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

@@ -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,