Fixed bug#11753738 (formely known as bug#45235) - 5.1 DOES NOT SUPPORT 5.0-ONLY

SYNTAX TRIGGERS IN ANY WAY

Table with triggers which were using deprecated (5.0-only) syntax became
unavailable for any DML and DDL after upgrade to 5.1 version of server.
Attempt to execute any statement on such a table resulted in parsing
error reported. Since this included DROP TRIGGER and DROP TABLE
statements (actually, the latter was allowed but was not functioning
properly for such tables) it was impossible to fix the problem without
manual operations on .TRG and .TRN files in data directory.

The problem was that failure to parse trigger body (due to 5.0-only
syntax) when opening trigger file for a table prevented the table
from being open. This made all operations on the table impossible
(except DROP TABLE which due to peculiarity in its implementation
dropped the table but left trigger files around).

This patch solves this problem by silencing error which occurs when
we parse trigger body during table open. Error message is preserved
for the future use and table is marked as having a broken trigger.
We also try to analyze parse tree to recover trigger name, which
will be needed in order to drop the broken trigger. DML statements
which invoke triggers on the table marked as having broken trigger
are prohibited and emit saved error message. The same happens for
DDL which change triggers except DROP TRIGGER and DROP TABLE which
try their best to do what was requested. Table becomes no longer
marked as having broken trigger when last such trigger is dropped.

mysql-test/r/trigger-compat.result:
  Add results for test case for bug#45235
mysql-test/t/trigger-compat.test:
  Add test case for bug#45235.
sql/sp_head.cc:
  Added protection against MEM_ROOT double restoring to
  sp_head::restore_thd_mem_root() method. Since this
  method can be sometimes called twice during parsing
  of stored routine (the first time during normal flow
  of parsing, and the second time when a syntax error
  is detected) we need to shortcut execution of the
  method to avoid damaging MEM_ROOT by the second
  consecutive call to this method.
sql/sql_trigger.cc:
  Added error handler Deprecated_trigger_syntax_handler to 
  catch non-OOM errors during parsing of trigger body.
  
  Added handling of parse errors into method 
  Table_triggers_list::check_n_load().
sql/sql_trigger.h:
  Added new members to handle broken triggers and error messages.

