Re: Moving existing ostree users to a new branch - take 2

[Alexander Larsson <alexl redhat com>]

On Wed, 2017-05-03 at 12:53 -0400, Matthias Clasen wrote:
> On Wed, 2017-05-03 at 09:49 -0600, Daniel Drake wrote:
>
> > I'd be interested in any comments on the new design here, before we
> > start the full code review process.
>
> I'm not sure if this has been brought up before, but we are also
> interested in being able to forward between different repositories. I
> don't think that can work if the only information about this is
> stored
> in the summary for the new branch, since the clients won't know about
> the new repository that this summary resides in...

In fact, i'm currently looking into doing this, and the design will
probably be quite similar. i.e. some metadata in the summary file, that
if set will rewrite the configuration of the remote.

However, I don't think modifying the repo configuration in the middle
of a pull operation like this patch does it is right. For instance,
flatpak has a much more complex use of repos to do "pull as user then
install systemwide using polkit". Changing the config where we pull is
a no-op as we essentially throw that away, and changing the system one
needs more complex operation.

In the case of forwarding the entire remote there is further complexity
in that you need to re-download the summary if the URL changed. Also,
the branch name changing affects a lot of extra things in flatpak,
since this changes the application id, and these are things that ostree
doesn't know about.

So, instead of hiding this in the pull operation we will do this in a
separate step that flatpak runs before it tries to install/update
something. I think something similar is probably better for ostree
admin update too.

-- 
=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
 Alexander Larsson                                            Red Hat, Inc 
       alexl redhat com            alexander larsson gmail com 
He's a shy vegetarian boxer with a winning smile and a way with the 
ladies. She's a time-travelling African-American magician's assistant 
from out of town. They fight crime!