World file cleaner tool?

Dragonlord · Guru Joined: 22 Aug 2004 Posts: 446 Location: Switzerland

I've had yet another blocker problem for which in the end I went through the world file and tried to delete nilly-willy stuff in the hope to get it working.

Now when I understand this correctly then the world file should only contain stuff I installed "manually". It seems at times dependency stuff gets in there or manual stuff turns dependency. So looking at this problem I'm curious to know if there is a tool which you can run over the world file to identify entries which are dependencies of other packages and thus should not be in the world file (anymore).

Does such a tool exist or could the gentoo devs add such a tool? (or the functionality to another tool that exists already)
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charles17 · Advocate Joined: 02 Mar 2008 Posts: 3664

See https://wiki.gentoo.org/wiki/World_set_%28Portage%29#Keep_it_clean

saboya · Guru Joined: 28 Nov 2006 Posts: 552 Location: Brazil

No, because there's no way to make sure it SHOULD'T be in the world file. A lot of assumptions could be made, such as "libs are probably not what you want there", but in some cases you might actually do that for a reason.

You just have to be careful when emerging stuff. emerge it with -1 if you don't want it added to the world file.

The Doctor · Moderator Joined: 27 Jul 2010 Posts: 2678

As Saboya said, writing such a tool is impossible in principle. When you write software you may add libs for your project, for example.

Fortunately there is an easy way to clean the file, but be warned that it may break things if you are careless. Move the /var/lib/portage/world file to a safe backup location. Do NOT edit the file! Run emerge -pc Note the -p!

emerge --noreplace <foo> <bar> every user selected package that appears and you want to keep. For example, emerge --noreplace kde-meta but not kactivitymanager or plasma-desktop

Do it in small bites and leave out everything you are unsure of until latter. The end of the process should be a list of packages that you don't want or don't recognize. These will probably be mostly libraries. Let depclean take care of those. Run emerge -auvND world just to be perfectly safe.
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Dragonlord · Guru Joined: 22 Aug 2004 Posts: 446 Location: Switzerland

That sounds horribly complicated and error prone to say the least. Furthermore it's anything else but user friendly. The logic I had in mind is a lot simpler. I don't see why this logic doesn't work.
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ct85711 · Veteran Joined: 27 Sep 2005 Posts: 1791

The reason that this logic doesn't work, is how do you tell if some library is something you want or not? For all purposes, there is no way for the computer to if something in the world file is something you need/want. The most the computer can do is determine if something is a dependency of something else or not. Take for example, plasma-meta or gnome-base/gnome; 2 meta packages that provides everything, but often isn't a dependency. How is a computer (with no user input) is suppose to know it is needed. It will it is not needed, and remove them; which will cause everything else to get removed. This is why, there is no way for a program to do this, as it has no way telling.

Jaglover · Posted: Sun Sep 10, 2017 3:49 am Post subject:

My tool has been vim, just deleted everything that does not belong there. Over the years I got into habit to use -1 with emerge, so my world file stays clean. I see no danger editing it manually.
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saboya · Guru Joined: 28 Nov 2006 Posts: 552 Location: Brazil

What I can recommend is that it's a lot easier to manage sets. Usually you emerge something for a purpose, so you can create "purpose sets" and add apps to the set and just emerge -uavDN @world.

I have @dev, @media, @gui, @games, @gcc6, @basic-apps-gui, stuff like that. So I just emerge @media and I know all my media-related packages are there, and whenever something related to that changes, I remove/add them to the set and just emerge -uavDN @world / emerge --depclean.

(Actually I usually add them to the set and emerge -1 <PACKAGE> since it's faster, but you get the idea).

The Doctor · Moderator Joined: 27 Jul 2010 Posts: 2678

The Doctor · Moderator Joined: 27 Jul 2010 Posts: 2678

Actually, the problem with the proposed world cleaner utility is that if you have libfoo-2.4 in your world file and libfoo-3.5 installed it may not identify libfoo-2.4 as extra since nothing depends on it anymore. Worse, libbar was added to world but orphaned so nothing depends on it either. These orphaned libraries are usually what cause problems and are impossible to detect using a tool.

The get rid of world and rebuild it approach is actually very easy to use since it is self critiquing. It takes maybe a half hour, tops.
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First things first, but not necessarily in that order.

Apologies if I take a while to respond. I'm currently working on the dematerialization circuit for my blue box.

Jaglover · Posted: Sun Sep 10, 2017 5:36 am Post subject:

Dragonlord · Guru Joined: 22 Aug 2004 Posts: 446 Location: Switzerland

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