message: Bug fix to merger.
diff: @@ -61,8 +61,8 @@ export class MultiAPIMerger extends MultiProcessor<any, oai.Model> {
  }
  public process(target: ProxyObject<oai.Model>, nodes: Iterable<Node>) {
  - for (const { key, value, pointer, children } of nodes) {
  + for (const { key, value, pointer, children } of nodes) {
  switch (key) {
  case 'paths':
  if (!this.isSecondaryFile) {
  @@ -156,6 +156,7 @@ export class MultiAPIMerger extends MultiProcessor<any, oai.Model> {
  // change local refs to full ref
  value.$ref = `${this.key}${ref}`;
  }
  +
  // now, recurse into this object
  this.expandRefs(value);
  }
  @@ -169,7 +170,7 @@ export class MultiAPIMerger extends MultiProcessor<any, oai.Model> {
  protected updateRefs(node: any) {
  for (const { key, value } of visit(node)) {
  - if (typeof value === 'object') {
  + if (value && typeof value === 'object') {
  const ref = value.$ref;
  if (ref) {
  // see if this object has a $ref
  