1 files changed, 17 insertions, 14 deletions

diff --git a/sql/sp_head.cc b/sql/sp_head.cc
index 3c610c1fdf0..0287ed8f2c2 100644
--- a/sql/sp_head.cc
+++ b/sql/sp_head.cc
@@ -336,16 +336,18 @@ bool
 sp_eval_expr(THD *thd, Field *result_field, Item **expr_item_ptr)
 {
   Item *expr_item;
+  enum_check_fields save_count_cuted_fields= thd->count_cuted_fields;
+  bool save_abort_on_warning= thd->abort_on_warning;
+  bool save_stmt_modified_non_trans_table= 
+    thd->transaction.stmt.modified_non_trans_table;
 
   DBUG_ENTER("sp_eval_expr");
 
   if (!*expr_item_ptr)
-    DBUG_RETURN(TRUE);
+    goto error;
 
   if (!(expr_item= sp_prepare_func_item(thd, expr_item_ptr)))
-    DBUG_RETURN(TRUE);
-
-  bool err_status= FALSE;
+    goto error;
 
   /*
     Set THD flags to emit warnings/errors in case of overflow/type errors
@@ -354,10 +356,6 @@ sp_eval_expr(THD *thd, Field *result_field, Item **expr_item_ptr)
     Save original values and restore them after save.
   */
   
-  enum_check_fields save_count_cuted_fields= thd->count_cuted_fields;
-  bool save_abort_on_warning= thd->abort_on_warning;
-  bool save_stmt_modified_non_trans_table= thd->transaction.stmt.modified_non_trans_table;
-
   thd->count_cuted_fields= CHECK_FIELD_ERROR_FOR_NULL;
   thd->abort_on_warning=
     thd->variables.sql_mode &
@@ -372,13 +370,18 @@ sp_eval_expr(THD *thd, Field *result_field, Item **expr_item_ptr)
   thd->abort_on_warning= save_abort_on_warning;
   thd->transaction.stmt.modified_non_trans_table= save_stmt_modified_non_trans_table;
 
-  if (thd->is_error())
-  {
-    /* Return error status if something went wrong. */
-    err_status= TRUE;
-  }
+  if (!thd->is_error())
+    DBUG_RETURN(FALSE);
 
-  DBUG_RETURN(err_status);
+error:
+  /*
+    In case of error during evaluation, leave the result field set to NULL.
+    Sic: we can't do it in the beginning of the function because the 
+    result field might be needed for its own re-evaluation, e.g. case of 
+    set x = x + 1;
+  */
+  result_field->set_null();
+  DBUG_RETURN (TRUE);
 }