diff --git a/mysql-test/t/group_by.test b/mysql-test/t/group_by.test
index 4631fad3352..043adb97c64 100644
--- a/mysql-test/t/group_by.test
+++ b/mysql-test/t/group_by.test
@@ -612,6 +612,16 @@ SELECT n+1 AS n FROM t1 GROUP BY n;
 --enable_ps_protocol
 DROP TABLE t1;
 
+#
+# BUG#12695: Item_func_isnull::update_used_tables
+# did not update const_item_cache
+#
+create table t1(f1 varchar(5) key);
+insert into t1 values (1),(2);
+select sql_buffer_result max(f1) is null from t1;
+select sql_buffer_result max(f1)+1 from t1;
+drop table t1;
+
 # End of 4.1 tests
 
 #
diff --git a/sql/handler.cc b/sql/handler.cc
index cf1fbfec465..3acca812a13 100644
--- a/sql/handler.cc
+++ b/sql/handler.cc
@@ -570,12 +570,20 @@ int ha_prepare(THD *thd)
     {
       int err;
       statistic_increment(thd->status_var.ha_prepare_count,&LOCK_status);
-      if ((err= (*(*ht)->prepare)(thd, all)))
+      if ((*ht)->prepare)
       {
-        my_error(ER_ERROR_DURING_COMMIT, MYF(0), err);
-        ha_rollback_trans(thd, all);
-        error=1;
-        break;
+        if ((err= (*(*ht)->prepare)(thd, all)))
+        {
+          my_error(ER_ERROR_DURING_COMMIT, MYF(0), err);
+          ha_rollback_trans(thd, all);
+          error=1;
+          break;
+        }
+      }
+      else
+      {
+        push_warning_printf(thd, MYSQL_ERROR::WARN_LEVEL_WARN,
+                            ER_ILLEGAL_HA, ER(ER_ILLEGAL_HA), (*ht)->name);
       }
     }
   }