landing brisbane-core Q: development5/6 vs gc-chk-* plan?

[Ian Clatworthy]

Being an "experimental" branch, brisbane-core has a bunch
of new potential formats. Are we planning to roll those into
bzr.dev and only expose one externally? Or should we pick
one and remove the code supporting the others?

In particular, lots of the new tests explicitly state the
repo format as "development5" or "development5-subtree".
Should those change to development6, particularly as the
WT version needs to rev to wt6 (now that filtered views are
excluded from wt5)?

In the brisbane-core branch, try something like:

  bzr cdiff -rancestor:../bzr.dev bzrlib/tests/test_pack_repository.py | less -r

for an example of code that could be simplified by going
with just one gc format in bzr.dev.

Thoughts?

Ian C.