[mythtv-users] Debian 'apt-get build-dep mythtv' problem?

[kteague@speakeasy.net]

> -----Original Message-----
> From: A JM [mailto:vbtalent at gmail.com]
> Sent: Friday, January 27, 2006 08:03 PM
> To: 'Discussion about mythtv'
> Subject: Re: [mythtv-users] Debian 'apt-get build-dep mythtv' problem?
> 
> What's the story on "cross packaging" I think that's what it's called. I
> read mention of it when trying to figure out what was going on with
> e2fsprogs? I'm guessing it has something to do with having different
> versions from the "tree" on the same machine causing conflicts.

Often times, I will install .deb's from unstable because the versions in testing and stable don't fit my needs.  This can be somewhat tricky when it comes to dependencies.  Basically, when you download the package and attempt to install it using dpkg, if there are unmet dependencies, dpkg will not continue with the package installation.  From there, you can try to download the dependent packages, and hope that those packages don't require newer versions of packages *they* depend on.  In some cases, this works well, and in others, it doesn't, and you'll be running back to the ftp site to download the required dependencies just to find out you have more unmet dependencies.

For the record, I try not to do this often, as it can seriously break a system.  I also plan on how I can roll back, *just in case*!  When doing this, it's *very* rare that I use the --force option with dpkg.

> Does apt have the intelligence to not mix and match incompatible items or is
> that more of an end user function?

apt-get only fetches the packages.  It relies on dpkg to perform the package installation and to check for dependencies.  As I've stated above, you can mix packages from one tree with another by downloading the packages manually and installing them a la "dpkg -i somepackage.deb".  If there are unmet dependencies, dpkg will not install the package and tell you what it needs.

As an alternative, you can create a chroot environment, and you can install a different version of debian in the chroot environment.  This keeps it all separated from the version you're currently running.

- Ken