Extract JSON compatibility checking code into a separate module

[blacktooth]

One of our use-cases require the JSON compatibility checking feature of apicurio-registry. We want to know if it's possible to extract the JSON compatibility checker and related classes into a separately buildable module.

We cannot depend on the whole apicurio-registry repository as it would bring-in lot of dependencies like rest client, Protobuf, Avro, etc which we don't need.

Can we contribute this change?

[EricWittmann]

I don't think this would be difficult. In fact, we have our own goal of relocating the JSON compatibility checking from apicurio-registry repository into the apicurio-data-models repository. But that will require a rewrite of the functionality and a new JSON Schema data model in apicurio-data-models, so that won't happen too soon. Before that happens, I don't think it would be a big problem isolating the current functionality into a separate module for re-use.

@jsenko what do you think?

[blacktooth]

Since there is no standard for JSON compatibility checking (AKAIK), are you willing to publish the work done in this repository as specification for JSON schema evolution? We can think of creating a separate repository something like apicurio/json-schema-compatibility-checker.

I am open to contribute this.

This is still an open item on json schema org repo, json-schema-org/json-schema-vocabularies#5

[jsenko]

hi, I agree that moving it into a separate module should be OK for the short term. For the long term, we would like to relocate it into apicurio-data-models, as Eric mentioned.

[blacktooth]

Thanks for confirming! I created a PR to refactor the code to modularize this.

[EricWittmann]

Fixed in #1302