sources.list

[sotn3m]

Hi all! ;-)
This is going to be my first post here on this forum.
I am quite new to kubuntu, but not necessarily to linux.

I have a question concerning different repositories that are in sources.list. A question raised when I saw on the official kubuntu page that kde 4.1 can be installed by adding new repository to sources.list. I can see that for example, I have qt 4.3 installed right now. New repository have qt 4.4 (again - this is an example).

What would happen (in this example) to qt 4.3 and all of its dependencies? How does apt-get choose which packages it should install? If newer version is to be installed, what happens if the dependencies from the old repository require specifically qt 4.3?
Or maybe apt-get can install both of them so that they can coexist? What should happen when some packages can't coexist?

Thanks for all the answers or links to documentation ;-)

Tomek

[Rog131]

Re: sources.list

What would happen (in this example) to qt 4.3 and all of its dependencies? How does apt-get choose which packages it should install? If newer version is to be installed, what happens if the dependencies from the old repository require specifically qt 4.3?
Or maybe apt-get can install both of them so that they can coexist? What should happen when some packages can't coexist?

> The Debian GNU/Linux FAQ, Chapter 7 - Basics of the Debian package management system
and there:

What is meant by saying that a package Depends, Recommends, Suggests, Conflicts, Replaces or Provides another package?

Links:

> The Debian GNU/Linux FAQ, Chapter 7 - Basics of the Debian package management system
(K/X/Ubuntu is a Debian derived Linux release)

> FAQ: Package Managers

> Repositories

> Repositories (Kubuntu)

> Repositories, backports

> Repositories, PPA

> man sources.list

SOURCES.LIST(5) SOURCES.LIST(5)

NAME
sources.list - Package resource list for APT

DESCRIPTION
The package resource list is used to locate archives of the package
distribution system in use on the system. At this time, this manual
page documents only the packaging system used by the Debian GNU/Linux
system. This control file is located in /etc/apt/sources.list

The source list is designed to support any number of active sources and
a variety of source media. The file lists one source per line, with the
most preferred source listed first. The format of each line is: type
uri args The first item, type determines the format for args uri is a
Universal Resource Identifier (URI), which is a superset of the more
specific and well-known Universal Resource Locator, or URL. The rest of
the line can be marked as a comment by using a #.

Manual (man)

You can get info of commands in the konsole: man <command>

:~$ man man

NAME
man - an interface to the on-line reference manuals

and in the konqueror: man:<command>
man:man will tell:


More > The Art of Using Manuals

[sotn3m]

Re: sources.list

Thanks for the help You have given a bunch of very useful links, but unfortunately I can't see the answer among them.

Manual of apt-get says: 'apt-get has a "smart" conflict resolution system' whatever that means.

Debian FAQ states that 'Package A conflicts with Package B when A will not operate if B is installed on the system. Most often, conflicts are cases where A contains files which are an improvement over those in B. "Conflicts" are often combined with "replaces".'

All in all, I am coming to conclusion that some packages might stop working after an upgrade using additional repository (vide one for kde-4.1), because one package might be working only with the older version of an upgradeable library (qt-4.4 ...). Am I right? (I can't find description of this algorithm)

Tomek

PS I know how man pages work :P

[Fintan]

Re: sources.list

Mabe this will clear things up:

quote from:
http://www.kubuntu.org/news/kde-4.1

Submitted on Tue, 2008-07-29

KDE 4.1 has been released and packages are available for Kubuntu 8.04, the Hardy Heron. These packages install to /usr/lib/kde4 and can be installed along side your existing KDE 3 installation.
Instructions

The updated packages for Kubuntu 8.04 are located in the Kubuntu Member's KDE 4 Personal Package Archive (PPA) repositories. To update to KDE 4.1, please follow these instructions:

1. Add deb http://ppa.launchpad.net/kubuntu-members-kde4/ubuntu hardy main to your /etc/apt/sources.list.
2. If you already have the kubuntu-kde4-desktop packages installed, simply type sudo apt-get update && sudo apt-get dist-upgrade and answer the questions in which you are prompted. If you do not have kubuntu-kde4-desktop installed, simply type sudo apt-get update && sudo apt-get install kubuntu-kde4-desktop and answer the questions. Both of these options are to be typed at the command prompt.

kdeplasma-addons contains new Plasma fun.