3 files changed, 273 insertions, 3 deletions

diff --git a/mysql-test/r/trigger-compat.result b/mysql-test/r/trigger-compat.result
index 2bcd919e0db..d456ce8253f 100644
--- a/mysql-test/r/trigger-compat.result
+++ b/mysql-test/r/trigger-compat.result
@@ -43,3 +43,101 @@ DROP TABLE t2;
 DROP USER mysqltest_dfn@localhost;
 DROP USER mysqltest_inv@localhost;
 DROP DATABASE mysqltest_db1;
+USE test;
+#
+# Bug#45235: 5.1 does not support 5.0-only syntax triggers in any way
+#
+DROP TABLE IF EXISTS t1, t2, t3;
+CREATE TABLE t1 ( a INT );
+CREATE TABLE t2 ( a INT );
+CREATE TABLE t3 ( a INT );
+INSERT INTO t1 VALUES (1), (2), (3);
+INSERT INTO t2 VALUES (1), (2), (3);
+INSERT INTO t3 VALUES (1), (2), (3);
+# We simulate importing a trigger from 5.0 by writing a .TRN file for
+# each trigger plus a .TRG file the way MySQL 5.0 would have done it, 
+# with syntax allowed in 5.0 only.
+#
+# Note that in 5.0 the following lines are missing from t1.TRG:
+#
+# client_cs_names='latin1'
+# connection_cl_names='latin1_swedish_ci'
+# db_cl_names='latin1_swedish_ci'
+# We will get parse errors for most DDL and DML statements when the table
+# has broken triggers. The parse error refers to the first broken 
+# trigger.
+CREATE TRIGGER tr16 AFTER UPDATE ON t1 FOR EACH ROW INSERT INTO t1 VALUES (1);
+ERROR 42000: Trigger 'tr13' has an error in its body: 'You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'a USING t1 a' at line 1'
+CREATE TRIGGER tr22 BEFORE INSERT ON t2 FOR EACH ROW DELETE FROM non_existing_table;
+ERROR 42000: Unknown trigger has an error in its body: 'You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'Not allowed syntax here, and trigger name cant be extracted either.' at line 1'
+SHOW TRIGGERS;
+Trigger	Event	Table	Statement	Timing	Created	sql_mode	Definer	character_set_client	collation_connection	Database Collation
+tr11	INSERT	t1	DELETE FROM t3	BEFORE	NULL		root@localhost	latin1	latin1_swedish_ci	latin1_swedish_ci
+tr12	INSERT	t1	DELETE FROM t3	AFTER	NULL		root@localhost	latin1	latin1_swedish_ci	latin1_swedish_ci
+tr14	DELETE	t1	DELETE FROM non_existing_table	AFTER	NULL		root@localhost	latin1	latin1_swedish_ci	latin1_swedish_ci
+Warnings:
+Warning	1603	Triggers for table `test`.`t1` have no creation context
+Warning	1603	Triggers for table `test`.`t2` have no creation context
+INSERT INTO t1 VALUES (1);
+ERROR 42000: Trigger 'tr13' has an error in its body: 'You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'a USING t1 a' at line 1'
+INSERT INTO t2 VALUES (1);
+ERROR 42000: Unknown trigger has an error in its body: 'You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'Not allowed syntax here, and trigger name cant be extracted either.' at line 1'
+DELETE FROM t1;
+ERROR 42000: Trigger 'tr13' has an error in its body: 'You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'a USING t1 a' at line 1'
+UPDATE t1 SET a = 1 WHERE a = 1;
+ERROR 42000: Trigger 'tr13' has an error in its body: 'You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'a USING t1 a' at line 1'
+SELECT * FROM t1;
+a
+1
+2
+3
+RENAME TABLE t1 TO t1_2;
+ERROR 42000: Trigger 'tr13' has an error in its body: 'You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'a USING t1 a' at line 1'
+SHOW TRIGGERS;
+Trigger	Event	Table	Statement	Timing	Created	sql_mode	Definer	character_set_client	collation_connection	Database Collation
