Merge ahristov@bk-internal.mysql.com:/home/bk/mysql-5.1-wl3337

into  example.com:/work/mysql-5.1-runtime-wl3337

sql/sql_lex.cc

@@ -175,6 +175,7 @@ void lex_start(THD *thd, const uchar *buf, uint length)
   lex->proc_list.first= 0;
   lex->escape_used= FALSE;
   lex->reset_query_tables_list(FALSE);
+  lex->expr_allows_subselect= TRUE;
 
   lex->name= 0;
   lex->event_parse_data= NULL;

sql/sql_lex.h

@@ -958,6 +958,14 @@ typedef struct st_lex : public Query_tables_list
   */
   nesting_map allow_sum_func;
   enum_sql_command sql_command;
+  /*
+    Usually `expr` rule of yacc is quite reused but some commands better
+    not support subqueries which comes standard with this rule, like
+    KILL, HA_READ, CREATE/ALTER EVENT etc. Set this to `false` to get
+    syntax error back.
+  */
+  bool expr_allows_subselect;
+
   thr_lock_type lock_option;
   enum SSL_type ssl_type;			/* defined in violite.h */
   enum my_lex_states next_state;

sql/sql_yacc.yy

@@ -1302,8 +1302,9 @@ event_tail:
             $<ulong_num>$= YYTHD->client_capabilities & CLIENT_MULTI_QUERIES;
             YYTHD->client_capabilities &= (~CLIENT_MULTI_QUERIES);
 
-            /* We need that for disallowing subqueries */
             Lex->sql_command= SQLCOM_CREATE_EVENT;
+            /* We need that for disallowing subqueries */
+            Lex->expr_allows_subselect= FALSE;
           }
           ON SCHEDULE_SYM ev_schedule_time
           opt_ev_on_completion
@@ -1325,6 +1326,7 @@ event_tail:
               can overwrite it
             */
             Lex->sql_command= SQLCOM_CREATE_EVENT;
+            Lex->expr_allows_subselect= TRUE;
           }
 
 
@@ -4697,8 +4699,9 @@ alter:
             $<ulong_num>$= YYTHD->client_capabilities & CLIENT_MULTI_QUERIES;
             YYTHD->client_capabilities &= ~CLIENT_MULTI_QUERIES;
 
-            /* we need that for disallowing subqueries */
             Lex->sql_command= SQLCOM_ALTER_EVENT;
+            /* we need that for disallowing subqueries */
+            Lex->expr_allows_subselect= FALSE;
           }
           ev_alter_on_schedule_completion
           opt_ev_rename_to
@@ -4724,6 +4727,7 @@ alter:
               can overwrite it
             */
             Lex->sql_command= SQLCOM_ALTER_EVENT;
+            Lex->expr_allows_subselect= TRUE;
           }
         | ALTER TABLESPACE alter_tablespace_info
           {
@@ -7048,10 +7052,7 @@ select_derived2:
         {
 	  LEX *lex= Lex;
 	  lex->derived_tables|= DERIVED_SUBQUERY;
-          if (lex->sql_command == SQLCOM_HA_READ ||
-              lex->sql_command == SQLCOM_KILL ||
-              lex->sql_command == SQLCOM_CREATE_EVENT ||
-              lex->sql_command == SQLCOM_ALTER_EVENT)
+          if (!lex->expr_allows_subselect)
 	  {
 	    yyerror(ER(ER_SYNTAX_ERROR));
 	    YYABORT;
@@ -8554,11 +8555,17 @@ purge_option:
 /* kill threads */
 
 kill:
-	KILL_SYM { Lex->sql_command= SQLCOM_KILL; } kill_option expr
+	KILL_SYM
+        {
+          Lex->sql_command= SQLCOM_KILL;
+          Lex->expr_allows_subselect= FALSE;
+        }
+        kill_option expr
 	{
 	  LEX *lex=Lex;
 	  lex->value_list.empty();
 	  lex->value_list.push_front($4);
+          Lex->expr_allows_subselect= TRUE;
 	};
 
 kill_option:
@@ -10038,6 +10045,7 @@ handler:
 	    my_error(ER_SP_BADSTATEMENT, MYF(0), "HANDLER");
 	    YYABORT;
 	  }
+          lex->expr_allows_subselect= FALSE;
 	  lex->sql_command = SQLCOM_HA_READ;
 	  lex->ha_rkey_mode= HA_READ_KEY_EXACT;	/* Avoid purify warnings */
 	  lex->current_select->select_limit= new Item_int((int32) 1);
@@ -10045,7 +10053,10 @@ handler:
 	  if (!lex->current_select->add_table_to_list(lex->thd, $2, 0, 0))
 	    YYABORT;
         }
-        handler_read_or_scan where_clause opt_limit_clause {}
+        handler_read_or_scan where_clause opt_limit_clause
+        {
+          Lex->expr_allows_subselect= TRUE;
+        }
         ;
 
 handler_read_or_scan:
@@ -10670,10 +10681,7 @@ subselect_start:
 	'(' SELECT_SYM
 	{
 	  LEX *lex=Lex;
-          if (lex->sql_command == SQLCOM_HA_READ ||
-              lex->sql_command == SQLCOM_KILL ||
-              lex->sql_command == SQLCOM_CREATE_EVENT ||
-              lex->sql_command == SQLCOM_ALTER_EVENT)
+          if (!lex->expr_allows_subselect)
 	  {
             yyerror(ER(ER_SYNTAX_ERROR));
 	    YYABORT;