bug #27531:

 fixed coverage of out-of-mem errors

sql/item_subselect.cc

@@ -1787,7 +1787,7 @@ int subselect_single_select_engine::exec()
       select_lex->uncacheable|= UNCACHEABLE_EXPLAIN;
       select_lex->master_unit()->uncacheable|= UNCACHEABLE_EXPLAIN;
       if (join->init_save_join_tab())
-        DBUG_RETURN(1);
+        DBUG_RETURN(1);                        /* purecov: inspected */
     }
     if (item->engine_changed)
     {

sql/sql_select.cc

@@ -1432,7 +1432,7 @@ JOIN::optimize()
     */
     if (select_lex->uncacheable && !is_top_level_join() &&
         init_save_join_tab())
-      DBUG_RETURN(-1);
+      DBUG_RETURN(-1);                         /* purecov: inspected */
   }
 
   error= 0;
@@ -1509,7 +1509,7 @@ bool
 JOIN::init_save_join_tab()
 {
   if (!(tmp_join= (JOIN*)thd->alloc(sizeof(JOIN))))
-    return 1;
+    return 1;                                  /* purecov: inspected */
   error= 0;				       // Ensure that tmp_join.error= 0
   restore_tmp();
   return 0;