Add a way for germinate-update-metapackage to recursively add packages from seeds specified in the "Task-Seeds:" field

[Alexandros Frantzis]

Binary package hint: germinate

germinate-update-metapackage only uses packages from seeds explicitly specified in a seeds "Task-Seeds:" field. This makes it hard to create and maintain seeds that have a long inheritance chain. It would be desirable to have germinate-update-metapackage add packages recursively from the seeds specified in "Task-Seeds:", perhaps using some special notation.

For example in linaro, one portion of the seed hierarchy is:

minimal (from plaform) -> linaro-headless -> linaro-x11-base -> linaro-xfce-base -> linaro-alip

(eg other parts are ... linaro-x11-base -> linaro-netbook-efl ... linaro-xfce-base -> linaro-xfce)

In this case linaro-alip wants to include all packages from all seeds in the hierarchy below it.

For things to work correctly right now, the linaro-alip seed has to have "Task-Seeds: linaro-xfce-base linaro-x11-base linaro-headless minimal", which means that linaro-alip has to know about the whole hierarchy explicitly. This makes it hard to maintain the seeds.

If there was a way to mark a seed as "recursively-added" then linaro-alip could just depend on a "recursively-added" linaro-xfce-base eg "Task-Seeds: *linaro-xfce-base"

[Colin Watson (cjwatson)]

Acknowledged; but I wonder why you don't just use intermediate metapackages. This wasn't supposed to be an issue because I didn't envision that people would be attempting to use Task-Seeds all the way down the inheritance chain. For Ubuntu, an example looks like this:

  required → minimal → standard → desktop-common → desktop

minimal declares Task-Seeds: required, and desktop declares Task-Seeds: desktop-common; we don't need to do more than that because there exist ubuntu-minimal, ubuntu-standard, and ubuntu-desktop metapackages. Task-Seeds was only meant to bridge the gap between seeds where it's worth building metapackages for them.