Bug#32820437: FULLTEXT MATCH CRASHED THE SERVER

Chaithra Gopalareddy · dahlerlend · commit ca4d2ffa440a · 2021-06-21T09:33:37.000+02:00
When a condition is pushed down to a materialized derived
table, a clone of the derived table expression replaces
the field (from the outer query block) in the condition.
If this cloned item has a fulltext function, it needs to
be added to the ftfunc_list in the derived table query block.
However, while cloning, as the query block is not
set to the derived table query block, the fulltext function
gets added to the outer query block leading to problems
later.

Solution:
We now use derived query block to clone an item.

Change-Id: Id23e2bda8673e52a58805a48c6578aa1db5fc913
diff --git a/sql/sql_derived.cc b/sql/sql_derived.cc
@@ -562,6 +562,10 @@ Item *TABLE_LIST::get_clone_for_derived_expr(THD *thd, Item *item,
   bool parsing_system_view_saved = thd->parsing_system_view;
   thd->parsing_system_view = is_system_view;
 
+  // Set the correct query block to parse the item. In some cases, like
+  // fulltext functions, parser needs to add them to ftfunc_list of the
+  // query block.
+  thd->lex->set_current_query_block(context->query_block);
   bool result = parse_sql(thd, &parser_state, nullptr);
 
   // End of parsing.
