Package collisions

When you encounter a package that is trying to install files that are already provided by another package (detectable with FEATURES=collision-protect for example) you have to fix this situation before you can commit the ebuild or, if you encounter this with an existing package, file a bug about that package (see below for a few exceptions). The reason file conflicts are critical is because if "foo" provides the file /usr/bin/example and "bar" is going to overwrite it, and later "bar" is unmerged, Portage will remove /usr/bin/example and it is therefore likely it will break "foo".

The most obvious fix is to add a blocking dependency to both packages that want to install that file, so they can't be installed at the same time. But unless there are also other reasons for those packages to block each other you should avoid this if possible and rather fix the package, which could include one or more of the following steps:

• Make "foo" (R)DEPEND on "bar" and not install the conflicting file.
• Remove conflicting files from "foo" in src_install or pkg_preinst.
• Move conflicting files into a new subpackage and make "foo" and "bar" both (R)DEPEND on that package.
• Change the location where "foo" or "bar" installs conflicting files.

In some cases conflicting files can't be really fixed or aren't critical, currently known exceptions are Perl module manpages (overwriting the ones from Perl itself) and CONFIG_PROTECT'ed files (which should still be fixed, but aren't critical as Portage won't overwrite them).