Thanks to Harald, Guillaume, Steve, Jon and Arby for preparing these packages.

what this means is simple.

If you have HH 8.04 (kde3 Version) installed kde4.1 will be installed along side and not effect the existing kde3 installation.

If you don't have kde3 and already have kde4.0 (HH 8.04 remmix version) it won't matter because you already have kde4.

You can then choose which session you wish to use at log in.

I hope this clarifies things

[Rog131]

Re: sources.list

All in all, I am coming to conclusion that some packages might stop working after an upgrade using additional repository (vide one for kde-4.1), because one package might be working only with the older version of an upgradeable library (qt-4.4 ...). Am I right?

Googling....

Hmm - there could be problems > VLC + Qt4.4 = crash (QObject::killTimers: timers...)

as a KDE4 svn user I have to use Qt4.4 now and compiled vlc against it. Compilation went (as far as I can see) without problems, but I experience crashes, at least on one computer.
Downgrading Qt4.3 made them go away, so I guess it is a problem with Qt4.4.

With the backports (and ppa repositories) you are taking a small risk that there could be problems (backports):

$release-backports: I have something akin to technology ADHD, needing the latest of everything I can possibly get, but I can’t handle running the development branch.

I think that ppa's are something like the Debian's experimental repositories:

Warning: This package is from the experimental distribution. That means it is likely unstable or buggy, and it may even cause data loss. Please be sure to consult the changelog and other possible documentation before using it.

[sotn3m]

Re: sources.list

No ;> An example:

There is a package python-qt4. It depends on qt 4.3. Let's assume that during kde 4.1 was packaged, python-qt4 was NOT prepared as a package (overlooked) in the PPA repository.
After installation of the kde 4.1, I would probably have only qt 4.4 which would mean that python-qt4 and all packages depending on it should be uninstalled. yes or no?

VLC mentioned by Rog131 is a real example of such a problem - isn't it?

This is something I am thinking about - how is dependency resolved between repositories.
I would like just to know how apt-get and repositories work;-)

Thanks for all the answers!!

Tomek

[Rog131]

Re: sources.list

This is something I am thinking about - how is dependency resolved between repositories.
I would like just to know how apt-get and repositories work ;-)

Hmm - Package manager (apt) just installs the newest version. That is the version that has the biggest version number. If this is not possible = package manager can't resolve the dependencies => error message.


About python-qt4:

depends libqt4-core (>= 4.3.4)

=> Package maintainer thinks/knows that python-qt4 needs at least libqt4-core 4.3.4. So, it should work with the 4.4 or with the 4.5... If it isn't => bug report => fix (hopefully)

And maybe then :
python-qt4:

depends libqt4-core (= 4.3.4)

[sotn3m]

Re: sources.list

This is something I am thinking about - how is dependency resolved between repositories.
I would like just to know how apt-get and repositories work ;-)

Hmm - Package manager (apt) just installs the newest version. That is the version that has the biggest version number. If this is not possible = package manager can't resolve the dependencies => error message.

I though it is smarter

About python-qt4:

depends libqt4-core (>= 4.3.4)

So, it should work with the 4.4 or with the 4.5... If it isn't => bug report => fix (hopefully)

Yes, you are right - I was theorizing what would happen in such a case when it would depend on "=4.3.4"; sorry for not making this clear.

[Rog131]

Re: sources.list

Yes, you are right - I was theorizing what would happen in such a case when it would depend on "=4.3.4";

Then there is depends =4.3.4 => package manager should not install new packages that will break that rule.

Note !
Package installation rules don't guarateen that applications will work on your system. They mean that: "It seems that combination of these packages are working in the test systems" and sometimes they just mean: "They are working in MY system" =>

This is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See theGNU General Public License for more details.

[sotn3m]

Re: sources.list

I like that answer