message: Don't pretend you resolved a document by using an empty string anymore.
diff: @@ -523,10 +523,9 @@ export class StreamLoader implements UrlLoader {
  this.deferredFiles.delete(filePath);
  }
  - canLoad(_url: string): boolean {
  - // We want to return true for all files. Even external files, so that we
  - // can resolve them as empty strings for now.
  - return true;
  + // We can't load external dependencies.
  + canLoad(url: string): boolean {
  + return !isDependencyExternal(url);
  }
  load(url: string): Promise<string> {
  @@ -536,7 +535,7 @@ export class StreamLoader implements UrlLoader {
  // Resolve external files as empty strings. We filter these out later
  // in the analysis process to make sure they aren't included in the build.
  if (isDependencyExternal(url)) {
  - return Promise.resolve('');
  + return Promise.resolve(undefined);
  }
  const urlPath = decodeURIComponent(urlObject.pathname);
  