+tr11	INSERT	t1	DELETE FROM t3	BEFORE	NULL		root@localhost	latin1	latin1_swedish_ci	latin1_swedish_ci
+tr12	INSERT	t1	DELETE FROM t3	AFTER	NULL		root@localhost	latin1	latin1_swedish_ci	latin1_swedish_ci
+tr14	DELETE	t1	DELETE FROM non_existing_table	AFTER	NULL		root@localhost	latin1	latin1_swedish_ci	latin1_swedish_ci
+Warnings:
+Warning	1603	Triggers for table `test`.`t1` have no creation context
+DROP TRIGGER tr11;
+Warnings:
+Warning	1603	Triggers for table `test`.`t1` have no creation context
+DROP TRIGGER tr12;
+DROP TRIGGER tr13;
+DROP TRIGGER tr14;
+DROP TRIGGER tr15;
+SHOW TRIGGERS;
+Trigger	Event	Table	Statement	Timing	Created	sql_mode	Definer	character_set_client	collation_connection	Database Collation
+# Make sure there is no trigger file left.
+# We write the same trigger files one more time to test DROP TABLE.
+DROP TABLE t1;
+Warnings:
+Warning	1603	Triggers for table `test`.`t1` have no creation context
+DROP TABLE t2;
+Warnings:
+Warning	1603	Triggers for table `test`.`t2` have no creation context
+DROP TABLE t3;
+# Make sure there is no trigger file left.
+CREATE TABLE t1 ( a INT );
+CREATE TABLE t2 ( a INT );
+INSERT INTO t1 VALUES (1), (2), (3);
+INSERT INTO t2 VALUES (1), (2), (3);
+# We write three trigger files. First trigger is syntaxically incorrect, next trigger is correct
+# and last trigger is broken.
+# Next we try to execute SHOW CREATE TRGGIR command for broken trigger and then try to drop one.
+FLUSH TABLE t1;
+SHOW CREATE TRIGGER tr12;
+Trigger	sql_mode	SQL Original Statement	character_set_client	collation_connection	Database Collation
+tr12		CREATE DEFINER=`root`@`localhost` TRIGGER tr12 BEFORE INSERT ON t1 FOR EACH ROW DELETE FROM t2	latin1	latin1_swedish_ci	latin1_swedish_ci
+Warnings:
+Warning	1603	Triggers for table `test`.`t1` have no creation context
+SHOW CREATE TRIGGER tr11;
+Trigger	sql_mode	SQL Original Statement	character_set_client	collation_connection	Database Collation
+tr11		CREATE DEFINER=`root`@`localhost` TRIGGER tr11 BEFORE DELETE ON t1 FOR EACH ROW DELETE FROM t1 a USING t1 a	latin1	latin1_swedish_ci	latin1_swedish_ci
+DROP TRIGGER tr12;
+Warnings:
+Warning	1603	Triggers for table `test`.`t1` have no creation context
+DROP TRIGGER tr11;
+DROP TABLE t1;
+DROP TABLE t2;
diff --git a/mysql-test/r/trigger.result b/mysql-test/r/trigger.result
index 16b165cdc11..3d7ef5f34bd 100644
--- a/mysql-test/r/trigger.result
+++ b/mysql-test/r/trigger.result
@@ -2134,10 +2134,8 @@ CREATE TRIGGER trg1 BEFORE INSERT ON t2 FOR EACH ROW INSERT/*!INTO*/t1 VALUES (1
 # Used to crash
 SHOW TRIGGERS IN db1;
 Trigger	Event	Table	Statement	Timing	Created	sql_mode	Definer	character_set_client	collation_connection	Database Collation
-Warnings:
-Warning	1064	You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'VALUES (1)' at line 1
 INSERT INTO t2 VALUES (1);
-ERROR 42000: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'VALUES (1)' at line 1
+ERROR 42000: Trigger 'trg1' has an error in its body: 'You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'VALUES (1)' at line 1'
 SELECT * FROM t1;
 b
 # Work around Bug#45235
diff --git a/mysql-test/t/trigger-compat.test b/mysql-test/t/trigger-compat.test
index 2cc86692d0d..216e64f8543 100644
--- a/mysql-test/t/trigger-compat.test
+++ b/mysql-test/t/trigger-compat.test
@@ -106,4 +106,178 @@ DROP TABLE t2;
 DROP USER mysqltest_dfn@localhost;
 DROP USER mysqltest_inv@localhost;
 DROP DATABASE mysqltest_db1;
+USE test;
 
