diff --git a/tool/redmine-backporter.rb b/tool/redmine-backporter.rb
index a7bce96fe2..2ce181b63c 100755
--- a/tool/redmine-backporter.rb
+++ b/tool/redmine-backporter.rb
@@ -437,7 +437,7 @@ eom
     end
 
     if system("svn info #{RUBY_REPO_PATH&.shellescape}", %i(out err) => IO::NULL) # SVN
-      if log = find_svn_log("##@issue]") && /revision="(?<rev>\d+)/ =~ log
+      if (log = find_svn_log("##@issue]")) && (/revision="(?<rev>\d+)/ =~ log)
         rev = "r#{rev}"
       end
     else # Git