Review of new code since last pull

- Use %lx instead of %p as %p is not portable
- Don't replace ROW item with Item_null


myisam/mi_rkey.c:
  Use %lx instead of %p as %p is not portable
myisam/mi_search.c:
  Use %lx instead of %p as %p is not portable
mysql-test/r/select.result:
  More test for ROW comparison
mysql-test/t/select.test:
  More test for ROW comparison
sql/item.cc:
  We can't replace a ROW item with Item_null because:
  - Arg_comparator is still using the orignal row items and it's not good to have args[0] different from what is actually compared
  - If we are using the <=> comparator, NULL can still be compared as true
  - We would break things if we would ever use resolve_const_item() for operators like >, < etc.

myisam/mi_rkey.c

@@ -31,8 +31,8 @@ int mi_rkey(MI_INFO *info, byte *buf, int inx, const byte *key, uint key_len,
   HA_KEYSEG *last_used_keyseg;
   uint pack_key_length, use_key_length, nextflag;
   DBUG_ENTER("mi_rkey");
-  DBUG_PRINT("enter", ("base: %p  buf: %p  inx: %d  search_flag: %d",
-                       info, buf, inx, search_flag));
+  DBUG_PRINT("enter", ("base: %lx  buf: %lx  inx: %d  search_flag: %d",
+                       (long) info, (long) buf, inx, search_flag));
 
   if ((inx = _mi_check_index(info,inx)) < 0)
     DBUG_RETURN(my_errno);

myisam/mi_search.c

@@ -257,15 +257,16 @@ int _mi_seq_search(MI_INFO *info, register MI_KEYDEF *keyinfo, uchar *page,
     if (length == 0 || page > end)
     {
       my_errno=HA_ERR_CRASHED;
-      DBUG_PRINT("error",("Found wrong key:  length: %u  page: %p  end: %p",
-                          length, page, end));
+      DBUG_PRINT("error",("Found wrong key:  length: %u  page: %lx  end: %lx",
+                          length, (long) page, (long) end));
       DBUG_RETURN(MI_FOUND_WRONG_KEY);
     }
     if ((flag=ha_key_cmp(keyinfo->seg,t_buff,key,key_len,comp_flag,
                           &not_used)) >= 0)
       break;
 #ifdef EXTRA_DEBUG
-    DBUG_PRINT("loop",("page: %p  key: '%s'  flag: %d", page, t_buff, flag));
+    DBUG_PRINT("loop",("page: %lx  key: '%s'  flag: %d", (long) page, t_buff,
+                       flag));
 #endif
     memcpy(buff,t_buff,length);
     *ret_pos=page;
@@ -273,7 +274,7 @@ int _mi_seq_search(MI_INFO *info, register MI_KEYDEF *keyinfo, uchar *page,
   if (flag == 0)
     memcpy(buff,t_buff,length);                 /* Result is first key */
   *last_key= page == end;
-  DBUG_PRINT("exit",("flag: %d  ret_pos: %p", flag, *ret_pos));
+  DBUG_PRINT("exit",("flag: %d  ret_pos: %lx", flag, (long) *ret_pos));
   DBUG_RETURN(flag);
 } /* _mi_seq_search */
 
@@ -412,8 +413,8 @@ int _mi_prefix_search(MI_INFO *info, register MI_KEYDEF *keyinfo, uchar *page,
     if (page > end)
     {
       my_errno=HA_ERR_CRASHED;
-      DBUG_PRINT("error",("Found wrong key:  length: %u  page: %p  end: %p",
-                          length, page, end));
+      DBUG_PRINT("error",("Found wrong key:  length: %u  page: %lx  end: %lx",
+                          length, (long) page, (long) end));
       DBUG_RETURN(MI_FOUND_WRONG_KEY);
     }
 
@@ -546,7 +547,7 @@ int _mi_prefix_search(MI_INFO *info, register MI_KEYDEF *keyinfo, uchar *page,
 
   *last_key= page == end;
 
