Review

10

com/google/javascript/jscomp/JSModuleGraph.java

coalesceDuplicateFiles()

class JSModuleGraph {
  /**
   * Replaces any files that are found multiple times with a single instance in
   * the closest parent module that is common to all modules where it appears.
   *
   * JSCompiler normally errors if you attempt to compile modules containing the
   * same file.  This method can be used to remove duplicates before compiling
   * to avoid such an error.
   */
  public void coalesceDuplicateFiles() {
    Multimap<String, JSModule> fileRefs = LinkedHashMultimap.create();
    for (JSModule module : modules) {
      for (CompilerInput jsFile : module.getInputs()) {
        fileRefs.put(jsFile.getName(), module);
      }
    }

    for (String path : fileRefs.keySet()) {
      Collection<JSModule> refModules = fileRefs.get(path);
      if (refModules.size() > 1) {
        JSModule depModule = getDeepestCommonDependencyInclusive(refModules);
        CompilerInput file = refModules.iterator().next().getByName(path);
        for (JSModule module : refModules) {
          if (module != depModule) {
            module.removeByName(path);
          }
        }
        if (!refModules.contains(depModule)) {
          depModule.add(file);
        }
      }
    }
  }

}