From: Date: June 6 2006 7:36pm
Subject: bk commit into 4.1 tree (bar:1.2487) BUG#11728
List-Archive: http://lists.mysql.com/commits/7331
X-Bug: 11728
Message-Id: <200606061736.k56HatpO004007@bar.intranet.mysql.r18.ru>

Below is the list of changes that have just been committed into a local
4.1 repository of bar. When bar does a push these changes will
be propagated to the main repository and, within 24 hours after the
push, to the public repository.
For information on how to access the public repository
see http://dev.mysql.com/doc/mysql/en/installing-source-tree.html

ChangeSet
  1.2487 06/06/06 22:36:49 bar@stripped +3 -0
  Bug#11728 string function LEFT, strange undocumented behaviour, strict mode
  Problem: LEFT and RIGHT returnd empty string if the second argument was NULL.
  Fix: return NULL if any argument is NULL

  sql/item_strfunc.cc
    1.242 06/06/06 22:36:44 bar@stripped +2 -2
    Return NULL if either of arguments is NULL

  mysql-test/t/func_str.test
    1.82 06/06/06 22:36:44 bar@stripped +5 -0
    Adding test case

  mysql-test/r/func_str.result
    1.100 06/06/06 22:36:44 bar@stripped +3 -0
    Adding test case

# This is a BitKeeper patch.  What follows are the unified diffs for the
# set of deltas contained in the patch.  The rest of the patch, the part
# that BitKeeper cares about, is below these diffs.
# User:	bar
# Host:	bar.intranet.mysql.r18.ru
# Root:	/usr/home/bar/mysql-4.1.b11228

--- 1.241/sql/item_strfunc.cc	2006-05-08 06:39:19 +05:00
+++ 1.242/sql/item_strfunc.cc	2006-06-06 22:36:44 +05:00
@@ -978,7 +978,7 @@ String *Item_func_left::val_str(String *
   long length  =(long) args[1]->val_int();
   uint char_pos;
 
-  if ((null_value=args[0]->null_value))
+  if ((null_value=(args[0]->null_value || args[1]->null_value)))
     return 0;
   if (length <= 0)
     return &my_empty_string;
@@ -1018,7 +1018,7 @@ String *Item_func_right::val_str(String 
   String *res  =args[0]->val_str(str);
   long length  =(long) args[1]->val_int();
 
-  if ((null_value=args[0]->null_value))
+  if ((null_value=(args[0]->null_value || args[1]->null_value)))
     return 0; /* purecov: inspected */
   if (length <= 0)
     return &my_empty_string; /* purecov: inspected */

--- 1.99/mysql-test/r/func_str.result	2006-05-08 06:38:08 +05:00
+++ 1.100/mysql-test/r/func_str.result	2006-06-06 22:36:44 +05:00
@@ -33,6 +33,9 @@ position(binary 'll' in 'hello')	positio
 select left('hello',2),right('hello',2),substring('hello',2,2),mid('hello',1,5) ;
 left('hello',2)	right('hello',2)	substring('hello',2,2)	mid('hello',1,5)
 he	lo	el	hello
+select left('hello',null), right('hello',null);
+left('hello',null)	right('hello',null)
+NULL	NULL
 select concat('',left(right(concat('what ',concat('is ','happening')),9),4),'',substring('monty',5,1)) ;
 concat('',left(right(concat('what ',concat('is ','happening')),9),4),'',substring('monty',5,1))
 happy

--- 1.81/mysql-test/t/func_str.test	2006-05-08 06:37:13 +05:00
+++ 1.82/mysql-test/t/func_str.test	2006-06-06 22:36:44 +05:00
@@ -19,6 +19,11 @@ select locate('he','hello'),locate('he',
 select instr('hello','HE'), instr('hello',binary 'HE'), instr(binary 'hello','HE'); 
 select position(binary 'll' in 'hello'),position('a' in binary 'hello');
 select left('hello',2),right('hello',2),substring('hello',2,2),mid('hello',1,5) ;
+#
+# Bug#11728 string function LEFT,
+# strange undocumented behaviour, strict mode
+#
+select left('hello',null), right('hello',null);
 select concat('',left(right(concat('what ',concat('is ','happening')),9),4),'',substring('monty',5,1)) ;
 select substring_index('www.tcx.se','.',-2),substring_index('www.tcx.se','.',1);
 select substring_index('www.tcx.se','tcx',1),substring_index('www.tcx.se','tcx',-1);