From: author@example.com
To: commits@list.com
Subject: [cbas] topic branch updated. $new_commit_hash
X-Git-Refname: refs/heads/topic
X-Git-Reftype: branch
X-Git-Oldrev: $old_commit_hash
X-Git-Newrev: $new_commit_hash

The branch, topic has been updated
  discards $old_commit_abbrev update branch with existing commits does not replay them on topic

This update discarded existing revisions and left the branch pointing at
a previous point in the repository history.

 * -- * -- N ($new_commit_hash)
            \
             O -- O -- O ($old_commit_hash)

The removed revisions are not necessarilly gone - if another reference
still refers to them they will stay in the repository.

No new revisions were added by this update.

Summary of changes:
 a |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)