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

2 files changed, 38 insertions, 12 deletions

diff --git a/dbug/dbug.c b/dbug/dbug.c
index 7f4292d18b1..666ab2b3e3c 100644
--- a/dbug/dbug.c
+++ b/dbug/dbug.c
@@ -412,15 +412,11 @@ void _db_process_(const char *name)
   cs->process= name;
 }
 
+
 /*
  *  FUNCTION
  *
- *      _db_set_       set current debugger settings
- *
- *  SYNOPSIS
- *
- *      VOID _db_set_(control)
- *      char *control;
+ *      DbugParse       parse control string and set current debugger setting
  *
  *  DESCRIPTION
  *
@@ -444,7 +440,7 @@ void _db_process_(const char *name)
  *
  */
 
-void _db_set_(CODE_STATE *cs, const char *control)
+static void DbugParse(CODE_STATE *cs, const char *control)
 {
   const char *end;
   int rel=0;
@@ -674,6 +670,35 @@ void _db_set_(CODE_STATE *cs, const char *control)
 /*
  *  FUNCTION
  *
+ *      _db_set_       set current debugger settings
+ *
+ *  SYNOPSIS
+ *
+ *      VOID _db_set_(control)
+ *      char *control;
+ *
+ *  DESCRIPTION
+ *
+ *      Given pointer to a debug control string in "control",
+ *      parses the control string, and sets up a current debug
+ *      settings. Pushes a new debug settings if the current is
+ *      set to the initial debugger settings.
+ */
+
+void _db_set_(CODE_STATE *cs, const char *control)
+{
+  get_code_state_or_return;
+
+  if (cs->stack == &init_settings)
+    PushState(cs);
+
+  DbugParse(cs, control);
+}
+
+
+/*
+ *  FUNCTION
+ *
  *      _db_push_       push current debugger settings and set up new one
  *
  *  SYNOPSIS
@@ -685,7 +710,7 @@ void _db_set_(CODE_STATE *cs, const char *control)
  *
  *      Given pointer to a debug control string in "control", pushes
  *      the current debug settings, parses the control string, and sets
- *      up a new debug settings with _db_set_()
+ *      up a new debug settings with DbugParse()
  *
  */
 
@@ -694,7 +719,7 @@ void _db_push_(const char *control)
   CODE_STATE *cs=0;
   get_code_state_or_return;
   PushState(cs);
-  _db_set_(cs, control);
+  DbugParse(cs, control);
 }
 
 /*
@@ -717,7 +742,7 @@ void _db_set_init_(const char *control)
   CODE_STATE tmp_cs;
   bzero((uchar*) &tmp_cs, sizeof(tmp_cs));
   tmp_cs.stack= &init_settings;
-  _db_set_(&tmp_cs, control);
+  DbugParse(&tmp_cs, control);
 }
 
 /*
diff --git a/dbug/user.r b/dbug/user.r
index e41367de321..19de840d0ad 100644
--- a/dbug/user.r
+++ b/dbug/user.r
@@ -730,8 +730,9 @@ warning will be given.  The DBUG_POP macro has no arguments.
 EX:\ \fCDBUG_POP\ ();\fR
 .SP 1
 .LI DBUG_SET\ 
-Modifies the current debugger state on top of the stack using the
-debug control string passed as the macro argument.  Unless
+Modifies the current debugger state on top of the stack or pushes
+a new state if the current is set to the initial settings, using
+the debug control string passed as the macro argument.  Unless
 .I incremental
 control string is used (see below), it's equivalent to a combination of
 DBUG_POP and DBUG_PUSH.