Gentoo Archives: gentoo-devhelp

From: Nikos Chantziaras <realnc@×××××.de>
To: gentoo-devhelp@l.g.o
Subject: [gentoo-devhelp] Re: Writing ebuilds that replace others but with different name
Date: Thu, 24 Sep 2009 21:00:59
Message-Id: h9gmla$ml4$
In Reply to: Re: [gentoo-devhelp] Writing ebuilds that replace others but with different name by Justin
On 09/24/2009 11:38 PM, Justin wrote:
> Nikos Chantziaras wrote: >> I seem to have some fundamental "flaw" in portage. It seems I am not >> able to write an ebuild that will in effect be able to replace another >> one but with a different name. >> >> With RPMs, no matter how the RPM is named, it has "provides" data in it. >> Is there some similar mechanism in portage? It seems to me that if the >> name of an ebuild is changed, then *all* ebuilds depending on it will >> have to change too. That looks like a PITA to me if it's true. >> >> For example, if I have an overlay that provides alternative/altered >> packages of already existing ones in the portage tree, they will "clash" >> with portage. Let's assume that my overlay provides an ebuild called >> "foo-alt" which is a variation of a package in portage called "foo", but >> is totally compatible with it. What I'm looking for is being able to >> emerge "foo-alt", but have the ebuild state clearly that it provides the >> "foo" dependency, so ebuilds depending on "foo" will be satisfied if >> "foo-alt" is installed but "foo" isn't. >> >> Possible? >> >> > Thats's what virtuals are good for. As an example see virtual/jre. > But in principle you are right. renaming a package is a headache and > should really be avoided.
I'm not sure how I can use virtuals to provide an alternative but completely compatible package. I'll give a straight example: In my overlay, there's "x11-libs/qt-opengl-alt". It is a variation of qt-opengl, providing and *replacing* all files in it. However, if I unmerge qt-opengl and install qt-opengl-alt instead, even though the installed packages depending on qt-opengl work perfectly fine with it (it's fully compatible), an "emerge -uDN world" will try to pull qt-opengl back in because it thinks it's missing (and this will of course result in a file collision since qt-opengl-alt is also installed, providing the same files). Changing the category also doesn't help ("x11-libs-alt/qt-opengl" for example). So virtuals don't seem to have anything to do with with my problem. What's missing is something like RPM's "provides" (so the qt-opengl-alt ebuild would be able to say "I provide the qt-opengl package.) From your answer, I take it that portage doesn't offer anything like this and the ebuild's name is hardcoded to be the package it provides :P


Subject Author
Re: [gentoo-devhelp] Re: Writing ebuilds that replace others but with different name Justin <justin@×××××××××.net>