bk commit into 5.0 tree (gkodinov:1.2253)

[kgeorge]

Below is the list of changes that have just been committed into a local
5.0 repository of kgeorge. When kgeorge does a push these changes will
be propagated to the main repository and, within 24 hours after the
push, to the public repository.
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ChangeSet@stripped, 2006-08-14 18:48:27+03:00, gkodinov@rakia.(none) +1 -0
  Merge gkodinov@stripped:/home/bk/mysql-5.0-opt
  into  rakia.(none):/home/kgeorge/mysql/autopush/B21159-5.0-opt
  MERGE: 1.2226.5.1

  sql/sql_select.cc@stripped, 2006-08-14 18:48:23+03:00, gkodinov@rakia.(none) +0 -0
    Auto merged
    MERGE: 1.439.1.1

# 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:	gkodinov
# Host:	rakia.(none)
# Root:	/home/kgeorge/mysql/autopush/B21159-5.0-opt/RESYNC

--- 1.440/sql/sql_select.cc	2006-08-14 18:48:33 +03:00
+++ 1.441/sql/sql_select.cc	2006-08-14 18:48:33 +03:00
@@ -6499,8 +6499,23 @@ static bool check_equality(Item *item, C
         field_item= (Item_field*) right_item;
         const_item= left_item;
       }
+      /* 
+        Disable const propagation for Item_hex_string.
+        This must be done because Item_hex_string->val_int() is not
+        the same as (Item_hex_string->val_str() in BINARY column)->val_int().
+        We cannot simply disable the replacement in a particular context (
+        e.g. <bin_col> = <int_col> AND <bin_col> = <hex_string>) since
+        Items don't know the context they are in and there are functions like 
+        IF (<hex_string>, 'yes', 'no').
+        Note that this will disable some valid cases as well 
+        (e.g. : <bin_col> = <hex_string> AND <bin_col2> = <bin_col>) but 
+        there's no way to distinguish the valid cases without having the
+        Item's parent say something like : Item->set_context(Item::STRING_RESULT)
+        and have all the Items that contain other Items do that consistently.
+      */
       if (const_item &&
-          field_item->result_type() == const_item->result_type())
+          field_item->result_type() == const_item->result_type() &&
+          const_item->type() != Item::VARBIN_ITEM)
       {
         bool copyfl;