diff --git a/rules/common.smk b/rules/common.smk
index 1654180f..5aa7ae53 100644
--- a/rules/common.smk
+++ b/rules/common.smk
@@ -43,7 +43,7 @@ def memory(w):
 def input_custom_extra_functionality(w):
     path = config["solving"]["options"].get("custom_extra_functionality", False)
     if path:
-        return workflow.source_path(path)
+        return os.path.join(os.path.dirname(workflow.snakefile), path)
     return []