bug: os.date throws error when result is the empty string

bugs

@@ -1142,6 +1142,15 @@ patch = [[
 }
 
 
+Bug{
+what = [[os.date throws an error when result is the empty string]],
+report = [[  ]],
+since = [[4.0]],
+example = [[print(os.date(""))]],
+patch = [[  ]],
+}
+
+
 Bug{
 what = [[  ]],
 report = [[  ]],