No, I'm proposing this only for installers, and that only as halfway
measure for all those relatively simple packages that you can't install
only for lacking the proper service.

This is definitely NOT a proposed replacement to having configuration
package types that encapsulate things like dependencies (though the idea
of a reflective service that uses SM itself might be useful in other
contexts too).

I personally don't think we should model dependencies directly. If
Goran's view of configurations is "I assert that the RB 1.2 works with
PackageInfo 3.4", then my proposal is the agnostic "Loading PackageInfo
3.4 and then RB 1.2 and then ... is good". 

This could obviously be used to make sure both dependencies and proper
scaffolding is installed before any specific package.

This handles any depth dependencies in one configuration, and also
allows composition of configurations to make packaging modular.

Does this seem reasonable?

Daniel

Julian Fitzell <julian at beta4.com> wrote:
> Daniel,
> 
> Are you suggesting this only for installers or for all dependencies? 
> I'd hate to have to manually install the dependencies for a package. 
> You might easily have a few levels of depth in your dependencies.
> 
> Julian
> 
> Daniel Vainsencher wrote:
> > I think I see what you mean. Let's see if I do:
> > There's a conflict between expecting the services architecture to
> > provide you with the correct installer for each package automatically,
> > and between using any external dependency mechanism to represent this
> > dependency.
> > 
> > I think a good enough solution is - 
> > 1. The services architecture will not cause installation of anything,
> > but it will help expose any packages to all services already installed
> > in the image.
> > 2. One of those services might use SqueakMap categories to find
> > appropriate installers, and offer that option (example later).
> > 
> > Example:
> > I want to install the RB package. It has the category PackageType\SAR.
> > All the SM services I have installed come forth and decide that they
> > cannot install SARs, because none of them is SARInstaller. However, one
> > of them is the Meta Installer (tm), and it detects that there's a
> > package in SM that has the category PackageService\Installer\SAR (which
> > happens to be called SARInstaller), and so offers to "install
> > SARInstaller" on the menu. After the user chooses that, he now has
> > SARInstaller, and will be able to install the RB.
> > 
> > This takes care of the light weight scenario, where it should be
> > straight forward for the user to install simple single packages, and
> > would solve our current problem. 
> > 
> > Another scenario is the image configuration scenario, and I see nothing
> > wrong in it loading first some installers, and then the needed packages.
> > 
> > Daniel Vainsencher
> > 
> > 
> > goran.hultgren at bluefish.se wrote:
> > 
> >>Julian Fitzell <julian at beta4.com> wrote:
> >>
> >>>goran.hultgren at bluefish.se wrote:
> >>>
> >>>>Julian Fitzell <julian at beta4.com> wrote:
> >>>>[SNIP]
> >>>>
> >>>>
> >>>>>I didn't say SqueakMap depended on SARInstaller.  I meant that packages 
> >>>>>that are packaged as SARs depend on SARInstaller.  So when you try to 
> >>>>>install a SAR package and don't have SARInstaller, it will get installed 
> >>>>>first since it is a dependency.
> >>>>
> >>>>
> >>>>Duh. Ok, sorry - didn't read careful enough. Yes, this would be neat.
> >>>>But... hmmm. Interesting. It wouldn't work at all with the current
> >>>>architecture - nor the one I am aiming for in 1.1. Hmmmm.
> >>>
> >>>I'm curious why it doesn't work with what you're planning.  Isn't it 
> >>>just a simple matter of giving the package a dependency on the 
> >>>installer?  Presumably all the dependencies are installed prior to the 
> >>>package itsself?
> >>>
> >>>I'm guessing I'm missing something obvious.
> >>
> >>Well, there are two issues at play here:
> >>
> >>1. The service architecture for finding the "actions" that you can do
> >>with a package. Today each subclass of SMInstaller is queried if it
> >>would like to handle package x and the first one that says yes gets to
> >>supply "download" and/or "install". So if you don't have the installer
> >>already installed - how does it raise its hand and say "Yes, I can
> >>handle this package!". The future architecture that I have started
> >>fiddling with collects services from registered "package handler
> >>objects" instead - the services can be anything and there may be
> >>services from multiple handlers. Anyway, the problem is still the same.
> >>
> >>2. When thinking more this is actually not a normal dependency. In the
> >>planned SM 1.1+ people will register "package configurations" with the
> >>dependencies for *using* package x. Not the dependencies for
> >>*installing* it. I think these two things are different - for example -
> >>the installer can easily be uninstalled after it has done its work - a
> >>"normal" dependency can't be.
> >>
> >>So, what do we do? Well, after thinking about 20 seconds I am not sure I
> >>would like to use "normal" dependencies for this. And it does feel like
> >>overkill to introduce some other dependency structure just to handle
> >>installation. I think perhaps we should be a bit more strict when it
> >>comes to "Package type" - perhaps making it mandatory. And given this we
> >>could perhaps map to at least a default installer package. I am not
> >>sure..
> >>
> >>I need to get a new revision of SM out - if you have any bright ideas
> >>regarding the above I am listening.
> >>
> >>regards, Gsran
> > 
> > 
> 
> 
> -- 
> julian at beta4.com
> Beta4 Productions (http://www.beta4.com)