re-implementing log-for-merge from Arch

[Dan Lipsitt]

What would it take to implement something like the log-for-merge
command present in tla and baz? I found it to be a useful feature. For
those of you not familiar with Bazaar 1 and Arch, it automatically
creates a log message like this, which the user can then edit before
commit:

"""
Summary: Merged from dan at harvard.edu--myarchive (patch 6-7)
Keywords: merge

Patches applied:

 * dan at harvard.edu--myarchive/myproject--mainline--1.1--patch-6
   changes in low-level parallization code

 * dan at harvard.edu--myarchive/myproject--mainline--1.1--patch-7
   new parallelized version
"""

Or is there already a good way to get this info from bzr?

If this is a worthwhile project and it isn't too complicated, I may
try to implement it as a plugin. However, I'm not sure where to begin.

Regards,
Dan