[Bug] oneOf and empty-string

[leberknecht]

Hi, im struggling with a field that should either have a date or an empty string:

from jsonschema import validate

schema = {
    "$schema": "http://json-schema.org/draft-07/schema#",
    "type": "array",
    "items": {
        "$ref": "#/definitions/MyElement"
    },
    "definitions": {
        "MyElement": {
            "type": "object",
            "properties": {
                "my_date": { "$ref": "#/definitions/MaybeDate" },
            }
        },
        "MaybeDate": {
            "title": "MaybeDate",
            "oneOf": [{
                "type": "string",
                "format": "date"
            }, {
                "const": ""
            }]
        }
    }
}

data = [{
    "my_date": "2018-05-05",
}]

validate(data, schema)

data = [{
    "my_date": "",
}]

validate(data, schema)

Both should be valid, but the empty-string causes

Traceback (most recent call last):
  File "config/scratches/scratch_25.py", line 38, in <module>
    validate(data, schema)
  File "/venv/lib/python3.6/site-packages/jsonschema/validators.py", line 899, in validate
    raise error
jsonschema.exceptions.ValidationError: '' is valid under each of {'const': ''}, {'type': 'string', 'format': 'date'}

Failed validating 'oneOf' in schema['items']['properties']['my_date']:
    {'oneOf': [{'format': 'date', 'type': 'string'}, {'const': ''}],
     'title': 'MaybeDate'}

On instance[0]['my_date']:

This does not happen on https://www.jsonschemavalidator.net/ nor using the nodejs module https://www.npmjs.com/package/jsonschema
Am i missing something?
Using v3.0.1

[Julian]

You didn't pass in a format checker.

…

On Wed, Jul 17, 2019, 08:35 Delf Tonder ***@***.***> wrote: Hi, im struggling with a field that should either have a date or an empty string: from jsonschema import validate schema = { "$schema": "http://json-schema.org/draft-07/schema#", "type": "array", "items": { "$ref": "#/definitions/MyElement" }, "definitions": { "MyElement": { "type": "object", "properties": { "my_date": { "$ref": "#/definitions/MaybeDate" }, } }, "MaybeDate": { "title": "MaybeDate", "oneOf": [{ "type": "string", "format": "date" }, { "const": "" }] } } } data = [{ "my_date": "2018-05-05", }] validate(data, schema) data = [{ "my_date": "", }] validate(data, schema) Both should be valid, but the empty-string causes Traceback (most recent call last): File "config/scratches/scratch_25.py", line 38, in <module> validate(data, schema) File "/venv/lib/python3.6/site-packages/jsonschema/validators.py", line 899, in validate raise error jsonschema.exceptions.ValidationError: '' is valid under each of {'const': ''}, {'type': 'string', 'format': 'date'} Failed validating 'oneOf' in schema['items']['properties']['my_date']: {'oneOf': [{'format': 'date', 'type': 'string'}, {'const': ''}], 'title': 'MaybeDate'} On instance[0]['my_date']: This does not happen on https://www.jsonschemavalidator.net/ nor using the nodejs module https://www.npmjs.com/package/jsonschema Am i missing something? Using v3.0.1 — You are receiving this because you are subscribed to this thread. Reply to this email directly, view it on GitHub <#585>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AACQQXTNGLRR7N3KEUPRAJDP74GXPANCNFSM4IEP3TWQ> .

[leberknecht]

Indeed, changing it to

from jsonschema import FormatChecker
[...]
validate(data, schema, format_checker=FormatChecker())

solved it :) Thank you!