#
#
# patch "selectors.cc"
#  from [a8470d1bec571facb22f9244a0e2e37cd83a7b59]
#    to [ec7d5023812047d31781d25a8a549e28605ddb26]
#
============================================================
--- selectors.cc	a8470d1bec571facb22f9244a0e2e37cd83a7b59
+++ selectors.cc	ec7d5023812047d31781d25a8a549e28605ddb26
@@ -90,6 +90,9 @@ public:
 public:
   key_selector(string const & arg, lua_hooks & lua, project_t & project)
   {
+    E(!arg.empty(), origin::user,
+      F("the key selector k: must not be empty"));
+
     project.get_key_identity(lua,
                              external_key_name(arg, origin::user),
                              identity);