How to solve RPMs created by Alien having file conflicts

Thursday, February 23rd, 2017

I generate release packages for my software with Alien, which amongst other things converts .deb packages to .rpm.

On Fedora 24 however, the generated RPMs cause a small problem when installed with Yum:

Transaction check error:
  file / from install of cfgtrack-1.0-2.noarch conflicts with file from package filesystem-3.2-20.el7.x86_64
  file /usr/bin from install of cfgtrack-1.0-2.noarch conflicts with file from package filesystem-3.2-20.el7.x86_64

There’s a bit of info to be found on the internet about this problem, with most of the posts suggesting using rpmrebuild to fix it. Unfortunately, it looks like rpmrebuild actually requires the package to be installed, and since I don’t actually use a RPM-based system, that was a bit of a no-go.

So here’s how to fix those packages manually:

First, use Alient to generate a RPM package folder from a Debian package, but don’t generate the actual package yet. You can do so with the -g switch:

alien -r -g -v myproject-1.0.deb

This generates a myproject-1.0 directory containing the root fs for the package as well as a myproject-1.0-2.spec file. This spec file is the actual problem. It defines directories for paths such as / and /usr/bin. But those are already provided by the filesystem package, so we shouldn’t include them.

You can remove them from a script using sed:

sed -i 's#%dir "/"##' myproject-1.0/myproject-1.0-2.spec
sed -i 's#%dir "/usr/bin/"##' myproject-1.0/myproject-1.0-2.spec

This edits the spec file in-place and replaces the following lines with empty lines:

%dir "/"
%dir "/usr/bin/"

The regular expressions look somewhat different than usual, because I’m using the pound (#) sign as a reg marker instead of “/”.

Finally, we can recreate the package using rpmbuild:

cd myproject-1.0
rpmbuild --target=noarch --buildroot /full/path/to/myproject-1.0/ \
         -bb cfgtrack-$(REL_VERSION)-2.spec

The resulting package should install without errors or warnings now.