diff --git a/lib/rdoc/rdoc.rb b/lib/rdoc/rdoc.rb
index 2da6d9b575..516731c874 100644
--- a/lib/rdoc/rdoc.rb
+++ b/lib/rdoc/rdoc.rb
@@ -125,12 +125,14 @@ def gather_files files
 
     file_list = remove_unparseable(file_list)
 
+    result = []
     if file_list.count {|name, mtime|
+         result << name if mtime || @options.force_update
          file_list[name] = @last_modified[name] unless mtime
          mtime
        } > 0
       @last_modified.replace file_list
-      file_list.keys.sort
+      result.sort
     else
       []
     end
diff --git a/test/rdoc/test_rdoc_rdoc.rb b/test/rdoc/test_rdoc_rdoc.rb
index 5168932430..ae4f8904c1 100644
--- a/test/rdoc/test_rdoc_rdoc.rb
+++ b/test/rdoc/test_rdoc_rdoc.rb
@@ -80,6 +80,17 @@ def test_gather_files
     assert_equal [a, b], @rdoc.gather_files([b, a, b])
   end
 
+  def test_gather_files_with_no_force_update
+    a = File.expand_path __FILE__
+    b = File.expand_path '../test_rdoc_text.rb', __FILE__
+
+    assert_equal [a, b], @rdoc.gather_files([a, b])
+
+    @rdoc.last_modified[a] -= 10
+    @rdoc.options.force_update = false
+    assert_equal [a], @rdoc.gather_files([a, b])
+  end
+
   def test_handle_pipe
     $stdin = StringIO.new "hello"