-  DBUG_PRINT("exit",("flag: %d  ret_pos: %p", flag, *ret_pos));
+  DBUG_PRINT("exit",("flag: %d  ret_pos: %lx", flag, (long) *ret_pos));
   DBUG_RETURN(flag);
 } /* _mi_prefix_search */
 
@@ -807,8 +808,8 @@ uint _mi_get_pack_key(register MI_KEYDEF *keyinfo, uint nod_flag,
 	  if (length > keyseg->length)
 	  {
 	    DBUG_PRINT("error",
-                       ("Found too long null packed key: %u of %u at %p",
-                        length, keyseg->length, *page_pos));
+                       ("Found too long null packed key: %u of %u at %lx",
+                        length, keyseg->length, (long) *page_pos));
 	    DBUG_DUMP("key",(char*) *page_pos,16);
 	    my_errno=HA_ERR_CRASHED;
 	    return 0;
@@ -863,8 +864,8 @@ uint _mi_get_pack_key(register MI_KEYDEF *keyinfo, uint nod_flag,
       }
       if (length > (uint) keyseg->length)
       {
-        DBUG_PRINT("error",("Found too long packed key: %u of %u at %p",
-                            length, keyseg->length, *page_pos));
+        DBUG_PRINT("error",("Found too long packed key: %u of %u at %lx",
+                            length, keyseg->length, (long) *page_pos));
         DBUG_DUMP("key",(char*) *page_pos,16);
         my_errno=HA_ERR_CRASHED;
         return 0;                               /* Error */
@@ -928,8 +929,8 @@ uint _mi_get_binary_pack_key(register MI_KEYDEF *keyinfo, uint nod_flag,
   {
     if (length > keyinfo->maxlength)
     {
-      DBUG_PRINT("error",("Found too long binary packed key: %u of %u at %p",
-                          length, keyinfo->maxlength, *page_pos));
+      DBUG_PRINT("error",("Found too long binary packed key: %u of %u at %lx",
+                          length, keyinfo->maxlength, (long) *page_pos));
       DBUG_DUMP("key",(char*) *page_pos,16);
       my_errno=HA_ERR_CRASHED;
       DBUG_RETURN(0);                                 /* Wrong key */
@@ -975,8 +976,8 @@ uint _mi_get_binary_pack_key(register MI_KEYDEF *keyinfo, uint nod_flag,
       length-=tmp;
       from=page; from_end=page_end;
     }
-    DBUG_PRINT("info",("key: %p  from: %p  length: %u",
-		       key, from, length));
+    DBUG_PRINT("info",("key: %lx  from: %lx  length: %u",
+		       (long) key, (long) from, length));
     memcpy_overlap((byte*) key, (byte*) from, (size_t) length);
     key+=length;
     from+=length;
@@ -1031,7 +1032,8 @@ uchar *_mi_get_key(MI_INFO *info, MI_KEYDEF *keyinfo, uchar *page,
       }
     }
   }
-  DBUG_PRINT("exit",("page: %p  length: %u", page, *return_key_length));
+  DBUG_PRINT("exit",("page: %lx  length: %u", (long) page,
+                     *return_key_length));
   DBUG_RETURN(page);
 } /* _mi_get_key */
 
@@ -1082,7 +1084,7 @@ uchar *_mi_get_last_key(MI_INFO *info, MI_KEYDEF *keyinfo, uchar *page,
   uint nod_flag;
   uchar *lastpos;
   DBUG_ENTER("_mi_get_last_key");
-  DBUG_PRINT("enter",("page: %p  endpos:  %p", page, endpos));
+  DBUG_PRINT("enter",("page: %lx  endpos: %lx", (long) page, (long) endpos));
 
   nod_flag=mi_test_if_nod(page);
   if (! (keyinfo->flag & (HA_VAR_LENGTH_KEY | HA_BINARY_PACK_KEY)))
@@ -1102,13 +1104,15 @@ uchar *_mi_get_last_key(MI_INFO *info, MI_KEYDEF *keyinfo, uchar *page,
       *return_key_length=(*keyinfo->get_key)(keyinfo,nod_flag,&page,lastkey);
       if (*return_key_length == 0)
       {
-        DBUG_PRINT("error",("Couldn't find last key:  page: %p", page));
+        DBUG_PRINT("error",("Couldn't find last key:  page: %lx",
+                            (long) page));
         my_errno=HA_ERR_CRASHED;
         DBUG_RETURN(0);
       }
     }
   }
-  DBUG_PRINT("exit",("lastpos: %p  length: %u", lastpos, *return_key_length));
+  DBUG_PRINT("exit",("lastpos: %lx  length: %u", (long) lastpos,
+                     *return_key_length));
   DBUG_RETURN(lastpos);
 } /* _mi_get_last_key */
 
