merge result

From: Lynn Lin <lynn.xin.lin@gmail.com>
Date: Sep 9, 2011, 10:54 UTC
Message-ID: <CAPgpnMRrSmVrXD__jxv3uNrek8up+scHp+_Kj8+=HX8tfweWzQ@mail.gmail.com>

Hi All,
   When I merge branch A back to master branch,if there are same
commit(developer do double commit) both in master and A branch, there
will be two same commit in master branch.For example

   1->2->3-4>5        Master
       |
       4->6->7          A

When I merge A branch into master,the two same 4 commit will present in master branch.

Is there any wrong with my operation?

Thanks for your help Lynn