Schema validation error on hyperschema link with $ref

[ricobl]

I've got the following error trying to validate a schema with a reference on a link:

ValidationError: u'#' is not of type u'object'

The base schema:

{
    "$ref": "http://json-schema.org/draft-03/hyper-schema#"
}

Here is a stripped version of the schema I'm trying to validate:

{
    "$schema": "http://json-schema.org/draft-03/hyper-schema#",
    "links": [
        {
            "href": "{id}",
            "method": "POST",
            "rel": "create",
            "schema": {
                "$ref": "#"
            }
        }
    ]
}

I've forked the project and added a test exploring this issue:
ricobl@565084f#diff-d41d8cd98f00b204e9800998ecf8427e

I didn't get any error using the online validators:
https://json-schema-validator.herokuapp.com/
http://jsonschemalint.com/

Looks like the validator isn't expanding the $ref, trying to validate the schema URI as an object.

Any clues?

[Julian]

Works for me:

⊙  python -c 'from jsonschema import validate, __version__; print __version__; validate({ "$ref": "http://json-schema.org/draft-03/hyper-schema#" }, { "$schema": "http://json-schema.org/draft-03/hyper-schema#", "links": [ { "href": "{id}", "method": "POST", "rel": "create", "schema": { "$ref": "#" } } ] })'
2.3.0

Can you show an example that reproduces and what version you're on?

[ricobl]

I'm on 2.3.0 too!

By using validate it uses the Draft4Validator if it doesn't find a registered meta-schema, but I'm trying to use a draft 3 hyper schema.

So I think we should use the draft 3 implementation to validate a draft 3 hyper schema. If we force the Draft3Validator it will raise the error I've mentioned:

python -c 'from jsonschema import Draft3Validator, __version__; print __version__; Draft3Validator({ "$ref": "http://json-schema.org/draft-03/hyper-schema#" }).validate({ "$schema": "http://json-schema.org/draft-03/hyper-schema#", "properties": { "name": {"required": True}}, "links": [ { "href": "{id}", "method": "POST", "rel": "create", "schema": { "$ref": "#" } } ] })'

If we use the Draft4Validator it won't raise the error.

python -c 'from jsonschema import Draft4Validator, __version__; print __version__; Draft4Validator({ "$ref": "http://json-schema.org/draft-03/hyper-schema#" }).validate({ "$schema": "http://json-schema.org/draft-03/hyper-schema#", "properties": { "name": {"required": True}}, "links": [ { "href": "{id}", "method": "POST", "rel": "create", "schema": { "$ref": "#" } } ] })'

Makes any sense? Am I missing something?

[Julian]

Ah I see, sorry, I was careless.

Yes now I can reproduce, but I'd probably need to spend a bit of time diagnosing to figure out what's up, nothing looks immediately obvious.

If you've figured anything out yourself, would love to hear it.

[ricobl]

No problem!

I tried to extend the validators to create hyperschema validators but had no success, I just don't remember why right now...

I couldn't figure out anything else so far.

[Julian]

So, after a long while I took a quick look at this just now. Ultimately what this ends up resolving to in a minimal-ish reproducing case is:

schema = {'additionalProperties': {'$ref': 'http://json-schema.org/draft-03/hyper-schema#'}}
instance = {'$ref': '#'}

which I think is correctly failing. I'm not sure why the apps you linked are green, they possibly are not even resolving the refs in the first place.

I see roughly what you're trying to do, which makes me think something is wrong with the draft 3 meta schema, but given that we're on the way to draft 5 I think the ship might have sailed there.

I'm going to close this out but feel free to follow up if you're still alive and care, sorry this took so long.

[ricobl]

Sounds fair @Julian! Thanks for your time.