$ref in $ref causes path hash to be repeated.

[supertong]

Hey, first of all, thanks for the great library. I think I spot an edge case bug when using it.
Here is the JSON file that I have simplified a lot to demo the problem.

{
  "$ref": "#/definitions/doc_node",
  "definitions": {
    "top_level_node": {
      "type": "object"
    },
    "doc_node": {
      "type": "object",
      "properties": {
        "content": { "$ref": "#/definitions/top_level_node" }
      }
    }
  }
}

And when I tried to bundle it

const parser = new RefParser();
parser
  .bundle('./bug-schema.json')
  .then((s) => {
    console.log(JSON.stringify(s, null, 2))
  });

it generates output

{
  "$ref": "#/definitions/doc_node",
  "definitions": {
    "top_level_node": {
      "type": "object"
    },
    "doc_node": {
      "type": "object",
      "properties": {
        "content": {
          "$ref": "#/definitions/top_level_node/definitions/top_level_node"
        }
      }
    }
  }
}

As you can see, the 'definitions/top_level_node' is duplicated in doc_node. And I also did some debugging myself. It turns out that problem happens around here

Pointer.prototype.resolve = function(obj, options) {
  var tokens = Pointer.parse(this.path);

  // Crawl the object, one token at a time
  this.value = obj;
  for (var i = 0; i < tokens.length; i++) {
    if (resolveIf$Ref(this, options)) {
      // The $ref path has changed, so append the remaining tokens to the path
      this.path = Pointer.join(this.path, tokens.slice(i));  <== This line
    }

    var token = tokens[i];
    if (this.value[token] === undefined) {
      throw ono.syntax('Error resolving $ref pointer "%s". \nToken "%s" does not exist.', this.path, token);
    }
    else {
      this.value = this.value[token];
    }
  }

  // Resolve the final value
  resolveIf$Ref(this, options);
  return this;
};

I was trying to figure out what is the code doing here. My immature assumption is that resolveIf$Ref is checking if current object has a $ref and if it has one, it will be resolved. However, one thing I don't understand is the reason behind this path updating. May be it has something todo with line here ? Can we not update the path?

I understand you are busy and hope you could shed some light on this. I am happy to create a PR if you could understand the purpose of the path updating logic.

Cheers

[supertong]

Ahh, I think I kind of understand how the path changes better now. And, according to the comment, I think we shall return false here?

function resolveIf$Ref(pointer, options) {
  // Is the value a JSON reference? (and allowed?)

  if ($Ref.isAllowed$Ref(pointer.value, options)) {
    var $refPath = url.resolve(pointer.path, pointer.value.$ref);

    if ($refPath === pointer.path) {
      // The value is a reference to itself, so there's nothing to do.
      pointer.circular = true;
    }
    else {
      var resolved = pointer.$ref.$refs._resolve($refPath, options);

      if ($Ref.isExtended$Ref(pointer.value)) {
        // This JSON reference "extends" the resolved value, rather than simply pointing to it.
        // So the resolved path does NOT change.  Just the value does.
        pointer.value = $Ref.dereference(pointer.value, resolved.value);
        return false;  <====== HERE
      }
      else {
        // Resolve the reference
        pointer.$ref = resolved.$ref;
        pointer.path = resolved.path;
        pointer.value = resolved.value;
      }

      return true;
    }
  }
}

[supertong]

Hey, I raised a PR for it. Let me know if it's more complicated than I thought. :)

[JamesMessinger]

Thank you very much for the PR! Great catch!