$ref resolution process change in v7 (bug in v6)

Apologies for the fairly long JSON schema. It is a stripped down version of a quite large schema which is being bundled using json-schema-ref-parser. The problem occurs with the $ref values. The ajv-cli version 3.3.0 compiles the schema and claims it is valid. Newer versions of AJV can’t compile as it cannot resolve the reference.

The problem seems to be that the $ref for property ContainedWithin is pointing to ShipperBookingLineParent which in turn points to ShipperBookingLine.

• I know it’s a bit convoluted, but is AJV supposed to be able to resolve that kind of reference (apparently in older version it was ok) or is it not supported anymore?

It is possible to update the $ref by removing parts of it (ShipperBookingLineParent/allOf/5/properties/) however the non-stripped down schema has many $ref which are created by json-schema-ref-parser so I am not able to post process them in a meaningful manner as some would require removal and others replacement of paths. Perhaps also worth mentioning that the tool Stoplight Studio has no problem resolving the reference.

What version of Ajv are you using? Does the issue happen if you use the latest version? ajv-cli 5.0.0 ajv 8.0.5 (Have a Javascript running with this version, same result)

Ajv options object Not used - running with defaults

JSON Schema

{
  "$schema": "http://json-schema.org/draft-07/schema#",
  "$id": "/models/01-MaerskInformationModel-Bundled/Booking/ShipperBooking/ShipperBooking-bundled.v1-stripped.json",
  "type": "object",
  "properties": {
    "ShipperBookingLines": {
      "type": "array",
      "items": {
        "type": "object",
        "properties": {
          "DangerousCargoInformation": {
            "type": "object",
            "properties": {
              "HazardousClassification": {
                "type": "object",
                "properties": {
                  "RequiredDangerousCommodityPackageType": {
                    "type": "object",
                    "properties": {
                      "AwesomeProperty": {
                        "type": "string"
                      },
                      "ContainedWithin": {
                        "$ref": "#/properties/ShipperBookingLines/items/properties/ShipperBookingLineParent/properties/DangerousCargoInformation/properties/HazardousClassification/properties/RequiredDangerousCommodityPackageType"
                      }
                    }
                  }
                }
              }
            }
          },
          "ShipperBookingLineParent": {
            "$ref": "#/properties/ShipperBookingLines/items"
          }
        }
      }
    }
  }
}

Sample data

Not applicable, schema compilation fails

Your code

npx ajv-cli compile -s ShipperBooking-bundled.v1-stripped.json

Validation result, data AFTER validation, error messages ajv-cli:

schema ShipperBooking-bundled.v1-stripped.json is invalid
error: can't resolve reference #/properties/ShipperBookingLines/items/properties/ShipperBookingLineParent/properties/DangerousCargoInformation/properties/HazardousClassification/properties/RequiredDangerousCommodityPackageType from id /models/01-MaerskInformationModel-Bundled/Booking/ShipperBooking/ShipperBooking-bundled.v1-stripped.json

ajv:

MissingRefError: can't resolve reference #/properties/ShipperBookingLines/items/properties/ShipperBookingLineParent/properties/DangerousCargoInformation/properties/HazardousClassification/properties/RequiredDangerousCommodityPackageType from id /models/01-MaerskInformationModel-Bundled/Booking/ShipperBooking/ShipperBooking-bundled.v1-stripped.json
    at Object.code (C:\dev\workspace2\JSON-schema-test\node_modules\ajv\dist\vocabularies\core\ref.js:21:19)
    at keywordCode (C:\dev\workspace2\JSON-schema-test\node_modules\ajv\dist\compile\validate\index.js:451:13)
    at C:\dev\workspace2\JSON-schema-test\node_modules\ajv\dist\compile\validate\index.js:185:25
    at CodeGen.code (C:\dev\workspace2\JSON-schema-test\node_modules\ajv\dist\compile\codegen\index.js:439:13)
    at CodeGen.block (C:\dev\workspace2\JSON-schema-test\node_modules\ajv\dist\compile\codegen\index.js:568:18)
    at schemaKeywords (C:\dev\workspace2\JSON-schema-test\node_modules\ajv\dist\compile\validate\index.js:185:13)
    at typeAndKeywords (C:\dev\workspace2\JSON-schema-test\node_modules\ajv\dist\compile\validate\index.js:129:5)
    at subSchemaObjCode (C:\dev\workspace2\JSON-schema-test\node_modules\ajv\dist\compile\validate\index.js:116:5)
    at subschemaCode (C:\dev\workspace2\JSON-schema-test\node_modules\ajv\dist\compile\validate\index.js:92:13)
    at KeywordCxt.subschema (C:\dev\workspace2\JSON-schema-test\node_modules\ajv\dist\compile\validate\index.js:425:9) {
  missingRef: '/models/01-MaerskInformationModel-Bundled/Booking/ShipperBooking/ShipperBooking-bundled.v1-stripped.json#/properties/ShipperBookingLines/items/properties/ShipperBookingLineParent/properties/DangerousCargoInformation/properties/HazardousClassification/properties/RequiredDangerousCommodityPackageType',
  missingSchema: '/models/01-MaerskInformationModel-Bundled/Booking/ShipperBooking/ShipperBooking-bundled.v1-stripped.json'
}

What results did you expect? That the schema compiles as it does with ajv-cli 3.3.0

Are you going to resolve the issue? I am not familiar with the AJV source code, so I can’t.

[Relequestual]

The part of the specification where this is defined is found at https://datatracker.ietf.org/doc/html/draft-bhutton-json-schema-00#section-9.3

I’ve written 99% of a blog post which explains it a little, and it’s pending publication.

Part of the problem with how json-schema-ref-parser works, and what changed in 2019-09 made things even worse (for the library). You can read about key comments here: https://github.com/APIDevTools/json-schema-ref-parser/issues/145

If you’re allergic to reading RFC spec documents, you could join the JSON Schema slack and watch out for updates on the announcements channel for the blog posting on bundling.

There wasn’t a defined bundling process before, and it’s somewhat easier to define with the changes we made in 2019-09 (outlined in that link above).

[philsturgeon]

I see, looks like the trouble is coming from:

                    "ContainedWithin": {
                        "$ref": "#/properties/ShipperBookingLines/items/properties/ShipperBookingLineParent/properties/Dangerous...

When ShipperBookingLineParent only has a $ref and no properties.

      "ShipperBookingLineParent": {
            "$ref": "#/properties/ShipperBookingLines/items"
      }

This is likely a problem with json-schema-ref-parser then. The Stoplight crew help maintain that package so we can try to take a look, but if anyone else has time feel free to take a look.