSON is valid.

As you can see, the pattern is for validating if the regexfield contains only ASCII characters. However, the validation returns successful even when the field has a non-ascii value. The same regex gives expected result when checking with regex101.com.

[smhdfdl]

@pasanbox This comment might explain what you are seeing? https://github.com/Tencent/rapidjson/pull/1915#issuecomment-890048964