diff --git a/index-debuginfo.cc b/index-debuginfo.cc
index eedd8fa..8dd7dba 100644
--- a/index-debuginfo.cc
+++ b/index-debuginfo.cc
@@ -36,7 +36,7 @@ void mainWrapped(int argc, char * * argv)
         json["archive"] = url;
         json["member"] = filename;
 
-        std::string key = "debuginfo/" + buildId;
+        std::string key = "debuginfo/" + build_id;
 
         // FIXME: or should we overwrite? The previous link may point
         // to a GC'ed file, so overwriting might be useful...