[wpkg-users] removing a package dependency has uninstalled that first package from all clients and then reinstalled

[Paul McGrath]

Hi Rainer,
  It isn't a criticism.  I failed to test the change before deploying so this shouldn't have happened to all my clients anyway.  I under estimated the consequences.
Thanks again
Paul


-----Original Message-----
From: Rainer Meier [mailto:r.meier at wpkg.org] 
Sent: 30 November 2016 22:23
To: Paul McGrath <J.P.McGrath at leeds.ac.uk>; wpkg-users at lists.wpkg.org
Subject: Re: [wpkg-users] removing a package dependency has uninstalled that first package from all clients and then reinstalled

Hi Paul,

On 30.11.2016 23:08, Paul McGrath wrote:
> Hi Rainer,
>   Thank you for the extensive explanation.  I understand all your 
> logic and after consideration I think I did the increment version when 
> removing a dependency before avoiding this problem I had today.  I 
> will document this locally so I don't make the same mistake again.  
> Bit of a pain when 700 computers all try and reinstall SPSS over a few 
> hours :-)

Yes I do understand that this might be annoying and putting load on the clients as well as network and server infrastructure. However my topmost goal when developing WPKG algorithms was to assure that after a synchronization you are in a consistent and fully up-to-date state. And I think the current implementation will asure this on your 700+ machines. Perhaps in this case not in the most efficient way I admit.

In your case it does not matter whether you did increment the VC2008 or .NET package revision when changing the dependencies. The reason is that WPKG will evaluate the dependency tree on client (which includes .NET and VC2008) and on server (which includes only VC2008) and therefore schedules removal in first synchronization step. Thus triggering the removal avalanche.

As the remove happens first there is nothing you can do to prevent this. 
When WPKG starts removing the .NET package it will first make sure there is no package any more which depends on it, actually putting VC2008 and all packages depending on this one to the remove list. During the removal process it will then upgrade VC2008 to latest version, but by this stage it will already have the packages depending on it removed. So there is nothing you can do to prevent this.

I think you pretty much hit the worst case scenario about dependency changes but WPKG will make sure you end up in a consistent state (assuming all your packages uninstall/install properly).

best regards,
Rainer