[json] publish schema of the VS Code-specific JSON Schema extensions

[pboushy]

Microsoft has extended JSON Schema 7.0 as part of VSCode. It would be great for Microsoft to publish a "VSCode JSON Schema" so that we can easily find all the available elements for our JSON Schemas.

Example extension that Microsoft did:
defaultSnippets as mentioned at the bottom of https://code.visualstudio.com/Docs/languages/json

[vscodebot]

(Experimental duplicate detection)
Thanks for submitting this issue. Please also check if it is already covered by an existing one, like:

• Adding/Updating json schema programmatically from third party plugin (#79363)
• Localizaton of jsonValidation schema (#78737)
• json.schemas setting for matching schema based on a JSON property in the file (#80712)
• [json] schema validation should support defining the problem severity (#29527)
• Print warning when contributing second search provider for same schema (#59360)

[pboushy]

It looks like someone mentioned in a comment doing this, but the actual feature (“suggest specific schema”) was rejected. #67761
I’m now requesting what @octref mentioned in that comment.

[aeschli]

These are really meant to be internal, for our settings editors.
Where would you want to use it?

[pboushy]

@aeschli I'm creating a JSON Schema to use with VS Code. (https://github.com/prbsparx/JsonSchemas/blob/master/k8s.networkpolicies.calico.json) I have the YAML extension from Redhat installed, and noticed that when I put in a string that doesn't match my pattern (e.g. IP Address regex) VS code says "string does not match pattern of " which is not friendly to me or my coworkers who will be using it.
I want to be able to say "string is not a valid CIDR Network Address"
I believe that VS Code has the ability to provide a custom error (patternErrorMessage) but can't confirm what the schema terms are that VS Code uses.

[vepanimas]

@aeschli, did I understand correctly that "defaultSnippets" is not even supported for the third-party extensions at the moment? Are there any workarounds to make it work, or do we need to wait for implementation in the VSCode itself?

[aeschli]

'defaultSnippets' and 'patternErrorMessage;' and others in JSON schemas can be defined by anyone, but is something that the VScode JSON language server invented. It only make sense to use within VSCode. Any extension that defined new configuration settings or contributes a JSON can use it, there are no limitations.
Here's the full list: https://github.com/microsoft/vscode-json-languageservice/blob/8020161a681184ce13b349731a11cdae76020c9a/src/jsonSchema.ts#L58

[vepanimas]

@aeschli ok, great. Thank you for the quick response!