Reference resolution issue in v7

[solymosi]

I'm using version 7.0.3.

Consider the following piece of code:

const Ajv = require("ajv").default;

const instance = new Ajv({
  loadSchema: uri => {
    return Promise.resolve({
      $id: "http://two/",
      type: "object",
      properties: {
        bar: {
          $ref: "#/definitions/bar",
        },
      },
      definitions: {
        bar: {
          type: "string",
        },
      },
    });
  },
});

instance.compileAsync(
  {
    $id: "http://one/",
    type: "object",
    properties: {
      foo: {
        $ref: "#/definitions/foo",
      },
    },
    definitions: {
      foo: {
        $ref: "http://two/",
      },
    },
  },
  false
);

For whatever reason when processing the lazy loaded schema http://two/ Ajv thinks that the base URL is still http://one/ and tries to resolve the bar property reference accordingly, resulting in this error:

Error: AnySchema http://one/ is loaded but http://one/#/definitions/bar cannot be resolved
    at Ajv.checkLoaded (D:\dev\cis-dm-core\node_modules\ajv\lib\core.ts:377:15)
    at Ajv._compileAsync (D:\dev\cis-dm-core\node_modules\ajv\lib\core.ts:369:21)
    at Ajv._compileAsync (D:\dev\cis-dm-core\node_modules\ajv\lib\core.ts:371:30)

This problem is new in version 7, it first popped up after upgrading from version 6.

I've spent several hours debugging this issue and it seems like that changing this line:
https://github.com/ajv-validator/ajv/blob/v7.0.3/lib/compile/index.ts#L265

if (id === normalizeId(ref)) return new SchemaEnv({schema: schOrRef.schema, root, baseId})

to

if (id === normalizeId(ref)) return new SchemaEnv({schema: schOrRef.schema, root, schOrRef.baseId})

solves the issue in this particular case. I don't have enough knowledge of the codebase to be able to tell if this is the proper fix though, i.e. whether it could break something else.

If #/definitions/foo is inlined:

instance.compileAsync(
  {
    $id: "http://one/",
    type: "object",
    properties: {
      foo: {
        $ref: "http://two/",
      },
    },
  },
  false
);

then everything works as expected.

[epoberezkin]

is it specific to async loading, or it happened for schema added with addSchema as well?

[solymosi]

@epoberezkin It is indeed also broken if I use addSchema, and even when using compile instead of compileAsync. Thus, it's purely a reference resolution issue, it likely has nothing to do with the way the schemas are loaded.

const Ajv = require("ajv").default;

const instance = new Ajv({
  loadSchema: () => undefined,
});

instance.addSchema({
  $id: "http://two/",
  title: "Properties",
  type: "object",
  properties: {
    bar: {
      $ref: "#/definitions/bar",
    },
  },
  definitions: {
    bar: {
      type: "string",
    },
  },
});

instance.compile(
  {
    $id: "http://one/",
    type: "object",
    properties: {
      foo: {
        $ref: "#/definitions/foo",
      },
    },
    definitions: {
      foo: {
        $ref: "http://two/",
      },
    },
  },
  false
);

Error: can't resolve reference #/definitions/bar from id http://one/#

[epoberezkin]

@solymosi thank you

I can reproduce: https://runkit.com/esp/601700c43e06c0001a957eff

It indeed happens in v7 and not in v6 - good catch.