bk commit into 4.1 tree (cmiller:1.2542) BUG#23411

[Chad MILLER]

Below is the list of changes that have just been committed into a local
4.1 repository of cmiller. When cmiller 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@stripped, 2006-11-06 17:13:19-05:00, cmiller@stripped +4 -0
  Bug#23411: ... MOD-ing zero returns strange result
    
  The Item_func_mod objects never had maybe_null set, so users had no reason 
  to expect that they can be NULL, and may therefore deduce wrong results.
  Now, set maybe_null.

  BitKeeper/etc/collapsed@stripped, 2006-11-06 16:41:39-05:00, cmiller@stripped +1 -0

  BitKeeper/etc/collapsed@stripped, 2006-11-06 15:40:16-05:00, cmiller@stripped +1 -0

  mysql-test/r/func_test.result@stripped, 2006-11-06 17:13:17-05:00,
cmiller@stripped +75 -0
    Verify that the predictions are true.

  mysql-test/t/func_test.test@stripped, 2006-11-06 17:13:17-05:00, cmiller@stripped
+32 -0
    Verify that the predictions are true.

  sql/item_func.cc@stripped, 2006-11-06 17:13:17-05:00, cmiller@stripped +2 -1
    MOD functions may be NULL.

# 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:	cmiller
# Host:	zippy.cornsilk.net
# Root:	/home/cmiller/work/mysql/bug23411/my41-bug23411

--- 1.267/sql/item_func.cc	2006-11-06 17:13:21 -05:00
+++ 1.268/sql/item_func.cc	2006-11-06 17:13:21 -05:00
@@ -96,7 +96,7 @@ Item_func::Item_func(THD *thd, Item_func
 
 
 /*
-  Resolve references to table column for a function and it's argument
+  Resolve references to table column for a function and its argument
 
   SYNOPSIS:
   fix_fields()
@@ -707,6 +707,7 @@ longlong Item_func_mod::val_int()
 void Item_func_mod::fix_length_and_dec()
 {
   Item_num_op::fix_length_and_dec();
+  maybe_null= 1;
 }
 
 

--- 1.1/BitKeeper/etc/collapsed	2006-11-06 17:13:21 -05:00
+++ 1.3/BitKeeper/etc/collapsed	2006-11-06 17:13:21 -05:00
@@ -1 +1,3 @@
 452a92d0-31-8wSzSfZi165fcGcXPA
+454a7ef8gdvE_ddMlJyghvOAkKPNOQ
+454f8960jsVT_kMKJtZ9OCgXoba0xQ

--- 1.28/mysql-test/r/func_test.result	2006-11-06 17:13:21 -05:00
+++ 1.29/mysql-test/r/func_test.result	2006-11-06 17:13:21 -05:00
@@ -183,3 +183,78 @@ select 5.1 mod 3, 5.1 mod -3, -5.1 mod 3
 select 5 mod 3, 5 mod -3, -5 mod 3, -5 mod -3;
 5 mod 3	5 mod -3	-5 mod 3	-5 mod -3
 2	2	-2	-2
+select (12%0) <=> null      as '1';
+1
+1
+select (12%0) is null       as '1';
+1
+1
+select 12%0                 as 'NULL';
+NULL
+NULL
+select 12%2                 as '0';
+0
+0
+select 12%NULL              as 'NULL';
+NULL
+NULL
+select 12 % null            as 'NULL';
+NULL
+NULL
+select null % 12            as 'NULL';
+NULL
+NULL
+select null % 0             as 'NULL';
+NULL
+NULL
+select 0 % null             as 'NULL';
+NULL
+NULL
+select null % null          as 'NULL';
+NULL
+NULL
+select (12 mod 0) <=> null  as '1';
+1
+1
+select (12 mod 0) is null   as '1';
+1
+1
+select 12 mod 0             as 'NULL';
+NULL
+NULL
+select 12 mod 2             as '0';
+0
+0
+select 12 mod null          as 'NULL';
+NULL
+NULL
+select null mod 12          as 'NULL';
+NULL
+NULL
+select null mod 0           as 'NULL';
+NULL
+NULL
+select 0 mod null           as 'NULL';
+NULL
+NULL
+select null mod null        as 'NULL';
+NULL
+NULL
+select mod(12.0, 0)         as 'NULL';
+NULL
+NULL
+select mod(12, 0.0)         as 'NULL';
+NULL
+NULL
+select mod(12, NULL)        as 'NULL';
+NULL
+NULL
+select mod(12.0, NULL)      as 'NULL';
+NULL
+NULL
+select mod(NULL, 2)         as 'NULL';
+NULL
+NULL
+select mod(NULL, 2.0)       as 'NULL';
+NULL
+NULL

--- 1.26/mysql-test/t/func_test.test	2006-11-06 17:13:21 -05:00
+++ 1.27/mysql-test/t/func_test.test	2006-11-06 17:13:21 -05:00
@@ -108,4 +108,36 @@ select 5.1 mod 3, 5.1 mod -3, -5.1 mod 3
 
 select 5 mod 3, 5 mod -3, -5 mod 3, -5 mod -3;
 
+#
+# Bug#23411: The "%" (MOD) operator is not documented; MOD-ing zero returns strange
result
+# Manual: "Division by zero produces a NULL result"
+#
+select (12%0) <=> null      as '1';
+select (12%0) is null       as '1';
+select 12%0                 as 'NULL';
+select 12%2                 as '0';
+select 12%NULL              as 'NULL';
+select 12 % null            as 'NULL';
+select null % 12            as 'NULL';
+select null % 0             as 'NULL';
+select 0 % null             as 'NULL';
+select null % null          as 'NULL';
+
+select (12 mod 0) <=> null  as '1';
+select (12 mod 0) is null   as '1';
+select 12 mod 0             as 'NULL';
+select 12 mod 2             as '0';
+select 12 mod null          as 'NULL';
+select null mod 12          as 'NULL';
+select null mod 0           as 'NULL';
+select 0 mod null           as 'NULL';
+select null mod null        as 'NULL';
+
+select mod(12.0, 0)         as 'NULL';
+select mod(12, 0.0)         as 'NULL';
+select mod(12, NULL)        as 'NULL';
+select mod(12.0, NULL)      as 'NULL';
+select mod(NULL, 2)         as 'NULL';
+select mod(NULL, 2.0)       as 'NULL';
+
 # End of 4.1 tests