+
+--echo #
+--echo # Bug#45235: 5.1 does not support 5.0-only syntax triggers in any way
+--echo #
+let $MYSQLD_DATADIR=`SELECT @@datadir`;
+
+--disable_warnings
+DROP TABLE IF EXISTS t1, t2, t3;
+--enable_warnings
+
+CREATE TABLE t1 ( a INT );
+CREATE TABLE t2 ( a INT );
+CREATE TABLE t3 ( a INT );
+INSERT INTO t1 VALUES (1), (2), (3);
+INSERT INTO t2 VALUES (1), (2), (3);
+INSERT INTO t3 VALUES (1), (2), (3);
+
+--echo # We simulate importing a trigger from 5.0 by writing a .TRN file for
+--echo # each trigger plus a .TRG file the way MySQL 5.0 would have done it, 
+--echo # with syntax allowed in 5.0 only.
+--echo #
+--echo # Note that in 5.0 the following lines are missing from t1.TRG:
+--echo #
+--echo # client_cs_names='latin1'
+--echo # connection_cl_names='latin1_swedish_ci'
+--echo # db_cl_names='latin1_swedish_ci'
+
+--write_file $MYSQLD_DATADIR/test/tr11.TRN
+TYPE=TRIGGERNAME
+trigger_table=t1
+EOF
+
+--write_file $MYSQLD_DATADIR/test/tr12.TRN
+TYPE=TRIGGERNAME
+trigger_table=t1
+EOF
+
+--write_file $MYSQLD_DATADIR/test/tr13.TRN
+TYPE=TRIGGERNAME
+trigger_table=t1
+EOF
+
+--write_file $MYSQLD_DATADIR/test/tr14.TRN
+TYPE=TRIGGERNAME
+trigger_table=t1
+EOF
+
+--write_file $MYSQLD_DATADIR/test/tr15.TRN
+TYPE=TRIGGERNAME
+trigger_table=t1
+EOF
+
+--write_file $MYSQLD_DATADIR/test/t1.TRG
+TYPE=TRIGGERS
+triggers='CREATE DEFINER=`root`@`localhost` TRIGGER tr11 BEFORE INSERT ON t1 FOR EACH ROW DELETE FROM t3' 'CREATE DEFINER=`root`@`localhost` TRIGGER tr12 AFTER INSERT ON t1 FOR EACH ROW DELETE FROM t3' 'CREATE DEFINER=`root`@`localhost` TRIGGER tr13 BEFORE DELETE ON t1 FOR EACH ROW DELETE FROM t1 a USING t1 a' 'CREATE DEFINER=`root`@`localhost` TRIGGER tr14 AFTER DELETE ON t1 FOR EACH ROW DELETE FROM non_existing_table' 'CREATE DEFINER=`root`@`localhost` TRIGGER tr15 BEFORE UPDATE ON t1 FOR EACH ROW DELETE FROM non_existing_table a USING non_existing_table a'
+sql_modes=0 0 0 0 0
+definers='root@localhost' 'root@localhost' 'root@localhost' 'root@localhost' 'root@localhost'
+EOF
+
+--write_file $MYSQLD_DATADIR/test/t2.TRG
+TYPE=TRIGGERS
+triggers='Not allowed syntax here, and trigger name cant be extracted either.'
+sql_modes=0
+definers='root@localhost'
+EOF
+
+--echo # We will get parse errors for most DDL and DML statements when the table
+--echo # has broken triggers. The parse error refers to the first broken 
+--echo # trigger.
+--error ER_PARSE_ERROR
+CREATE TRIGGER tr16 AFTER UPDATE ON t1 FOR EACH ROW INSERT INTO t1 VALUES (1);
+--error ER_PARSE_ERROR
+CREATE TRIGGER tr22 BEFORE INSERT ON t2 FOR EACH ROW DELETE FROM non_existing_table;
+SHOW TRIGGERS;
+--error ER_PARSE_ERROR
+INSERT INTO t1 VALUES (1);
+--error ER_PARSE_ERROR
+INSERT INTO t2 VALUES (1);
+--error ER_PARSE_ERROR
+DELETE FROM t1;
+--error ER_PARSE_ERROR
+UPDATE t1 SET a = 1 WHERE a = 1;
