Fixed LP bug #784281.

When a view is merged into a select all the depended_from fields
pointing to the select of the view should have been corrected to
point to the select where the view is used. It was not done yet.
This could lead to wrong results returned by queries such as
one from the test case for bug 33389.
Correction of outer references required walking through all items
of the proccesed qurery. To avoid this the following solution was
implemented.
Each select now contains a pointer to the select it is merged into
(if there is any). Such pointers allow to get the corrected value
of depended_from on the fly. The function Item_ident::get_depended_from
was introduced for this purpose.

1 files changed, 52 insertions, 8 deletions

diff --git a/sql/item.cc b/sql/item.cc
index 0660ea4fd41..eb38ee2e30b 100644
--- a/sql/item.cc
+++ b/sql/item.cc
@@ -652,7 +652,7 @@ void Item_ident::cleanup()
 bool Item_ident::remove_dependence_processor(uchar * arg)
 {
   DBUG_ENTER("Item_ident::remove_dependence_processor");
-  if (depended_from == (st_select_lex *) arg)
+  if (get_depended_from() == (st_select_lex *) arg)
     depended_from= 0;
   context= &((st_select_lex *) arg)->context;
   DBUG_RETURN(0);
@@ -2292,17 +2292,17 @@ table_map Item_field::used_tables() const
 {
   if (field->table->const_table)
     return 0;					// const item
-  return (depended_from ? OUTER_REF_TABLE_BIT : field->table->map);
+  return (get_depended_from() ? OUTER_REF_TABLE_BIT : field->table->map);
 }
 
 table_map Item_field::all_used_tables() const
 {
-  return (depended_from ? OUTER_REF_TABLE_BIT : field->table->map);
+  return (get_depended_from() ? OUTER_REF_TABLE_BIT : field->table->map);
 }
 
 void Item_field::fix_after_pullout(st_select_lex *new_parent, Item **ref)
 {
-  if (new_parent == depended_from)
+  if (new_parent == get_depended_from())
     depended_from= NULL;
   Name_resolution_context *ctx= new Name_resolution_context();
   ctx->outer_context= NULL; // We don't build a complete name resolver
@@ -6299,8 +6299,9 @@ bool Item_ref::fix_fields(THD *thd, Item **reference)
   {
     if (depended_from && reference)
     {
-      DBUG_ASSERT(context->select_lex != depended_from);
-      context->select_lex->register_dependency_item(depended_from, reference);
+      DBUG_ASSERT(context->select_lex != get_depended_from());
+      context->select_lex->register_dependency_item(get_depended_from(),
+                                                    reference);
     }
     /*
       It could be that we're referring to something that's in ancestor selects.
@@ -7260,7 +7261,7 @@ bool Item_outer_ref::fix_fields(THD *thd, Item **reference)
 
 void Item_outer_ref::fix_after_pullout(st_select_lex *new_parent, Item **ref)
 {
-  if (depended_from == new_parent)
+  if (get_depended_from() == new_parent)
   {
     *ref= outer_ref;
     (*ref)->fix_after_pullout(new_parent, ref);
@@ -7270,7 +7271,7 @@ void Item_outer_ref::fix_after_pullout(st_select_lex *new_parent, Item **ref)
 void Item_ref::fix_after_pullout(st_select_lex *new_parent, Item **refptr)
 {
   (*ref)->fix_after_pullout(new_parent, ref);
-  if (depended_from == new_parent)
+  if (get_depended_from() == new_parent)
     depended_from= NULL;
 }
 
@@ -8860,6 +8861,49 @@ void view_error_processor(THD *thd, void *data)
   ((TABLE_LIST *)data)->hide_view_error(thd);
 }
 
+
+inline struct st_select_lex *Item_ident::get_depended_from() const
+{
+  st_select_lex *dep;
+  if ((dep= depended_from))
+    for ( ; dep->merged_into; dep= dep->merged_into);
+  return dep;
+}
+
+
+table_map Item_ref::used_tables() const		
+{
+  return get_depended_from() ? OUTER_REF_TABLE_BIT : (*ref)->used_tables(); 
+}
+
+
+void Item_ref::update_used_tables() 
+{ 
+  if (!get_depended_from())
+    (*ref)->update_used_tables(); 
+}
+
+
+table_map Item_direct_view_ref::used_tables() const		
+{
+  return get_depended_from() ? 
+         OUTER_REF_TABLE_BIT :
+         (view->merged ? (*ref)->used_tables() : view->table->map); 
+}
+
+
+/*
+  we add RAND_TABLE_BIT to prevent moving this item from HAVING to WHERE
+*/
+table_map Item_ref_null_helper::used_tables() const
+{
+  return (get_depended_from() ?
+          OUTER_REF_TABLE_BIT :
+          (*ref)->used_tables() | RAND_TABLE_BIT);
+}
+
+
+
 /*****************************************************************************
 ** Instantiate templates
 *****************************************************************************/