minProperties constraint ignored when using definitions/references in JSON schema

I have a JSON schema that defines a type language_object with some properties and then uses that on one of the fields, along with a minProperties constraint.

However, when validating against this schema, submitting an empty object in said field does not raise a ValidationException. It appears that the minProperties constraint is ignored when it is placed alongside $ref

I have prepared a schema that defines my field once as name using references and once as nameEx with explicit properties. As far as I can tell these should be equivalent:

{
    "type":"object",
    "$schema":"http://json-schema.org/draft-04/schema#",
    "definitions":{
        "language_object":{
            "type":"object",
            "additionalProperties":false,
            "patternProperties":{
                "^[a-z]{2}$":{
                    "type":"string"
                }
            }
        }
    },
    "properties":{
        "name":{
            "$ref":"#/definitions/language_object",
            "minProperties":1
        },
        "nameEx":{
            "type":"object",
            "patternProperties":{
                "^[a-z]{2}$":{
                    "type":"string"
                }
            },
            "additionalProperties":false,
            "minProperties":1
        },
        "date":{
            "type":"string",
            "format":"date-time"
        }
    }
}

When I validate the following JSON

{
   "name":{},
    "nameEx":{}
}

I only get #/nameEx: minimum size: [1], found: [0], not both. Other situations, like this disallowed key/property work fine on both:

{
   "name":{"nbb":"bla"},
   "nameEx":{"nbb":"bla"}
}

Returns

#: 2 schema violations found
#/nameEx: extraneous key [nbb] is not permitted
#/name: extraneous key [nbb] is not permitted

Thank you for your patience!

[Antares42]

Thanks, I followed the discussions in the comments. You are awesome.

[erosb]

@Antares42 version 1.2.0 is available on maven central with the bugfix (also with “format” support)