A fix and test case for Bug#6102 "Server crash with prepared statement

and blank after function name".
Crop fruits of copy-paste programming: pre-caching of stored functions
wasn't performed for prepared statements just because implementation
of prepared statements is done as an add-on to the main execution flow, 
and the preload was originally implemented for main execution branch
only (mysql_execute_command).

mysql-test/r/ps.result

@@ -456,3 +456,8 @@ PREPARE stmt FROM 'UPDATE t1 AS P1 INNER JOIN (SELECT N FROM t1 GROUP BY N HAVIN
 EXECUTE stmt;
 DEALLOCATE PREPARE stmt;
 DROP TABLE t1;
+create table t1 (a varchar(20));
+insert into t1 values ('foo');
+prepare stmt FROM 'SELECT char_length (a) FROM t1';
+ERROR 42000: FUNCTION test.char_length does not exist
+drop table t1;

mysql-test/t/ps.test

@@ -462,3 +462,14 @@ EXECUTE stmt;
 DEALLOCATE PREPARE stmt;
 DROP TABLE t1;
 
+#
+# Bug#6102 "Server crash with prepared statement and blank after
+# function name"
+# ensure that stored functions are cached when preparing a statement
+# before we open tables
+#
+create table t1 (a varchar(20)); 
+insert into t1 values ('foo'); 
+--error 1305
+prepare stmt FROM 'SELECT char_length (a) FROM t1'; 
+drop table t1;

sql/sql_prepare.cc

@@ -72,6 +72,7 @@ Long data handling:
 #include "sql_select.h" // for JOIN
 #include <m_ctype.h>  // for isspace()
 #include "sp_head.h"
+#include "sp.h"
 #ifdef EMBEDDED_LIBRARY
 /* include MYSQL_BIND headers */
 #include <mysql.h>
@@ -1409,6 +1410,20 @@ static int send_prepare_results(Prepared_statement *stmt, bool text_protocol)
   lex->first_lists_tables_same();
   tables= lex->query_tables;
 
+  /*
+    Preopen 'proc' system table and cache all functions used in this
+    statement. We must do that before we open ordinary tables to avoid
+    deadlocks. We can't open and lock any table once query tables were
+    opened.
+  */
+  if (lex->sql_command != SQLCOM_CREATE_PROCEDURE &&
+      lex->sql_command != SQLCOM_CREATE_SPFUNCTION)
+  {
+    /* the error is print inside */
+    if (sp_cache_functions(thd, lex))
+      DBUG_RETURN(1);
+  }
+
   switch (sql_command) {
   case SQLCOM_REPLACE:
   case SQLCOM_INSERT: