MDEV-5816: Stored programs: validation of stored program statements

Fixed memory leakage taken place on execution of the statement
  SHOW CREATE PACKAGE pkg_name
The memory leak was caused by implementation of sp_compile()
where a mempory root for stored routine was allocated but
a pointer to the new memory root wasn't passed to sp_package::create
for subsequent forwarding to the constructor of sp_package.
Instead, another one mempory root was allocated and the pointer to
the original memroot was missed.

sql/sp_head.cc

@@ -607,14 +607,18 @@ sp_head::sp_head(MEM_ROOT *mem_root_arg, sp_package *parent,
 
 
 sp_package *sp_package::create(LEX *top_level_lex, const sp_name *name,
-                               const Sp_handler *sph)
+                               const Sp_handler *sph, MEM_ROOT *sp_mem_root)
 {
   MEM_ROOT own_root;
-  init_sql_alloc(key_memory_sp_head_main_root, &own_root, MEM_ROOT_BLOCK_SIZE,
-                 MEM_ROOT_PREALLOC, MYF(0));
+  if (!sp_mem_root)
+  {
+    init_sql_alloc(key_memory_sp_head_main_root, &own_root, MEM_ROOT_BLOCK_SIZE,
+                   MEM_ROOT_PREALLOC, MYF(0));
+    sp_mem_root= &own_root;
+  }
   sp_package *sp;
-  if (!(sp= new (&own_root) sp_package(&own_root, top_level_lex, name, sph)))
-    free_root(&own_root, MYF(0));
+  if (!(sp= new (sp_mem_root) sp_package(sp_mem_root, top_level_lex, name, sph)))
+    free_root(sp_mem_root, MYF(0));
 
   return sp;
 }

sql/sp_head.h

@@ -1062,7 +1062,7 @@ class sp_package: public sp_head
   ~sp_package();
 public:
   static sp_package *create(LEX *top_level_lex, const sp_name *name,
-                            const Sp_handler *sph);
+                            const Sp_handler *sph, MEM_ROOT *sp_mem_root);
 
   bool add_routine_declaration(LEX *lex)
   {

sql/sql_lex.cc

@@ -9397,7 +9397,8 @@ sp_package *LEX::create_package_start(THD *thd,
       return 0;
     }
   }
-  if (unlikely(!(pkg= sp_package::create(this, name_arg, sph))))
+  if (unlikely(!(pkg= sp_package::create(this, name_arg, sph,
+                                         sp_mem_root_ptr))))
     return NULL;
   pkg->reset_thd_mem_root(thd);
   pkg->init(this);