Fix for BUG#13037: undefined variable in IF cause erroneous error-message.

mysql-test/r/sp-error.result:
  Results for the test case for BUG#13037.
mysql-test/t/sp-error.test:
  Test case for BUG#13037.
sql/sql_base.cc:
  Polishing: use constant.
sql/sql_class.cc:
  Reset THD::where in THD::cleanup_after_query();
  Polishing: use the constant (THD::DEFAULT_WHERE).
sql/sql_class.h:
  Introduce a constant for the default value of THD::where.

mysql-test/r/sp-error.result

@@ -444,9 +444,9 @@ set b = a;
 end if;
 end|
 call bug2653_1(1, @b)|
-ERROR 42S22: Unknown column 'aa' in 'order clause'
+ERROR 42S22: Unknown column 'aa' in 'field list'
 call bug2653_2(2, @b)|
-ERROR 42S22: Unknown column 'aa' in 'order clause'
+ERROR 42S22: Unknown column 'aa' in 'field list'
 drop procedure bug2653_1|
 drop procedure bug2653_2|
 create procedure bug4344() drop procedure bug4344|
@@ -883,3 +883,36 @@ select count(*) into param1 from t3;
 end|
 ERROR 3D000: No database selected
 use test;
+DROP PROCEDURE IF EXISTS bug13037_p1;
+DROP PROCEDURE IF EXISTS bug13037_p2;
+DROP PROCEDURE IF EXISTS bug13037_p3;
+CREATE PROCEDURE bug13037_p1()
+BEGIN
+IF bug13037_foo THEN
+SELECT 1;
+END IF;
+END|
+CREATE PROCEDURE bug13037_p2()
+BEGIN
+SET @bug13037_foo = bug13037_bar;
+END|
+CREATE PROCEDURE bug13037_p3()
+BEGIN
+SELECT bug13037_foo;
+END|
+
+CALL bug13037_p1();
+ERROR 42S22: Unknown column 'bug13037_foo' in 'field list'
+CALL bug13037_p2();
+ERROR 42S22: Unknown column 'bug13037_bar' in 'field list'
+CALL bug13037_p3();
+ERROR 42S22: Unknown column 'bug13037_foo' in 'field list'
+CALL bug13037_p1();
+ERROR 42S22: Unknown column 'bug13037_foo' in 'field list'
+CALL bug13037_p2();
+ERROR 42S22: Unknown column 'bug13037_bar' in 'field list'
+CALL bug13037_p3();
+ERROR 42S22: Unknown column 'bug13037_foo' in 'field list'
+DROP PROCEDURE bug13037_p1;
+DROP PROCEDURE bug13037_p2;
+DROP PROCEDURE bug13037_p3;

mysql-test/t/sp-error.test

@@ -1284,6 +1284,60 @@ begin
 end|
 delimiter ;|
 use test;
+
+
+#
+# BUG#13037: undefined variable in IF cause erroneous error-message
+#
+
+--disable_warnings
+DROP PROCEDURE IF EXISTS bug13037_p1;
+DROP PROCEDURE IF EXISTS bug13037_p2;
+DROP PROCEDURE IF EXISTS bug13037_p3;
+--enable_warnings
+
+delimiter |;
+
+CREATE PROCEDURE bug13037_p1()
+BEGIN
+  IF bug13037_foo THEN
+    SELECT 1;
+  END IF;
+END|
+
+CREATE PROCEDURE bug13037_p2()
+BEGIN
+  SET @bug13037_foo = bug13037_bar;
+END|
+
+CREATE PROCEDURE bug13037_p3()
+BEGIN
+  SELECT bug13037_foo;
+END|
+
+delimiter ;|
+
+--echo
+
+--error 1054
+CALL bug13037_p1();
+--error 1054
+CALL bug13037_p2();
+--error 1054
+CALL bug13037_p3();
+
+--error 1054
+CALL bug13037_p1();
+--error 1054
+CALL bug13037_p2();
+--error 1054
+CALL bug13037_p3();
+
+DROP PROCEDURE bug13037_p1;
+DROP PROCEDURE bug13037_p2;
+DROP PROCEDURE bug13037_p3;
+
+
 # BUG#NNNN: New bug synopsis
 #
 #--disable_warnings

sql/sql_base.cc

@@ -4272,7 +4272,7 @@ bool setup_fields(THD *thd, Item **ref_pointer_array,
 
   thd->set_query_id=set_query_id;
   thd->allow_sum_func= allow_sum_func;
-  thd->where="field list";
+  thd->where= THD::DEFAULT_WHERE;
 
   /*
     To prevent fail on forward lookup we fill it with zerows,

sql/sql_class.cc

@@ -44,6 +44,8 @@
 */
 char internal_table_name[2]= "*";
 
+const char * const THD::DEFAULT_WHERE= "field list";
+
 
 /*****************************************************************************
 ** Instansiate templates
@@ -234,7 +236,7 @@ THD::THD()
 
   /* Variables with default values */
   proc_info="login";
-  where="field list";
+  where= THD::DEFAULT_WHERE;
   server_id = ::server_id;
   slave_net = 0;
   command=COM_CONNECT;
@@ -545,6 +547,8 @@ void THD::cleanup_after_query()
   }
   /* Free Items that were created during this execution */
   free_items();
+  /* Reset where. */
+  where= THD::DEFAULT_WHERE;
 }
 
 /*

sql/sql_class.h

@@ -1109,6 +1109,14 @@ class THD :public Statement,
            public Open_tables_state
 {
 public:
+  /*
+    Constant for THD::where initialization in the beginning of every query.
+
+    It's needed because we do not save/restore THD::where normally during
+    primary (non subselect) query execution.
+  */
+  static const char * const DEFAULT_WHERE;
+
 #ifdef EMBEDDED_LIBRARY
   struct st_mysql  *mysql;
   struct st_mysql_data *data;