specify charm to upgrade to

[William Reade]

It would be nice to make upgrade-charm a little more sophisticated: at the moment, all it will do is upgrade to the latest version in the repository. A --revision option would probably be relatively painless to add, and would allow for simple charm downgrades where necessary; alternatively, a --charm option that allowed us to switch to *any* other (compatible) charm would enable some interesting behaviour (eg cross(?)grade from cs:precise/blah-123 to local:precise/blah-101, which is derived from the original but contains my own, urgent, local, changes).

Opinions?

See also lp:1032557

[William Reade (fwereade)]

(see also lp:1040210)

[Dimiter Naydenov (dimitern)]

This is now implemented in the linked branch pending for review: --switch to pick charm URL to upgrade to, and --revision to specify a revision (rather than the latest) explicitly. Those two flags cannot be combined.