Help debugging package problems

[Bill Moseley <moseley@hank.org>]

I'm running a mix of testing/unstable.

$ cat /etc/apt/apt.conf
APT::Default-Release "testing";
APT::Cache-Limit 10000000;

This is a desktop machine where I want to use new code: I have installed
some packages with apt-get -t unstable install ....

I wonder if that has not caused problems and if I should just move to
unstable.

Is there a good tutorial on debugging package conflicts?  I often try to
install things and apt is refusing to install a package, but I don't
really understand why.  

I'm not looking for only specific answers to why something doens't work,
rather I'd like to learn how to figure out why on my own.

Here's some examples:

# apt-get install locales
Reading Package Lists... Done
Building Dependency Tree... Done
Some packages could not be installed. This may mean that you have
requested an impossible situation or if you are using the unstable
distribution that some required packages have not yet been created
or been moved out of Incoming.

Since you only requested a single operation it is extremely likely that
the package is simply not installable and a bug report against
that package should be filed.
The following information may help to resolve the situation:

Sorry, but the following packages have unmet dependencies:
  locales: Depends: glibc-2.2.5-14.3
E: Sorry, broken packages

Hum, if I go to http://www.debian.org/distrib/packages#search_packages and
type in glibc and select Distribution: any all I see is glibc-doc.

# dpkg -l  libc6
Desired=Unknown/Install/Remove/Purge/Hold
| Status=Not/Installed/Config-files/Unpacked/Failed-config/Half-installed
|/ Err?=(none)/Hold/Reinst-required/X=both-problems (Status,Err:
uppercase=bad)
||/ Name                Version             Description
+++-===================-===================-=================================================
ii  libc6               2.3.1-9             GNU C Library: Shared libraries and Timezone data

Here's another example:

I don't understand why "wine" is to be removed.  I assume there's some
conflict -- can I get apt to me why?

I assume the "kept back" packages are because I've installed those with -t
unstable and I already have a newer version?

# apt-get -s dist-upgrade
Reading Package Lists... Done
Building Dependency Tree... Done
Calculating Upgrade... Done
The following packages will be REMOVED:
  wine 
The following NEW packages will be installed:
  libexif8 libssl0.9.7 
The following packages have been kept back
  jpilot jpilot-plugins libfontconfig1 libfontconfig1-dev libpisock++0
libpisock8 libscrollkeeper0
  pilot-link scrollkeeper sylpheed-claws 
15 packages upgraded, 2 newly installed, 1 to remove and 10  not upgraded.



  
  
  






-- 
Bill Moseley moseley@hank.org