@@ -1644,7 +1648,8 @@ _mi_calc_var_pack_key_length(MI_KEYDEF *keyinfo,uint nod_flag,uchar *next_key,
         ref_length=0;
         next_length_pack=0;
      }
-      DBUG_PRINT("test",("length: %d  next_key: %p", length, next_key));
+      DBUG_PRINT("test",("length: %d  next_key: %lx", length,
+                         (long) next_key));
 
       {
         uint tmp_length;

mysql-test/r/select.result

@@ -2625,4 +2625,11 @@ select f1 from t1,t2 where f1=f2 and (f1,NULL) = ((1,1));
 f1
 select f1 from t1,t2 where f1=f2 and (f1,f2) = ((1,NULL));
 f1
+insert into t1 values(1,1),(2,null);
+insert into t2 values(2);
+select * from t1,t2 where f1=f3 and (f1,f2) = (2,null);
+f1	f2	f3
+select * from t1,t2 where f1=f3 and (f1,f2) <=> (2,null);
+f1	f2	f3
+2	NULL	2
 drop table t1,t2;

mysql-test/t/select.test

@@ -2172,6 +2172,10 @@ create table t2(f3 int);
 select f1 from t1,t2 where f1=f2 and (f1,f2) = ((1,1));
 select f1 from t1,t2 where f1=f2 and (f1,NULL) = ((1,1));
 select f1 from t1,t2 where f1=f2 and (f1,f2) = ((1,NULL));
+insert into t1 values(1,1),(2,null);
+insert into t2 values(2);
+select * from t1,t2 where f1=f3 and (f1,f2) = (2,null);
+select * from t1,t2 where f1=f3 and (f1,f2) <=> (2,null);
 drop table t1,t2; 
 
 # End of 4.1 tests

sql/item.cc

@@ -2872,32 +2872,21 @@ void resolve_const_item(THD *thd, Item **ref, Item *comp_item)
   }
   else if (res_type == ROW_RESULT)
   {
+    Item_row *item_row= (Item_row*) item;
+    Item_row *comp_item_row= (Item_row*) comp_item;
+    uint col;
     new_item= 0;
     /*
       If item and comp_item are both Item_rows and have same number of cols
-      then process items in Item_row one by one. If Item_row contain nulls
-      substitute it by Item_null. Otherwise just return.
+      then process items in Item_row one by one.
+      We can't ignore NULL values here as this item may be used with <=>, in
+      which case NULL's are significant.
     */
-    if (item->result_type() == comp_item->result_type() &&
-        ((Item_row*)item)->cols() == ((Item_row*)comp_item)->cols())
-    {
-      Item_row *item_row= (Item_row*)item,*comp_item_row= (Item_row*)comp_item;
-      if (item_row->null_inside())
-        new_item= (Item*) new Item_null(name);
-      else
-      {
-        int i= item_row->cols() - 1;
-        for (; i >= 0; i--)
-        {
-          if (item_row->maybe_null && item_row->el(i)->is_null())
-          {
-            new_item= (Item*) new Item_null(name);
-            break;
-          }
-          resolve_const_item(thd, item_row->addr(i), comp_item_row->el(i));
-        }
-      }
-    }
+    DBUG_ASSERT(item->result_type() == comp_item->result_type());
+    DBUG_ASSERT(item_row->cols() == comp_item_row->cols());
+    col= item_row->cols();
+    while (col-- > 0)
+      resolve_const_item(thd, item_row->addr(col), comp_item_row->el(col));
   }
   else
   {						// It must REAL_RESULT