Fix for bug #24117 "server crash on a FETCH with a cursor on a table which is not in the table cache"

Problem:
When creating a temporary field for a temporary table in create_tmp_field_from_field(), a resulting field is created as an exact copy of an original one (in Field::new_field()). However, Field_enum and Field_set contain a pointer (typelib) to memory allocated in the parent table's MEM_ROOT, which under some circumstances may be deallocated later by the time a temporary table is used.

Solution:
Override the new_field() method for Field_enum and Field_set and create a separate copy of the typelib structure in there.


include/typelib.h:
  Added copy_typelib() declaration
mysql-test/r/sp.result:
  Added a testcase for bug #24117 "server crash on a FETCH with a cursor on a table which is not in the table cache"
mysql-test/t/sp.test:
  Added a testcase for bug #24117 "server crash on a FETCH with a cursor on a table which is not in the table cache"
mysys/typelib.c:
  Added copy_typelib() definition
sql/field.cc:
  Create a copy of the internal 'typelib' structure when copying Field_enum of Field_set objects.
sql/field.h:
  Override new_field method in Field_enum (and Field_set) to copy the typelib structure.

1 files changed, 16 insertions, 0 deletions

diff --git a/mysql-test/r/sp.result b/mysql-test/r/sp.result
index 9db4325aea2..793abb417fb 100644
--- a/mysql-test/r/sp.result
+++ b/mysql-test/r/sp.result
@@ -5708,4 +5708,20 @@ DROP TABLE bug23760, bug23760_log|
 DROP PROCEDURE bug23760_update_log|
 DROP PROCEDURE bug23760_test_row_count|
 DROP FUNCTION bug23760_rc_test|
+DROP PROCEDURE IF EXISTS bug24117|
+DROP TABLE IF EXISTS t3|
+CREATE TABLE t3(c1 ENUM('abc'))|
+INSERT INTO t3 VALUES('abc')|
+CREATE PROCEDURE bug24117()
+BEGIN
+DECLARE t3c1 ENUM('abc');
+DECLARE mycursor CURSOR FOR SELECT c1 FROM t3;
+OPEN mycursor;
+FLUSH TABLES;
+FETCH mycursor INTO t3c1;
+CLOSE mycursor;
+END|
+CALL bug24117()|
+DROP PROCEDURE bug24117|
+DROP TABLE t3|
 drop table t1,t2;