diff --git a/proto_library.gni b/proto_library.gni
index 1ede629..3017002 100644
--- a/proto_library.gni
+++ b/proto_library.gni
@@ -345,8 +345,13 @@
                              "testonly",
                              "visibility",
                            ])
-
-    sources = get_target_outputs(":$action_name")
+    sources = []
+    foreach(source, get_target_outputs(":$action_name")) {
+      extension = get_path_info(source, "extension")
+      if (extension == "h" || extension == "cc" ) {
+        sources += [ source ]
+      }
+    }
 
     if (defined(invoker.extra_configs)) {
       configs += invoker.extra_configs