Checking deb dependencies against the current system

Question

I know I can list the .deb's dependencies using dpkg --info, but is there any automated way to check those dependencies against the current system? What I'm interested in, the status: whether the package will be cleanly installed, or will it fail.

Answer 1

According to the manual: dpkg -i --force-bad-path --dry-run foo.deb. However, it doesn't work, a bug was filed about this 10 years ago.

There is a corresponding option in apt-get and aptitude, but that only applies to packages obtained via apt.

Answer 2

Here's a way which is very hackish but does work, sort of.

Make sure you're not root, or you risk overwriting some system files.
Create a temporary directory and change to it.

mkdir root
cp -as /var/lib/dpkg .
rm dpkg/lock dpkg/triggers/Lock
fakeroot dpkg --force-not-root --force-bad-path --admindir=dpkg --instdir=root --log=log -i mypackage.deb

This will unpack the package and then complain about any missing dependencies on stderr. It's likely to return a nonzero status even if there are no missing dependencies because of a failing postinst script.

I haven't tried with a package that has a preinst script, it's possible that dpkg will give up before checking dependencies.