From: Petter Reinholdtsen Date: Tue, 27 Jul 2010 21:47:06 +0000 (+0000) Subject: Ny post. X-Git-Url: https://pere.pagekite.me/gitweb/homepage.git/commitdiff_plain/22c9c0cf1c59768d55d9a326663219baa81ed499?ds=inline Ny post. --- diff --git a/blog/data/2010-07-27-circdeps.txt b/blog/data/2010-07-27-circdeps.txt new file mode 100644 index 0000000000..b084ced1af --- /dev/null +++ b/blog/data/2010-07-27-circdeps.txt @@ -0,0 +1,52 @@ +Title: Circular package dependencies harms apt recovery +Tags: english, nuug, debian +Date: 2010-07-27 23:50 + +

I discovered this while doing +automated +testing of upgrades from Debian Lenny to Squeeze. A few packages +in Debian still got circular dependencies, and it is often claimed +that apt and aptitude should be able to handle this just fine, but +some times these dependency loops causes apt to fail.

+ +

An example is from todays +upgrade +of KDE using aptitude. In it, a bug in kdebase-workspace-data +causes perl-modules to fail to upgrade. The cause is simple. If a +package fail to unpack, then only part of packages with the circular +dependency might end up being unpacked when unpacking aborts, and the +ones already unpacked will fail to configure in the recovery phase +because its dependencies are unavailable.

+ +

In this log, the problem manifest itself with this error:

+ +
+dpkg: dependency problems prevent configuration of perl-modules:
+ perl-modules depends on perl (>= 5.10.1-1); however:
+  Version of perl on system is 5.10.0-19lenny2.
+dpkg: error processing perl-modules (--configure):
+ dependency problems - leaving unconfigured
+
+ +

The perl/perl-modules circular dependency is already +reported as a bug, and will +hopefully be solved as soon as possible, but it is not the only one, +and each one of these loops in the dependency tree can cause similar +failures. Of course, they only occur when there are bugs in other +packages causing the unpacking to fail, but it is rather nasty when +the failure of one package causes the problem to become worse because +of dependency loops.

+ +

Thanks to +the +tireless effort by Bill Allombert, the number of circular +dependencies +left in Debian +is dropping, and perhaps it will reach zero one day. :)

+ +

Todays testing also exposed a bug in +update-notifier and +different behaviour between +apt-get and aptitude, the latter possibly caused by some circular +dependency. Reported both to BTS to try to get someone to look at +it.