bk commit into 4.1 tree (bar:1.2487) BUG#11728

[bar]

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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);