Bug#34424 query_cache_debug.test leads to valgrind warnings

Bug#34678 @@debug variable's incremental mode

The problem is that the per-thread debugging settings stack wasn't
being deallocated before the thread termination, leaking the stack
memory. The chosen solution is to push a new state if the current
is set to the initial settings and pop it (free) once the thread
finishes.


dbug/dbug.c:
  Move dbug parser out of _db_set_ to a separate function and
  make _db_set_ push a new stack if the corrent one is set to
  the initial settings.
dbug/user.r:
  Update DBUG_SET description.
mysql-test/t/disabled.def:
  Re-enable test case which triggered the leak.
mysys/my_thr_init.c:
  Pop a pushed state, nop if stack is empty.
sql/set_var.cc:
  Handle incremental debug settings.
mysql-test/r/variables_debug.result:
  Add new test case result for Bug#34678
mysql-test/t/variables_debug.test:
  Add new test case for Bug#34678

1 files changed, 12 insertions, 0 deletions

diff --git a/mysql-test/t/variables_debug.test b/mysql-test/t/variables_debug.test
new file mode 100644
index 00000000000..7dcaf246803
--- /dev/null
+++ b/mysql-test/t/variables_debug.test
@@ -0,0 +1,12 @@
+--source include/have_debug.inc
+
+#
+# Bug#34678 @@debug variable's incremental mode
+#
+
+set debug= 'T';
+select @@debug;
+set debug= '+P';
+select @@debug;
+set debug= '-P';
+select @@debug;