protected List<VirtualFile> prepareWritable(final Collection<VirtualFile> files) {
        final List<VirtualFile> writable = new ArrayList<>();
        for (VirtualFile vf : files) {
          if (myVcs.equals(myPlVcsManager.getVcsFor(vf))) {
            writable.add(vf);
          }
        }
        final ReadonlyStatusHandler.OperationStatus operationStatus =
          ReadonlyStatusHandler.getInstance(myVcs.getProject()).ensureFilesWritable(writable);
        writable.removeAll(Arrays.asList(operationStatus.getReadonlyFiles()));

        return writable;
      }
protected List<VirtualFile> prepareWritable(final Collection<VirtualFile> files)