+SELECT * FROM t1;
+--error ER_PARSE_ERROR
+RENAME TABLE t1 TO t1_2;
+SHOW TRIGGERS;
+
+DROP TRIGGER tr11;
+DROP TRIGGER tr12;
+DROP TRIGGER tr13;
+DROP TRIGGER tr14;
+DROP TRIGGER tr15;
+
+SHOW TRIGGERS;
+
+--echo # Make sure there is no trigger file left.
+--list_files $MYSQLD_DATADIR/test/ tr*
+
+--echo # We write the same trigger files one more time to test DROP TABLE.
+--write_file $MYSQLD_DATADIR/test/tr11.TRN
+TYPE=TRIGGERNAME
+trigger_table=t1
+EOF
+
+--write_file $MYSQLD_DATADIR/test/tr12.TRN
+TYPE=TRIGGERNAME
+trigger_table=t1
+EOF
+
+--write_file $MYSQLD_DATADIR/test/tr13.TRN
+TYPE=TRIGGERNAME
+trigger_table=t1
+EOF
+
+--write_file $MYSQLD_DATADIR/test/tr14.TRN
+TYPE=TRIGGERNAME
+trigger_table=t1
+EOF
+
+--write_file $MYSQLD_DATADIR/test/tr15.TRN
+TYPE=TRIGGERNAME
+trigger_table=t1
+EOF
+
+--write_file $MYSQLD_DATADIR/test/t1.TRG
+TYPE=TRIGGERS
+triggers='CREATE DEFINER=`root`@`localhost` TRIGGER tr11 BEFORE INSERT ON t1 FOR EACH ROW DELETE FROM t3' 'CREATE DEFINER=`root`@`localhost` TRIGGER tr12 AFTER INSERT ON t1 FOR EACH ROW DELETE FROM t3' 'CREATE DEFINER=`root`@`localhost` TRIGGER tr13 BEFORE DELETE ON t1 FOR EACH ROW DELETE FROM t1 a USING t1 a' 'CREATE DEFINER=`root`@`localhost` TRIGGER tr14 AFTER DELETE ON t1 FOR EACH ROW DELETE FROM non_existing_table' 'CREATE DEFINER=`root`@`localhost` TRIGGER tr15 BEFORE UPDATE ON t1 FOR EACH ROW DELETE FROM non_existing_table a USING non_existing_table a'
+sql_modes=0 0 0 0 0
+definers='root@localhost' 'root@localhost' 'root@localhost' 'root@localhost' 'root@localhost'
+EOF
+
+DROP TABLE t1;
+DROP TABLE t2;
+DROP TABLE t3;
+
+--echo # Make sure there is no trigger file left.
+
+--list_files $MYSQLD_DATADIR/test/ tr*
+
+CREATE TABLE t1 ( a INT );
+CREATE TABLE t2 ( a INT );
+INSERT INTO t1 VALUES (1), (2), (3);
+INSERT INTO t2 VALUES (1), (2), (3);
+
+--echo # We write three trigger files. First trigger is syntaxically incorrect, next trigger is correct
+--echo # and last trigger is broken.
+--echo # Next we try to execute SHOW CREATE TRGGIR command for broken trigger and then try to drop one.
+--write_file $MYSQLD_DATADIR/test/tr11.TRN
+TYPE=TRIGGERNAME
+trigger_table=t1
+EOF
+
+--write_file $MYSQLD_DATADIR/test/tr12.TRN
+TYPE=TRIGGERNAME
+trigger_table=t1
+EOF
+
+--write_file $MYSQLD_DATADIR/test/t1.TRG
+TYPE=TRIGGERS
+triggers='CREATE the wrongest trigger_in_the_world' 'CREATE DEFINER=`root`@`localhost` TRIGGER tr11 BEFORE DELETE ON t1 FOR EACH ROW DELETE FROM t1 a USING t1 a' 'CREATE DEFINER=`root`@`localhost` TRIGGER tr12 BEFORE INSERT ON t1 FOR EACH ROW DELETE FROM t2'
+sql_modes=0 0 0
+definers='root@localhost' 'root@localhost' 'root@localhost'
+EOF
+
+FLUSH TABLE t1;
+
+SHOW CREATE TRIGGER tr12;
+SHOW CREATE TRIGGER tr11;
+DROP TRIGGER tr12;
+DROP TRIGGER tr11;
+
+DROP TABLE t1;
+DROP TABLE t2;