Bug#37243446: Assertion: item->contextualized in Item::Item

In the patch for bug 36531144, we changed some constructors for
subquery items so that we passed an improved definition text to
their constructors. Unfortunately, the constructors with and without
POS arguments are quite different. Those with a POS argument usually
rely upon a contextualization function to add them to the THD chain
of items, as well as set the contextualized flag. Thus, some special
tests might assert because the contextualized was never set.

The fix here is to add explicit function calls to set the flag.

Change-Id: I6e836bac0beb322b1129d3edeeffc749637120e3

Author: roylyseng

mysql-test/r/subquery_bugs.result

@@ -2459,3 +2459,24 @@ HAVING 1 IN (SELECT min(x.x) FROM (SELECT 1) AS w(w))
 )
 WHERE 1 = 2;
 col
+#
+# Bug#37243446: Assertion: item->contextualized in Item::Item
+#
+CREATE TABLE t (c integer);
+SELECT (SELECT t.c FROM t) AS f FROM t
+UNION ALL
+SELECT 1 FROM t;
+f
+SELECT c IN (SELECT t.c FROM t) AS f FROM t
+UNION ALL
+SELECT 1 FROM t;
+f
+SELECT c >ANY (SELECT t.c FROM t) AS f FROM t
+UNION ALL
+SELECT 1 FROM t;
+f
+SELECT EXISTS (SELECT t.c FROM t) AS f FROM t
+UNION ALL
+SELECT 1 FROM t;
+f
+DROP TABLE t;

mysql-test/t/subquery_bugs.test

@@ -2075,3 +2075,31 @@ FROM (SELECT 1) AS y(y) JOIN (SELECT 1) AS z(z)
          HAVING 1 IN (SELECT min(x.x) FROM (SELECT 1) AS w(w))
         )
 WHERE 1 = 2;
+
+--echo #
+--echo # Bug#37243446: Assertion: item->contextualized in Item::Item
+--echo #
+
+CREATE TABLE t (c integer);
+
+# This crashes:
+SELECT (SELECT t.c FROM t) AS f FROM t
+UNION ALL
+SELECT 1 FROM t;
+
+# This works:
+SELECT c IN (SELECT t.c FROM t) AS f FROM t
+UNION ALL
+SELECT 1 FROM t;
+
+# This works, but does not set contextualized flag
+SELECT c >ANY (SELECT t.c FROM t) AS f FROM t
+UNION ALL
+SELECT 1 FROM t;
+
+# This crashes:
+SELECT EXISTS (SELECT t.c FROM t) AS f FROM t
+UNION ALL
+SELECT 1 FROM t;
+
+DROP TABLE t;

sql/item_subselect.cc

@@ -597,7 +597,9 @@ bool Item_subselect::fix_fields(THD *thd, Item **) {
 
   assert(!fixed);
   assert(indexsubquery_engine == nullptr);
-
+#ifndef NDEBUG
+  assert(contextualized);
+#endif
   if (check_stack_overrun(thd, STACK_MIN_SIZE, (uchar *)&res)) return true;
 
   if (!query_expr()->is_prepared() &&

sql/item_subselect.h

@@ -83,6 +83,16 @@ class Item_subselect : public Item_result_field {
  public:
   Query_expression *query_expr() const { return m_query_expr; }
 
+  /**
+    For Item_subselect constructor with POS parameter, the contextualized
+    field must be transitioned explicitly.
+  */
+  void set_contextualized() {
+#ifndef NDEBUG
+    assert(!contextualized);
+    contextualized = true;
+#endif  // NDEBUG
+  }
   /**
      If !=NO_PLAN_IDX: this Item is in the condition attached to the JOIN_TAB
      having this index in the parent JOIN.

sql/parse_tree_items.cc

@@ -329,6 +329,7 @@ bool PTI_singlerow_subselect::do_itemize(Parse_context *pc, Item **res) {
   *res = new (pc->mem_root) Item_singlerow_subselect(m_pos, subselect->value());
   if (*res == nullptr) return true;
 
+  down_cast<Item_subselect *>(*res)->set_contextualized();
   pc->thd->add_item(*res);
   pc->select->n_scalar_subqueries++;
 
@@ -340,6 +341,7 @@ bool PTI_exists_subselect::do_itemize(Parse_context *pc, Item **res) {
   *res = new (pc->mem_root) Item_exists_subselect(m_pos, subselect->value());
   if (*res == nullptr) return true;
 
+  down_cast<Item_subselect *>(*res)->set_contextualized();
   pc->thd->add_item(*res);
 
   return false;

sql/parse_tree_node_base.h

@@ -230,6 +230,7 @@ class Show_parse_tree {
 template <typename Context>
 class Parse_tree_node_tmpl {
   friend class Item;  // for direct access to the "contextualized" field
+  friend class Item_subselect;
 
   Parse_tree_node_tmpl(const Parse_tree_node_tmpl &);  // undefined
   void operator=(const Parse_tree_node_tmpl &);        // undefined

sql/parser_yystype.h

@@ -125,7 +125,6 @@ class PT_start_option_value_list_following_option_type;
 class PT_sub_partition;
 class PT_subpartition;
 class PT_subquery;
-class PT_subselect;
 class PT_table_constraint_def;
 class PT_table_element;
 class PT_table_reference;
@@ -426,7 +425,6 @@ union MY_SQL_PARSER_STYPE {
   } trg_characteristics;
   Index_hint *key_usage_element;
   List<Index_hint> *key_usage_list;
-  PT_subselect *subselect;
   PT_item_list *item_list2;
   PT_order_expr *order_expr;
   PT_order_list *order_list;

sql/sql_parse.cc

@@ -6672,11 +6672,13 @@ Item *all_any_subquery_creator(THD *thd, const POS &pos, Item *left_expr,
     item = new (thd->mem_root) Item_in_subselect(pos, left_expr, query_block);
     if (item == nullptr) return nullptr;
 
+    down_cast<Item_subselect *>(item)->set_contextualized();
     thd->add_item(item);
   } else if (cmp == &comp_ne_creator && all) {  // <> ALL <=> NOT IN
     item = new Item_in_subselect(pos, left_expr, query_block);
     if (item == nullptr) return nullptr;
 
+    down_cast<Item_subselect *>(item)->set_contextualized();
     thd->add_item(item);
 
     Item *negated = item->truth_transformer(nullptr, Item::BOOL_NEGATED);
@@ -6687,6 +6689,7 @@ Item *all_any_subquery_creator(THD *thd, const POS &pos, Item *left_expr,
         Item_allany_subselect(pos, left_expr, cmp, query_block, all);
     if (it == nullptr) return nullptr;
 
+    it->set_contextualized();
     thd->add_item(it);
 
     if (all) {  // ALL