Customizing One Resolver Removes Other Default Resolvers

[dillonredding]

Describe the bug
In an attempt to work around #1314, I found that when overriding only the file $ref resolver, the default http and https $ref resolvers are not used and are replaced with the provided file $ref resolver.

To Reproduce

C:/api/openapi.yaml:

openapi: 3.0.3
info:
  title: Test API
  version: 1.0.0
paths:
  /test:
    get:
      responses:
        '200':
          $ref: components.yaml#/Ok
        '400':
          $ref: https://gist.githubusercontent.com/dillonredding/4b3792af17a7335bca325b64cbf74e74/raw/4e450ed7b12c87f99245ee0bf20db08497130508/openapi-components.yaml#/BadRequest

C:/api/components.yaml:

Ok:
  description: Success

C:/dev/script.ts:

import fs from 'fs';
import YAML from 'js-yaml';
import path from 'path';
import { Resolver } from '@stoplight/json-ref-resolver';
import { isOpenApiv3, Spectral } from '@stoplight/spectral';
import { DiagnosticSeverity } from '@stoplight/types';

const openApi = fs.readFileSync('C:/api/openapi.yaml', 'utf-8');

const resolver = new Resolver({
    resolvers: {
        file: {
            resolve: ref =>
                fs.promises.readFile(path.join('C:/api', ref.path()), 'utf-8')
        }
    }
});

const spectral = new Spectral({ resolver });
spectral.registerFormat('oas3', isOpenApiv3);
spectral.run(YAML.safeLoad(openApi) as string)
    .then(results => {
        results.filter(result => result.severity === DiagnosticSeverity.Error)
            .forEach(result => console.log(result.message))
    });

$ ts-node C:\dev\script.ts
ENOENT: no such file or directory, open 'C:\api\dillonredding\4b3792af17a7335bca325b64cbf74e74\raw\4e450ed7b12c87f99245ee0bf20db08497130508\openapi-components.yaml'

Expected behavior
According to the documentation:

If you'd like [to ...] adjust the resolution, you are absolutely fine to do it. In order to achieve that, you need to create a custom json-ref-resolver instance. [Emphasis mine]

I interpret this as being able to customize specific resolvers. Customizing the file $ref resolver shouldn't require reimplementing the others.

Environment:

• TypeScript: v3.9.6
• Spectral: v5.5.0
• Node: v12.15.0
• Windows: 10 Enterprise

[nulltoken]

@dillonredding Sadly, it's possible the documentation is indeed misleading on that topic. Thanks for pointing that out.

There would be two ways addressing that:

• Either enhance the documentation to make it clearer that "adjusting" requires re-implementing the standard schemes
• Tweak the code in https://github.com/stoplightio/spectral/blob/c021b045e9c8c76bb3ee4dc624edc7779c05b369/src/resolvers/http-and-file.ts so that's easier to potentially inject overriden resolvers per scheme

[philsturgeon]

Tweak the code in https://github.com/stoplightio/spectral/blob/c021b045e9c8c76bb3ee4dc624edc7779c05b369/src/resolvers/http-and-file.ts so that's easier to potentially inject overriden resolvers per scheme

I think this will be the way to go, as we're already planning to make resolvers more easily injectable for #1054.