'bzr branch --stacked' silently upgrades source, fails, and breaks 'bzr branch'?

[Matt Nordhoff]

I have two or three issues here...

OK, so I'm running bzr.dev, and I have a rich-root-pack branch at
<http://bzr.mattnordhoff.com/bzr/imports/lighttpd/trunk/> (note:
bzr+http is enabled on that branch).

A while ago (several days or a week or two?), I logged into the server
and ran "bzr branch --stacked /srv/bzr/imports/lighttpd/trunk/" twice.
Both times, it failed with this error:

IncompatibleRepositories: Repository
KnitPackRepository('file:///srv/bzr/imports/lighttpd/.bzr/repository/')
is not compatible with repository
KnitPackRepository('file:///tmp/lighttpd-trunk2/.bzr/repository/')

An hour ago, I tried to run "bzr branch
http://bzr.mattnordhoff.com/bzr/imports/lighttpd/trunk/", outside of any
sort of shared repo, and it failed with this:

IncompatibleRepositories:
KnitPackRepository('file:///tmp/trunk/.bzr/repository/')
is not compatible with
RemoteRepository(http://bzr.mattnordhoff.com/bzr/imports/lighttpd/.bzr/)
different rich-root support

Um, what? Why didn't it create the new repo as rich-root-pack?!

If I create a new rich-root-pack shared repo and then try to branch into
it, it works fine.

It also works fine even if I'm not in a shared repo if I try to branch
over nosmart+http.

Anyway, now onto my last issue: While investigating this, I ran "bzr
info -v" on the source branch, and the shared repo is rich-root-pack,
but the branch is "Branch format 7"! When did that happen? Why was it
upgraded, and why wasn't I told? Also, how the heck do I downgrade it?

...

OK, here's an important update, but I'm tired of dealing with this and
don't feel like editing my message:

I just used the init/pull trick to downgrade back to branch6. (As an
aside, I really hate that hack. It is not an excuse for "bzr upgrade"
being unable to support dropping features like rich roots or stacking.)
If you want to work with this, the branch 7 version of the branch is now
located at
<http://bzr.mattnordhoff.com/bzr/imports/lighttpd/.trunk.branch7/>.
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