bk commit into 5.0 tree (evgen:1.2487) BUG#28208

[eugene]

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ChangeSet@stripped, 2007-05-15 23:37:18+04:00, evgen@stripped +3 -0
  Bug#28208: Wrong result of a non-const STRING function with a const DATETIME
  function.
  
  A wrong  condition was used to check that the
  Arg_comparator::can_compare_as_dates() function calculated the value of the
  string constant. When comparing a non-const STRING function with a constant
  DATETIME function it leads to saving an arbitrary value as a cached value of
  the DATETIME function.
  
  Now the Arg_comparator::set_cmp_func() funcion initializes the const_value
  variable to the impossible DATETIME value (-1) and this const_value is
  cached only if it was changed by the Arg_comparator::can_compare_as_dates()
  function.

  mysql-test/r/type_datetime.result@stripped, 2007-05-15 23:36:24+04:00, evgen@stripped
+6 -0
    Added a test case for the bug#28208: Wrong result of a non-const STRING function with
a const DATETIME function.

  mysql-test/t/type_datetime.test@stripped, 2007-05-15 23:36:01+04:00, evgen@stripped +9
-0
    Added a test case for the bug#28208: Wrong result of a non-const STRING function with
a const DATETIME function.

  sql/item_cmpfunc.cc@stripped, 2007-05-15 23:36:51+04:00, evgen@stripped +2 -3
    Bug#28208: Wrong result of a non-const STRING function with a const DATETIME
    function.
    Now the Arg_comparator::set_cmp_func() funcion initializes the const_value
    variable to the impossible DATETIME value (-1) and this const_value is
    cached only if it was changed by the Arg_comparator::can_compare_as_dates()
    function.

# 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:	evgen
# Host:	moonbone.local
# Root:	/mnt/gentoo64/work/28208-bug-5.0-opt-mysql

--- 1.250/sql/item_cmpfunc.cc	2007-05-07 22:22:16.000000000 +0400
+++ 1.251/sql/item_cmpfunc.cc	2007-05-15 23:36:51.000000000 +0400
@@ -661,7 +661,7 @@
                                         Item_result type)
 {
   enum enum_date_cmp_type cmp_type;
-  ulonglong const_value;
+  ulonglong const_value= (ulonglong)-1;
   a= a1;
   b= a2;
 
@@ -674,8 +674,7 @@
     a_cache= 0;
     b_cache= 0;
 
-    if (cmp_type != CMP_DATE_WITH_DATE &&
-        ((*b)->const_item() || (*a)->const_item()))
+    if (const_value != (ulonglong)-1)
     {
       Item_cache_int *cache= new Item_cache_int();
       /* Mark the cache as non-const to prevent re-caching. */

--- 1.42/mysql-test/r/type_datetime.result	2007-05-11 19:56:20.000000000 +0400
+++ 1.43/mysql-test/r/type_datetime.result	2007-05-15 23:36:24.000000000 +0400
@@ -346,3 +346,9 @@
 a	b	a_then_b	b_then_a	c_then_a
 2007-04-10	2007-04-11	2007-04-10	2007-04-10	2004-04-09 00:00:00
 drop procedure test27759;
+create table t1 (f1 date);
+insert into t1 values (curdate());
+select left(f1,10) = curdate() from t1;
+left(f1,10) = curdate()
+1
+drop table t1;

--- 1.28/mysql-test/t/type_datetime.test	2007-05-11 19:56:20.000000000 +0400
+++ 1.29/mysql-test/t/type_datetime.test	2007-05-15 23:36:01.000000000 +0400
@@ -225,3 +225,12 @@
 DELIMITER ;|
 call test27759();
 drop procedure test27759;
+
+#
+# Bug#28208: Wrong result of a non-const STRING function with a const
+#            DATETIME function.
+#
+create table t1 (f1 date);
+insert into t1 values (curdate());
+select left(f1,10) = curdate() from t1;
+drop table t1;