bk commit into 4.1 tree (igor:1.2129)

[igor]

Below is the list of changes that have just been committed into a local
4.1 repository of igor. When igor 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
  1.2129 05/01/15 01:05:00 igor@stripped +3 -0
  func_gconcat.result, func_gconcat.test:
    Added a test case for bug #7769.
  item_sum.h:
    Fixed bug #7769: a crash for queries with group_concat and
    having when the query table was empty.
    The bug was due an unsafe dereferencing.

  mysql-test/r/func_gconcat.result
    1.33 05/01/15 01:04:32 igor@stripped +5 -0
    Added a test case for bug #7769.

  mysql-test/t/func_gconcat.test
    1.24 05/01/15 01:04:11 igor@stripped +7 -0
    Added a test case for bug #7769.

  sql/item_sum.h
    1.77 05/01/15 01:01:29 igor@stripped +3 -2
    Fixed bug #7769: a crash for queries with group_concat and
    having when the query table was empty.
    The bug was due an unsafe dereferencing.

# 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:	igor
# Host:	rurik.mysql.com
# Root:	/home/igor/dev/mysql-4.1-0

--- 1.76/sql/item_sum.h	Tue Dec  7 11:18:12 2004
+++ 1.77/sql/item_sum.h	Sat Jan 15 01:01:29 2005
@@ -739,9 +739,10 @@
     String *res;
     char *end_ptr;
     int error;
-    res= val_str(&str_value);
+    if (!(res= val_str(&str_value)))
+      return (longlong) 0;
     end_ptr= (char*) res->ptr()+ res->length();
-    return res ? my_strtoll10(res->ptr(), &end_ptr, &error) : (longlong) 0;
+    return my_strtoll10(res->ptr(), &end_ptr, &error);
   }
   String* val_str(String* str);
   Item *copy_or_same(THD* thd);

--- 1.32/mysql-test/r/func_gconcat.result	Sun Oct 10 00:10:44 2004
+++ 1.33/mysql-test/r/func_gconcat.result	Sat Jan 15 01:04:32 2005
@@ -457,3 +457,8 @@
 Warnings:
 Warning	1260	2 line(s) were cut by GROUP_CONCAT()
 drop table t1;
+CREATE TABLE t1 (id int);
+SELECT GROUP_CONCAT(id) AS gc FROM t1 HAVING gc IS NULL;
+gc
+NULL
+DROP TABLE t1;

--- 1.23/mysql-test/t/func_gconcat.test	Sun Oct 10 00:10:44 2004
+++ 1.24/mysql-test/t/func_gconcat.test	Sat Jan 15 01:04:11 2005
@@ -277,3 +277,10 @@
 select group_concat(distinct b order by b) from t1 group by a;
 
 drop table t1;
+
+#
+# bug #7769: group_concat returning null is checked in having
+#
+CREATE TABLE t1 (id int);
+SELECT GROUP_CONCAT(id) AS gc FROM t1 HAVING gc IS NULL;
+DROP TABLE t1;