A fix and a test case for Bug#15683 "crash, Function on nested

VIEWs, Prepared statement": we didn't mark the nested views
as 'prelockng placeholders' when building the prelocking list. 
This resulted in these views being processed (merged, materialized)
before they are actually used. 


mysql-test/r/sp-prelocking.result:
  Test results fixed (Bug#15683)
mysql-test/t/sp-prelocking.test:
  Add a test case for Bug#15683
sql/sql_view.cc:
  When initializing tables used in a view, inherite 
  its 'prelocking_placeholder' flag. This flag is set when we're 
  opening the view in order to build the prelocking list for a query.
  In this case we should only calculate the list to 
  prelock, and should not merge neither this view nor any of the 
  nested views, of there are any. The flag is used to indicate this 
  mode.

mysql-test/r/sp-prelocking.result

@@ -214,3 +214,26 @@ drop function f1;
 drop function f2;
 drop function f3;
 drop procedure sp1;
+drop table if exists t1;
+drop view if exists v1, v2, v3;
+drop function if exists bug15683;
+create table t1 (f1 bigint, f2 varchar(20), f3 bigint);
+insert into t1 set f1 = 1, f2 = 'schoenenbourg', f3 = 1;
+create view v1 as select 1 from t1 union all select 1;
+create view v2 as select 1 from v1;
+create view v3 as select 1 as f1 from v2;
+create function bug15683() returns bigint
+begin
+return (select count(*) from v3);
+end|
+prepare stmt from "select bug15683()";
+execute stmt;
+bug15683()
+2
+execute stmt;
+bug15683()
+2
+deallocate prepare stmt;
+drop table t1;
+drop view v1, v2, v3;
+drop function bug15683;

mysql-test/t/sp-prelocking.test

@@ -241,3 +241,34 @@ drop function f2;
 drop function f3;
 drop procedure sp1;
 
+#
+# Bug#15683 "crash, Function on nested VIEWs, Prepared statement"
+# Check that when creating the prelocking list a nested view 
+# is not merged until it's used.
+#
+--disable_warnings
+drop table if exists t1;
+drop view if exists v1, v2, v3;
+drop function if exists bug15683;
+--enable_warnings
+create table t1 (f1 bigint, f2 varchar(20), f3 bigint);
+insert into t1 set f1 = 1, f2 = 'schoenenbourg', f3 = 1;
+create view v1 as select 1 from t1 union all select 1;
+create view v2 as select 1 from v1;
+create view v3 as select 1 as f1 from v2;
+
+delimiter |;
+create function bug15683() returns bigint
+begin
+return (select count(*) from v3);
+end|
+delimiter ;|
+
+prepare stmt from "select bug15683()";
+execute stmt;
+execute stmt;
+deallocate prepare stmt;
+drop table t1;
+drop view v1, v2, v3;
+drop function bug15683;
+

sql/sql_view.cc

@@ -938,6 +938,7 @@ bool mysql_make_view(THD *thd, File_parser *parser, TABLE_LIST *table)
       tbl->skip_temporary= 1;
       tbl->belong_to_view= top_view;
       tbl->referencing_view= table;
+      tbl->prelocking_placeholder= table->prelocking_placeholder;
       /*
         First we fill want_privilege with SELECT_ACL (this is needed for the
         tables which belongs to view subqueries and temporary table views,