WSREP: Fix GCC 12.0.1 -Wuninitialized

GCC 12 complains if a reference to an uninitialized object is
being passed to a constructor. The mysql_mutex_t, mysql_cond_t
would be initialized in the constructor body, which is executed
after the initializer list. There is no problem passing a pointer
instead of a reference. The wrapper classes do not dereference
the pointers in the constructor or destructor, so there does not
appear to be any correctness issue.

sql/sql_class.cc

@@ -669,8 +669,8 @@ THD::THD(my_thread_id id, bool is_wsrep_applier)
 
 /* wsrep-lib */
    m_wsrep_next_trx_id(WSREP_UNDEFINED_TRX_ID),
-   m_wsrep_mutex(LOCK_thd_data),
-   m_wsrep_cond(COND_wsrep_thd),
+   m_wsrep_mutex(&LOCK_thd_data),
+   m_wsrep_cond(&COND_wsrep_thd),
    m_wsrep_client_service(this, m_wsrep_client_state),
    m_wsrep_client_state(this,
                         m_wsrep_mutex,

sql/wsrep_condition_variable.h

@@ -26,7 +26,7 @@ class Wsrep_condition_variable : public wsrep::condition_variable
 {
 public:
 
-  Wsrep_condition_variable(mysql_cond_t& cond)
+  Wsrep_condition_variable(mysql_cond_t* cond)
     : m_cond(cond)
   { }
   ~Wsrep_condition_variable()
@@ -34,21 +34,21 @@ class Wsrep_condition_variable : public wsrep::condition_variable
 
   void notify_one()
   {
-    mysql_cond_signal(&m_cond);
+    mysql_cond_signal(m_cond);
   }
 
   void notify_all()
   {
-    mysql_cond_broadcast(&m_cond);
+    mysql_cond_broadcast(m_cond);
   }
 
   void wait(wsrep::unique_lock<wsrep::mutex>& lock)
   {
     mysql_mutex_t* mutex= static_cast<mysql_mutex_t*>(lock.mutex()->native());
-    mysql_cond_wait(&m_cond, mutex);
+    mysql_cond_wait(m_cond, mutex);
   }
 private:
-  mysql_cond_t& m_cond;
+  mysql_cond_t* m_cond;
 };
 
 #endif /* WSREP_CONDITION_VARIABLE_H */

sql/wsrep_mutex.h

@@ -25,26 +25,26 @@
 class Wsrep_mutex : public wsrep::mutex
 {
 public:
-  Wsrep_mutex(mysql_mutex_t& mutex)
+  Wsrep_mutex(mysql_mutex_t* mutex)
     : m_mutex(mutex)
   { }
 
   void lock()
   {
-    mysql_mutex_lock(&m_mutex);
+    mysql_mutex_lock(m_mutex);
   }
 
   void unlock()
   {
-    mysql_mutex_unlock(&m_mutex);
+    mysql_mutex_unlock(m_mutex);
   }
 
   void* native()
   {
-    return &m_mutex;
+    return m_mutex;
   }
 private:
-  mysql_mutex_t& m_mutex;
+  mysql_mutex_t* m_mutex;
 };
 
 #endif /* WSREP_MUTEX_H */

sql/wsrep_server_state.cc

@@ -43,8 +43,8 @@ Wsrep_server_state::Wsrep_server_state(const std::string& name,
                         initial_position,
                         max_protocol_version,
                         wsrep::server_state::rm_sync)
-  , m_mutex(LOCK_wsrep_server_state)
-  , m_cond(COND_wsrep_server_state)
+  , m_mutex(&LOCK_wsrep_server_state)
+  , m_cond(&COND_wsrep_server_state)
   , m_service(*this)
 { }