I'm just filing this to maybe start a discussion.
The use case I'm thinking of is mostly "Make sure my company's custom lint is installed/configured, when I have lots of repos and I don't control the user's setup".
Basically, to offer good support we'd want:
- allow plugins to integrate into arc version and arc upgrade,
- implement arc install-plugin, which will git clone a uri and add it to load in .arcrc
- (nice to have): Have some way for an install to suggest/force a specific plugin/version - maybe in arc diff flow
Then, in my new-user guide, I'd say "Install arc, run arc set-config, arc install-certificate, arc install-plugin".
When arc makes breaking changes, I'd just fix my plugin, and trust the update flow to bring everything together (The same way we do for libphutil and arc repos now).