Bug #11964 ALTER TABLE gives wrong error message with sql-mode TRADITIONAL (timestamp)

Description:
ALTER TABLE gives wrong error message with sql-mode TRADITIONAL. This time with a timestamp field.

How to repeat:
[13:28] root@test>CREATE TABLE t1(a int, b timestamp);
Query OK, 0 rows affected (0.01 sec)

5.0.10-beta-debug on 10.17.69.84
[13:28] root@test>ALTER TABLE t1 ADD PRIMARY KEY(a);
ERROR 1067 (42000): Invalid default value for 'b'
5.0.10-beta-debug on 10.17.69.84
[13:29] root@test>

A patch for this bug has been committed. After review, it may
be pushed to the relevant source trees for release in the next
version. You can access the patch from:

  http://lists.mysql.com/internals/27147

A patch for this bug has been committed. After review, it may
be pushed to the relevant source trees for release in the next
version. You can access the patch from:

  http://lists.mysql.com/internals/27547

fixed in 5.0.11

Thank you for your bug report. This issue has been committed to our
source repository of that product and will be incorporated into the
next release.

If necessary, you can access the source repository and build the latest
available version, including the bugfix, yourself. More information 
about accessing the source trees is available at
    http://www.mysql.com/doc/en/Installing_source_tree.html

Additional info:

Documented fix in 5.0.11 changelog.