Bug#52884 mysql-test-run does not work with --debug option

Server crashes on 64bit linux with 'double free or corruption'
message, on 32bit mysql-test-run silently fails on bootstrap
stage. The problem is that FreeState() is called twice
for init_settings struct in _db_end_ function.
The fix is to remove superfluous FreeState() call.
Additional fix:
fixed discrepancy of result file when
debug & valgrind options are enabled
for MTR.

dbug/dbug.c:
  The problem is that FreeState() is called twice
  for init_settings struct in _db_end_ function.
  The fix is to remove superfluous FreeState() call.
mysql-test/r/variables_debug.result:
  fixed discrepancy of result file when
  debug & valgrind options are enabled
  for MTR.
mysql-test/t/variables_debug.test:
  fixed discrepancy of result file when
  debug & valgrind options are enabled
  for MTR.
sql/set_var.cc:
  fixed discrepancy of result file when
  debug & valgrind options are enabled
  for MTR.

1 files changed, 7 insertions, 2 deletions

diff --git a/sql/set_var.cc b/sql/set_var.cc
index f7d9d9df42e..8f0ad93ba43 100644
--- a/sql/set_var.cc
+++ b/sql/set_var.cc
@@ -4239,10 +4239,15 @@ bool sys_var_thd_dbug::check(THD *thd, set_var *var)
 
 bool sys_var_thd_dbug::update(THD *thd, set_var *var)
 {
+  char buf[256];
+  String str(buf, sizeof(buf), system_charset_info), *res;
+
+  res= var->value->val_str(&str);
+
   if (var->type == OPT_GLOBAL)
-    DBUG_SET_INITIAL(var ? var->value->str_value.c_ptr() : "");
+    DBUG_SET_INITIAL(res ? res->c_ptr() : "");
   else
-    DBUG_SET(var ? var->value->str_value.c_ptr() : "");
+    DBUG_SET(res ? res->c_ptr() : "");
 
   return 0;
 }