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JSON Schema: Using $ref to an internal $id is flagged as an error

See original GitHub issue

Describe the bug When linting a self-contained JSON schema, using a $ref to refer to an internal sub-schema by $id is reported as an error.

To Reproduce

Grab the “Using $id with $ref” example from Understanding JSON Schema
Run spectral lint -F hint -v schema.json

Expected behavior Should be a valid schema

Actual behavior

Found 52 rules (36 enabled)
Linting <file>
JSON Schema detected
JSON Schema (loose) detected
JSON Schema Draft 7 detected

<file>
 28:15  error  invalid-ref  ENOENT: no such file or directory, open ''

✖ 1 problem (1 error, 0 warnings, 0 infos, 0 hints)

Environment:

Library version: 4.2.0 (I can’t test with latest due to #1097)
OS: Mac OS Mokave
Node: v13.13.0

Issue Analytics

State:
Created 3 years ago
Comments:6 (5 by maintainers)

Top GitHub Comments

1reaction

P0lipcommented, May 3, 2020

Would you mind explaining briefly why it’s not a valid pointer?

Spectral does not support resolving based on $id - it’s the property that’s simply unrecognized by us. If you want to reference a place in the document, you need to use a valid JSON Pointer, such as #/definitions/address, as explained in the extending section of the article you linked.

Any ideas why it’s documented in this popular online guide and it works in 2 schema parsers I’m using when it’s not valid? Just trying to understand the landscape.

Spectral is technically not a JSON Schema validator, therefore we don’t support all of the resolving features that JSON Schema provides. I’m not sure whether I was helpful or not, but please do feel free to ask further questions if something is uncertain.

0reactions

philsturgeoncommented, May 4, 2020

Context: Seeing as Spectral is a tool which aims to work with OpenAPI and JSON Schema, but those two formats are only mostly compatible, there are a few quirks like this which pop up.

OpenAPI does not allow $id, so resolving via $id is commonly not supported in tooling which works with OpenAPI, even though a lot of that tooling says it supports JSON Schema too. I know. This is a mess.

Seeing as OpenAPI v3.1 will be proper JSON Schema, $id will be allowed, and all JSON Ref tooling is now scrambling to add proper support. We’re ditching our own json-ref-resolver to help json-schema-ref-parser get better, and they’re adding $id support, so soon this problem will have gone away.

tldr: for now please try and avoid $ref’ing to $id and point to its location in the file using a more standard JSON Pointer instead.

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