questions about post_change_branch_tip hook

[Alexander Belchenko]

I have some question about post_change_branch_tip:

1) Documentation on 
http://doc.bazaar.canonical.com/test/en/user-reference/hooks-help.html#post-change-branch-tip 
said this hook triggered for push, pull, commit, uncommit. What about 
update command for bound branches? This hook should be invoked for the 
update too, IIUC? Can you reflects this in the help, please?

2) I'm thinking about how to store previous branch tip for pull/update 
operations so I can implement something like whatsnew command to see the 
log (and/or changes) introduced by the last pull.

Question: how can I know in the hook which exactly operation updates the 
tip? ChangeBranchTipParams has no context for this. Should I use 
post_pull hook instead? It seems very old, I hope there is no plans to 
deprecate/remove it?