Fix for BUG#9814: Clear thd->net.no_send_error before each SP instruction

execution. Failure to do so caused the erroneous statements to send nothing
and hang the client.

mysql-test/r/sp-error.result

+drop table if exists t1, t2;
 delete from mysql.proc;
 create procedure syntaxerror(t int)|
 ERROR 42000: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '' at line 1
@@ -635,3 +636,32 @@ ERROR 0A000: EXECUTE is not allowed in stored procedures
 create function f() returns int begin execute stmt;
 ERROR 0A000: EXECUTE is not allowed in stored procedures
 deallocate prepare stmt;
+create table t1(f1 int);
+create table t2(f1 int);
+CREATE PROCEDURE SP001()
+P1: BEGIN
+DECLARE ENDTABLE INT DEFAULT 0;
+DECLARE TEMP_NUM INT;
+DECLARE TEMP_SUM INT;
+DECLARE C1 CURSOR FOR SELECT F1 FROM t1;
+DECLARE C2 CURSOR FOR SELECT F1 FROM t2;
+DECLARE CONTINUE HANDLER FOR NOT FOUND SET ENDTABLE = 1;
+SET ENDTABLE=0;
+SET TEMP_SUM=0;
+SET TEMP_NUM=0;
+OPEN C1;
+FETCH C1 INTO TEMP_NUM;
+WHILE ENDTABLE = 0 DO
+SET TEMP_SUM=TEMP_NUM+TEMP_SUM;
+FETCH C1 INTO TEMP_NUM;
+END WHILE;
+SELECT TEMP_SUM;
+CLOSE C1;
+CLOSE C1;
+SELECT 'end of proc';
+END P1|
+call SP001();
+TEMP_SUM
+0
+drop procedure SP001;
+drop table t1, t2;

mysql-test/t/sp-error.test

@@ -2,6 +2,10 @@
 # Stored PROCEDURE error tests
 #
 
+--disable_warnings
+drop table if exists t1, t2;
+--enable_warnings
+
 # Make sure we don't have any procedures left.
 delete from mysql.proc;
 
@@ -933,3 +937,37 @@ create procedure p() execute stmt;
 create function f() returns int begin execute stmt;
 deallocate prepare stmt;
 
+# BUG#9814: Closing a cursor that is not open 
+create table t1(f1 int);
+create table t2(f1 int);
+ 
+delimiter |;
+CREATE PROCEDURE SP001()
+P1: BEGIN
+  DECLARE ENDTABLE INT DEFAULT 0;
+  DECLARE TEMP_NUM INT;
+  DECLARE TEMP_SUM INT;
+  DECLARE C1 CURSOR FOR SELECT F1 FROM t1;
+  DECLARE C2 CURSOR FOR SELECT F1 FROM t2;
+  DECLARE CONTINUE HANDLER FOR NOT FOUND SET ENDTABLE = 1;
+
+  SET ENDTABLE=0;
+  SET TEMP_SUM=0;
+  SET TEMP_NUM=0;
+  
+  OPEN C1;
+
+  FETCH C1 INTO TEMP_NUM;
+  WHILE ENDTABLE = 0 DO
+          SET TEMP_SUM=TEMP_NUM+TEMP_SUM;
+          FETCH C1 INTO TEMP_NUM;
+  END WHILE;
+  SELECT TEMP_SUM;
+  CLOSE C1;
+  CLOSE C1;
+  SELECT 'end of proc';
+END P1|
+delimiter ;|
+call SP001();
+drop procedure SP001;
+drop table t1, t2;

sql/sp_head.cc

@@ -642,6 +642,12 @@ sp_head::execute(THD *thd)
       items made during other permanent subquery transformations).
     */
     thd->current_arena= i;
+    /*
+      no_send_error may have been set by the previous SP instruction when it
+      sent eof. Allow the current SP instruction to produce an error.
+      (multi-statement execution code clears no_send_error, too)
+    */
+    thd->net.no_send_error= 0;
     ret= i->execute(thd, &ip);
     if (i->free_list)
       cleanup_items(i->free_list);