diff --git a/git/hooks/prepare-forward-merge b/git/hooks/prepare-forward-merge
index 76b308e3cbc..7cbdf21e9e0 100755
--- a/git/hooks/prepare-forward-merge
+++ b/git/hooks/prepare-forward-merge
@@ -27,7 +27,7 @@ end
 def rewrite_message(message_file, fixed)
   current_branch = `git rev-parse --abbrev-ref HEAD`.strip
   if current_branch == "main"
-    current_branch = $main_branch
+    return nil
   end
   rewritten_message = ""
   message = File.read(message_file)
@@ -68,4 +68,6 @@ end
 $log.debug "Searching for for forward merge"
 fixed = get_fixed_issues()
 rewritten_message = rewrite_message(message_file, fixed)
-File.write(message_file, rewritten_message)
+unless rewritten_message.nil?
+  File.write(message_file, rewritten_message)
+end