exported category/pkg-x.y.z-r0::local not installing...

[CaptainBlood]

When exporting local repository containing a homebrewed category/pkg/pkg-x.y.z-r0.ebuild (which installed fine) to another system, destination host fails to install category/pkg/pkg-x.y.z-r0.ebuild.
Destination host only let install category/pkg/pkg-x.y.z.ebuild from the imported local directory.

I've encountered that situation many times in the past.
I concluded better is to avoid using -r0.
However I find it very handy to derive a non revised package, because gentoo portage tree doesn't.
So -r0 is always a free slot for local repository.

What makes one portage system allow to install an -r0 package ebuild when another doesn't?

Thks 4 ur attention, interest & support.
_________________
USE="-* ..." in /etc/portage/make.conf here, i.e. a countermeasure to portage implicit braces, belt & diaper paradigm
LT: "I've been doing a passable imitation of the Fontana di Trevi, except my medium is mucus. Sooo much mucus. "

[CaptainBlood]

Digging a little deeper has shown that removing unrevised ebuild in destination host allows revised ebuild to be installed.
However after-installing the revised ebuild on the destination host, emerge -1 category/package_name_only would fallback to unrevised ebuild if restored.

It looks like category/pkg-x.y.z < category/pkg-x.y.z-r0 on source system and category/pkg-x.y.z-r0 < category/pkg-x.y.z on destination system.

Source (old) and destination (new) hosts have been installed with many years interval.
I hardly believe it to be the source of the issue.

Could it be something in portage default configuration file(s)?

Thks 4 ur attention, interest & support.
_________________
USE="-* ..." in /etc/portage/make.conf here, i.e. a countermeasure to portage implicit braces, belt & diaper paradigm
LT: "I've been doing a passable imitation of the Fontana di Trevi, except my medium is mucus. Sooo much mucus. "