MDEV-6152: Remove calls to current_thd while creating Item

- Part 4: Removing calls to sql_alloc() and sql_calloc()

Other things:
- Added current_thd in some places to make it clear that it's called (easier to remove later)
- Move memory allocation from Item_func_case::fix_length_and_dec() to Item_func_case::fix_fields()
- Added mem_root to some new calls
- Fixed some wrong UNINIT_VAR() calls
- Fixed a bug in generate_partition_syntax() in case of errors
- Added mem_root to argument to new thread_info
- Simplified my_parse_error() call in sql_yacc.yy

1 files changed, 3 insertions, 3 deletions

diff --git a/sql/item_sum.cc b/sql/item_sum.cc
index 0eff2b6cec9..b67986f0fb0 100644
--- a/sql/item_sum.cc
+++ b/sql/item_sum.cc
@@ -404,7 +404,7 @@ bool Item_sum::collect_outer_ref_processor(uchar *param)
 Item_sum::Item_sum(THD *thd, List<Item> &list): Item_func_or_sum(thd, list),
   forced_const(FALSE)
 {
-  if (!(orig_args= (Item **) sql_alloc(sizeof(Item *) * arg_count)))
+  if (!(orig_args= (Item **) thd->alloc(sizeof(Item *) * arg_count)))
   {
     args= NULL;
   }
@@ -3197,8 +3197,8 @@ Item_func_group_concat(THD *thd, Name_resolution_context *context_arg,
            (for possible order items in temporary tables)
     order - arg_count_order
   */
-  if (!(args= (Item**) sql_alloc(sizeof(Item*) * arg_count * 2 +
-                                 sizeof(ORDER*)*arg_count_order)))
+  if (!(args= (Item**) thd->alloc(sizeof(Item*) * arg_count * 2 +
+                                  sizeof(ORDER*)*arg_count_order)))
     return;
 
   order= (ORDER**)(args + arg_count);