The following points were raised during https://code.launchpad.net/~vila/bzr/deprecation-warning-preference/+merge/16233
- the actual implementation use a single global variable for the whole code base,
forget about being warned for the second repo accessed (or the 20th for bzrlib users),
that should be implemented as a repo attribute instead,
- working trees can raise format deprecation warnings too, they should use the new
facility (I don't think we want to proliferate warning variables gratuitously)
- hpss remote repositories don't raise the warning locally (AFAICS but feel free
to prove me wrong),
- no distinction is made between read and write access (I'm not sure I understand
the need here),
- there is no config file for repositories were such an option can be specified.
Since bzr more or less always winds up making VFS requests when using the hpss, you still get the warning when that happens. Whether that was intended, I don't know.