YAML Language Server checks against JSON Schema Draft 7 instead of the defined one

[ngregory-rbi]

Describe the bug

Expected Behavior

The YAML Language Server respects the $schema property and checks against the meta-schema defined by it.

Current Behavior

The YAML Language Server ignores the $schema property and instead checks against the JSON Schema Draft 7 meta-schema.

Steps to Reproduce

1. Open VSCode
2. Create a new file called openapi.yml
3. Switch the schema to version 3.0 (based on the added feature for Support versions from schemastore #639)
4. Type anything
5. Observe the error:

Schema 'schema.json' is not valid:
/definitions/Schema/properties/multipleOf/exclusiveMinimum : must be number

The Open API v3.0 schema uses the $schema property like so:

  "$schema": "http://json-schema.org/draft-04/schema#",

In Draft 4, exclusiveMinimum MUST be a boolean.

However, in the latest draft (currently 2020-12), exclusiveMinimum MUST be a number. It appears this is the meta-schema the language server is checking against, despite the schema specifically specifying Draft 4.

EDIT: It appears to be checking against Draft 7, which does also say exclusiveMinimum MUST be a number.

EDIT 2: Ok so Draft 4 is REALLY old and is no longer in ajv (the tool used to validate the schema). Not sure if this needs to be actioned, or if one would just need to wait for additional tooling (like Swagger) to finally support v3.1.

Environment

• Windows
• Mac
• Linux
• other (please specify)

[okybr]

check this out: https://github.com/okybr/yaml-language-server/blob/0c344c441be72b7fffc7b2d98a81ef9113aced76/README.md

related issues:

• OpenAPI 3.0.0 specification is treated as invalid #752
• Is this line correct? YAML LSP says the scheme is not valid because of this OAI/OpenAPI-Specification#2969

[KillDozerX2]

Is anybody picking this up?

[okybr]

you could just merge this commit in order to fix it: okybr@455d452

edit: we need a better solution. a solution that makes it possible to choose the draft version.

[KillDozerX2]

Okay, I might have something up my sleeve for this.

[amimas]

Any update available on this? I'm looking into creating some schema and it'd be great if I could use the 2020-12 schema.

[okybr]

@gorkem, this is not an enhancement, it's a bug!

@KillDozerX2, have you found time to work on this?

[KillDozerX2]

@gorkem, this is not an enhancement, it's a bug!

@KillDozerX2, have you found time to work on this?

Apologies, I haven't looked into this yet.

[Davidonium]

I encountered this and answered in a similar issue: #752 (comment)

After encountering this same issue and digging through why this happens, I believe that the issue is that ajv, the library used for json schema validation, does not support the draft-04 version because there's no security support for it.
See:

• The line having ajv v8 as a dep https://github.com/redhat-developer/yaml-language-server/blob/main/package.json#L33
• The docs that say there's no support in ajv and prompt the user to use v6 https://ajv.js.org/guide/schema-language.html#draft-04

[Davidonium]

I created a PR trying to assess this. #1006
I got inspiration from @okybr's proposal.