With portage 2.2_rc12:
[ebuild R ] sys-apps/portage-2.2_rc12 USE="doc -build -epydoc (-selinux)" LINGUAS="-pl" 0 kB
After a long compile to upgrade gcc to 4.3.2 from 4.3.1:
[ebuild NS ] sys-devel/gcc-4.3.2 [3.3.6-r1, 4.2.2, 4.2.3, 4.2.4, 4.3.1-r1] USE="fortran gcj gtk (multilib) multislot nls objc objc++ objc-gc openmp (-altivec) -bootstrap -build -doc (-fixed-point) (-hardened) -ip28 -ip32r10k -libffi -mudflap (-n32) (-n64) -nocxx -test -vanilla" 0 kB
installation failed because of detected file collision:
* Searching all installed packages for file collisions...
* Press Ctrl-C to Stop
which is fair enough because collision-protect is set in FEATURES in /etc/make.conf.
However, rather than a complete re-compile after editing /etc/make.conf to remove collision-protect from the list of FEATURES (or the equivalent of prepending it to the emerge command environment, i.e. FEATURES="-collision-protect" emerge gcc), I tried using the lower-level ebuild command itself to complete the installation.
FEATURES="-collision-protect" PORTAGE_TMPDIR=/var/tmp ebuild gcc-4.3.2.ebuild qmerge
failed with the same file collision detection messages.
I managed to make a package:
FEATURES="-collision-protect" PORTAGE_TMPDIR=/var/tmp ebuild gcc-4.3.2.ebuild package
FEATURES="-collision-protect" emerge -k =sys-devel/gcc-4.3.2
again failed with the same file collision errors.
Using the latest stable version of portage (126.96.36.199) allowed the 'ebuild ... qmerge' command to work as expected whilst the 'emerge -k ...' command also completed OK with portage 2.2_rc11, so it looks as if the bug is between rc11 and rc12 of portage 2.2.
Consider that a very useful feature for now.
*** This bug has been marked as a duplicate of bug 216241 ***