All of the ROS-related ebuilds should have the python3 use flags enabled. It may not yet be officially supported on all packages, but from experience with Fedora (which has long abandoned python2 support), we know that much (most?) of ROS works fine with python3. