MDEV-11129 CREATE OR REPLACE TABLE t1 AS SELECT spfunc() crashes if spfunc() references t1

Fixed by extending unique_table() with a flag to not allow usage of
the replaced table.

I also cleaned up find_dup_table() to not use goto next.
I also added more comments to the code in find_dup_table()

1 files changed, 25 insertions, 0 deletions

diff --git a/mysql-test/t/create_or_replace.test b/mysql-test/t/create_or_replace.test
index b37417f39d0..5ebb3031be3 100644
--- a/mysql-test/t/create_or_replace.test
+++ b/mysql-test/t/create_or_replace.test
@@ -398,3 +398,28 @@ CREATE OR REPLACE TABLE t1 AS SELECT f1();
 UNLOCK TABLES;
 DROP FUNCTION f1;
 DROP TABLE t1;
+
+--echo #
+--echo # MDEV-11129
+--echo # CREATE OR REPLACE TABLE t1 AS SELECT spfunc() crashes if spfunc()
+--echo # references t1
+--echo #
+
+CREATE OR REPLACE TABLE t1(a INT);
+DELIMITER $$;
+CREATE FUNCTION f1() RETURNS VARCHAR(16383)
+BEGIN
+  INSERT INTO t1 VALUES(1);
+  RETURN 'test';
+END;
+$$
+DELIMITER ;$$
+--error ER_UPDATE_TABLE_USED
+CREATE OR REPLACE TABLE t1 AS SELECT f1();
+LOCK TABLE t1 WRITE;
+--error ER_TABLE_NOT_LOCKED
+CREATE OR REPLACE TABLE t1 AS SELECT f1();
+UNLOCK TABLES;
+
+DROP FUNCTION f1;
+DROP TABLE t1;