Comment 8 for bug 374735

As long as stacking requires formats to be kept in sync across the base and stacked branch, upgrades will be semi-ugly.

Is it really as simple as 'bzr upgrade URL' for a project trunk that has other branches stacked on it? Will those other branches continue to work? If not, then they must be upgraded as well, right? Until they are, won't they be broken?

If so, then how does one find out what those impacted branches are? LP will need a feature to tell me those branches and who owns them. Owners are potentially anyone on LP, yes? IIUIC, the documented process solves this by simply leaving existing branches alone. So teams can upgrade trunk and just what they want to, when they want to. Isn't that better than putting teams into a situation where things they can't control will become broken?

I appreciate that there are concerns re linked bugs by introducing a fresh trunk. OTOH, listing hundreds of bugs linked to trunk as LP does now is, well, questionable at best from a UI perspective. If this proves a real problem, then LP could gain a feature for moving linked bugs from one branch to another, say.