Is this right?

[David Ingamells]

Vincent Ladeuil wrote:
>>>>>> "Russel" == Russel Winder <russel.winder at concertant.com> writes:
>>>>>>             
>
>     Russel> Guillermo,
>     Russel> On Mon, 2008-11-03 at 20:00 -0200, Guillermo Gonzalez wrote:
>     >> Hi,
>     >> 
>     >> On Mon, Nov 3, 2008 at 7:45 PM, Aaron Bentley <aaron at aaronbentley.com> wrote:
>     >> > -----BEGIN PGP SIGNED MESSAGE-----
>     >> > Hash: SHA1
>     >> >
>     >> > Russel Winder wrote:
>     >> >> Uuurrr... this used to work fine and now....
>     >> >>
>     >> >>
>     >> >> Using saved parent location: bzr
>     >> >> +ssh://russel@bazaar.launchpad.net/~guillo.gonzo/bzr-xmloutput/trunk/
>     >> >> bzr: ERROR: Not a branch: "bzr
>     >> >> +ssh://russel@bazaar.launchpad.net/~guillo.gonzo/bzr-xmloutput/trunk/".
>     >> >
>     >> > Apparently Guillermo Gonzalez has changed his shortname from
>     >> > guillo.gonzo to verterok, which would break old urls.
>     >> 
>     >> Indeed,  Apolgize the inconvenience.
>
>     Russel> Well this will certainly screw up
>
> 'screw' seems a bit excessive here, the branch is not updated so
> it's as good as it was before the pull (merge, missing ?).
>
>     Russel> everyone using a branch of this branch
>
> And this is good. That branch has ceased to exist. You got a copy
> the last time you pulled from it, that's the best you can hope in
> a distributed world.
>
> We can blame Guillermo, but what if, instead of changing his
> name, he created another lp user ?
>
> You get no notice that the branch you're pointing to is now a
> dead one and will forever stay subscribed.
>
> And what if you're subscribed to a branch that must be relocated
> on another site because (put any reason here) ?
>
> For any change outside of your control, you have to act.
>
>     Russel> since there appears to have been no announcement
>     Russel> anywhere of the change.
>
> I don't think announcements are a way to solve that *kind* of
> problem. 
>
> In that specific case it could have helped you, yes, but in
> general there is no link between a branch and its subscribers, so
> there is now way to warn all the subscribers.
>
>     >> Rusell, running: bzr pull --remember lp:bzr-xmloutput  should fix it.
>
>     Russel> It does appear to have done.  But remember everyone
>     Russel> has the bzr+ssh: protocol URL stored so another
>     Russel> change will cause people further aggravation.
>
> We could blame the way 'lp:' protocol works here as it chases the
> pointer and gives back
> bzr+ssh://bazaar.launchpad.net/%7Everterok/bzr-xmloutput/trunk/
> which indeed is another failure waiting to happen.
>
> Or we could blame verterok for not putting his branch under
> bzr+ssh://bazaar.launchpad.net/~bzr-xmloutpu/bzr-xmloutput/trunk/
> which should remain valid longer.
>
> But in the end, branch URLs just change, that's a fact of life.
>
>     Russel> I think failing to announce this sort of change
>
> Even if we had the list of the branches based on this branch,
> what can be done ? Part of these are obviously not reachable,
> some may have cease to exist, that list should also include a way
> to contact the branch owner, what about anonymous owners ?
>
> Etc, etc.
>
>     Russel> and assuming that everyone will divine that it has
>     Russel> happened 
>
> You got a BzrNotABranch error, which is the best bzr can do
> without a crystal ball (it can't divine either).
>
>     Russel> and will know exactly what to do, is not a way of
>     Russel> progressing.
>
> In that specific case, you can argue that lp could redirect the
> old ID branches to the new ones (but that means keeping the old
> ID in use) and in that case, depending on how lp implement it,
> bzr may even warn you that a redirection has occurred... but
> that's really a tiny fraction of a branch death possible causes.
>
>     Russel> I should note that this is not the first time...
>
> And certainly not the last. I could also mention having been
> instructed to subscribe to a branch which was not updated as
> regularly as the one I really wanted...
>
>     Russel> Apologies for being grumpy on this 
>
> This is understandable, I went into it a couple of times too.
>
>     Russel> but it is these small things that get to be
>     Russel> the most irritating.
>
> This is certainly not a small thing but a social or
> organizational problem, nothing bzr can address other than
> providing the easiest way to take the change into account when
> the new url is provided. And this is exactly what --remember
> does.
>
> But if you have any idea on how to handle the general problem
> better, I'm surely interested.
>
>         Vincent
>
> P.S.: Nice bug summary shape here
> https://bugs.launchpad.net/bzr-xmloutput :-)
>
>   
I think I might have asked this before, but can't remember seeing a reply.

It looks to me that the only way to update the parent reference is to do 
an action that might update the contents of your local branch (e.g. bzr 
pull --remember). Therefore the --remember is just a side-effect of 
another command.

Is there a way to redirect to a new parent location that is the main and 
/only/ action on the local branch (apart from any sanity checks that the 
redirect is a sensible thing to do)?

Thanks, David.