Error in early release 3.0.0.a3 but not in 2.6.0

[timbouffard]

I'm sure I'm just doing something wrong but in version 2.6.0 this code works for both validation calls. In the newer version the second validation call fails.

#!/usr/bin/env python
# -*- coding: utf-8 -*-

import jsonschema
from jsonschema import validate, Draft4Validator
from jsonschema.exceptions import ValidationError


def main():
    # Define JSON schema
    schema = {
        'type': 'object',
        'properties': {
            'value': {
                'type': 'number'
            },
        }
    }

    all_validators = dict(Draft4Validator.VALIDATORS)

    MyValidator = jsonschema.validators.create(
        meta_schema=Draft4Validator.META_SCHEMA,
        validators=all_validators
    )

    print('my validator')
    # This call to validate 'works', I get a validation error
    try:
        print(validate({'value': 'a'}, schema))
    except ValidationError:
        print('validation error when calling validate')

    # this call to my_validator.is_valid fails...it doesn't return false, it just errors
    my_validator = MyValidator(schema)
    print(my_validator.is_valid({'value': 'a'}))


if __name__ == '__main__':
    main()

This is python 3.6 if that makes any difference. I tried it for 3.0.0.a3, a2 and a1 - same error.
Product is awesome btw. Very helpful with what I need to do.

[Julian]

Hm, my response didn't seem to come through here, so typing it out again (fingers crossed GitHub):

I'd guess this likely has to do with the type checker interface changes.

Though if so, thanks for filing this, maybe it's a nudge to change the interface slightly more.

Though overall, unless you have a good reason for doing it in your real code, not sure why you're using create rather than extend.

And thanks! Glad it's helping you.

[timbouffard]

Ah okay. I'll try extend. I was basically following the example at this link because I wanted to have a custom check on a particular number. Then the example I included here was a stripped down example.

[Julian]

Bit of a shame that link became a blog post instead of just a pull request adding some prose docs for those cases, would have been happy to merge something like it.

Who knows if it's correct :), will have to read through it, but yeah I suspect that you likely do want extend.

[timbouffard]

Using extend worked perfectly. From the above sample I changed MyValidator to:

    MyValidator = jsonschema.validators.extend(validator=Draft4Validator,
                                               validators=all_validators)

I tried it with 3.0.0.a3 and Draft4Validator, Draft6Validator and Draft7Validators. No problems.

The sample I provided didn't really what show what we were doing. We are adding a new validator to check a number against a regex pattern.

def custom_number_pattern_validator(validator, value, instance, schema):
    if isinstance(instance, Number):
        if re.match(value, str(instance)) is None:
            yield ValidationError(f'{instance} does not pass number pattern format check.')

# extend the validator to include our custom validation...
VALIDATOR = validators.extend(validator=Draft7Validator,
                              validators={'customNumberPattern': custom_number_pattern_validator})

To us this was a clear win because we have conditions where a number should be a certain amount of max decimal places, a certain max 'size' to the right and left of the decimal, stuff like that. We can express that 'rule' with a regex, return an error if it doesn't match and skip coding that logic everywhere it's needed. I suppose we could make the type 'string' and use 'pattern' but for some reason that just seems wrong when we really do have a number data type. :)

I'm going to stay with the 3.0.0.a3 and the Draft 7 validator while we develop.
Thanks again for your help.
Tim

[timbouffard]

Sorry, didn’t mean to close 😊 From: Julian Berman <notifications@github.com> Sent: Thursday, January 10, 2019 4:59 PM To: Julian/jsonschema <jsonschema@noreply.github.com> Cc: Bouffard, Tim <bouffard@isc.upenn.edu>; State change <state_change@noreply.github.com> Subject: Re: [Julian/jsonschema] Error in early release 3.0.0.a3 but not in 2.6.0 (#509) Reopened #509<#509>. — You are receiving this because you modified the open/close state. Reply to this email directly, view it on GitHub<#509 (comment)>, or mute the thread<https://github.com/notifications/unsubscribe-auth/AG7TTPnC2KFMjYqg1kIXQab7zWPe6vIUks5vB8WYgaJpZM4Zk9Dc>.

[Julian]

No worries!