MDEV-492: fixed incorrect error check.

mysql-test/r/errors.result

@@ -69,3 +69,11 @@ ERROR 42S22: Unknown column '' in 'VALUES() function'
 INSERT INTO t2(a,b) VALUES (1,0) ON DUPLICATE KEY UPDATE
 b=(SELECT VALUES(a)+2 FROM t1);
 DROP TABLE t1, t2;
+#
+# MDEV-492: incorrect error check before sending OK in mysql_update 
+#
+CREATE TABLE t1 (a CHAR(3), b BLOB);
+UPDATE t1 SET a = 'new'
+WHERE COLUMN_CREATE( 1, 'v', 1, 'w' ) IS NULL;
+ERROR 22007: Illegal value used as argument of dynamic column function
+drop table t1;

mysql-test/t/errors.test

@@ -85,3 +85,12 @@ INSERT INTO t2 VALUES (1,0) ON DUPLICATE KEY UPDATE
 INSERT INTO t2(a,b) VALUES (1,0) ON DUPLICATE KEY UPDATE
   b=(SELECT VALUES(a)+2 FROM t1);
 DROP TABLE t1, t2;
+
+--echo #
+--echo # MDEV-492: incorrect error check before sending OK in mysql_update 
+--echo #
+CREATE TABLE t1 (a CHAR(3), b BLOB);
+--error ER_DYN_COL_DATA
+UPDATE t1 SET a = 'new'
+WHERE COLUMN_CREATE( 1, 'v', 1, 'w' ) IS NULL;
+drop table t1;

sql/sql_update.cc

@@ -359,7 +359,7 @@ int mysql_update(THD *thd,
   table->file->info(HA_STATUS_VARIABLE | HA_STATUS_NO_LOCK);
 
   select= make_select(table, 0, 0, conds, 0, &error);
-  if (error || !limit ||
+  if (error || !limit || thd->is_error() ||
       (select && select->check_quick(thd, safe_update, limit)))
   {
     delete select;