Debian – Using apt or aptitude to get version information about an uninstalled package

There is a recent enough version of xdebug in squeeze (the next release of Debian, which will be ready any month now). It doesn't have an official backport to stable (otherwise the backport would be listed on the xdebug package search page). The binary package depends on a recent version of PHP, but you should be able to compile the source package on lenny, since its build dependencies are satisfiable on lenny. Here's a recipe for building the package:

1. Download the three files (.dsc, .orig.tar.gz, and .debian.tar.gz). Since this is a punctual need, just do it manually.
2. Install the build dependencies (here debhelper and php5-dev) with apt-get or aptitude. Also install the basic set of development packages; the build-essential package will pull them all. Also install fakeroot.
3. Unpack the source: dpkg-source -x xdebug_2.1.0-1.dsc and change to the source directory: cd xdebug-2.1.0.
4. (You can skip this step if you don't make any change in the source package.)
   Edit the debian/changelog file to add a new changelog entry. This is easily done in Emacs:
   • make sure the dpkg-dev-el package is installed;
   • open debian/changelog in Emacs;
   • use C-c C-a to add an entry;
   • choose a new version number (here 2.1.0~user394+1 would be a reasonable choice, following the pattern used by the official backports);
   • write a log entry (e.g., backport to lenny, describe the changes you made);
   • use C-c C-c to finalize the entry.
5. Compile the package: dpkg-buildpackage -rfakeroot -us -uc
   If you have a PGP/GPG key, don't pass -us -uc and enter your passphrase if prompted to cryptographically sign the packages.
6. Profit Install the binary package.

To summarize the steps:

wget http://ftp.de.debian.org/debian/pool/main/x/xdebug/xdebug_2.1.0{.orig.tar.gz,-1.{dsc,debian.tar.gz}}
sudo aptitude install build-essential fakeroot debhelper php5-dev
dpkg-source -x xdebug_2.1.0-1.dsc
cd xdebug-2.1.0
# patch as necessary
emacs debian/changelog # not necessary if unpatched
dpkg-buildpackage -rfakeroot -us -uc
dpkg -i ../php5-xdebug_2.1.0_*.deb

The files list for that package is stored in /var/lib/dpkg/info/gnome-themes-standard-data.list; it is quite surprising this is anything other than a normal file.

I'd suggest ls -l or stat on it, to figure out what it is. If you can explain why its something other than a plain file (say, you symlink'd it somewhere), then undo that. If you didn't do anything to it, or its showing as something crazy, then I suggest an fsck.

If its missing entirely, you can probably grab a new copy from the .deb (extract it using dpkg-deb or ar and tar), but that could leave some cruft on your system (if the installed list didn't match exactly what was in the one from the package).