Blag

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A Glimpse Into cave: Mask and Use Flag Overriding for Resolves

For a long time, Paludis has been able to work out suggestions for what unmaskings you might want to do when installing a particular package that is either masked or has masked dependencies. This functionality is also present in the shiny new cave client, which uses the much more powerful new resolver. Now this functionality is also available for unmet use dependencies.

For example, rather than getting pages and pages of errors when attempting to install gnome:

resolve gnome errors with no overrides

You’ll now get:

resolve gnome errors

Note how you are told all the suggested changes up-front. You aren’t just given a single error, which you can fix and then re-run the command to get another error and so on. Nor are you just given all the errors in the initial resolution; the resolver carries on with its suggested changes and accumulates any additional errors that will occur if you take those suggestions. In the first example, parted isn’t mentioned at all in the initial set of errors, because it is only brought in to the resolution by udisks, which is only brought in via gnome-disk-utility, which is only brought in via gvfs if the gdu use flag is enabled, which we don’t have enabled by our config but that is required by gnome. The resolver is smart enough to work all of this out upfront, sparing you from an eternity of running things over and over.

We’re still experimenting with the UI for errors — it’s probably possible to make it even easier for the user to see what changes need to be made. There have also been requests to make cave able to add the necessary lines to your configuration files automatically (after confirmation, of course). However, I’m not convinced that this is a good idea in practice — for example, cave would suggest turning a particular use flag on for a half dozen packages, but would not realise that turning it on globally may be a better option.

As always, if you find that all these shiny new features save you from horrible torment, books or pens (pens being a vital part of the high tech design process) are much appreciated.

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4 responses to “A Glimpse Into cave: Mask and Use Flag Overriding for Resolves

  1. JL August 9, 2010 at 6:00 pm

    Any chance that you’ll add that for blockers as well?

    • Ciaran McCreesh August 9, 2010 at 6:07 pm

      You can do –remove-if-dependent to remove blocked packages. It’s not tried by default because unlike Portage, we don’t like uninstalling bash without the user’s permission…

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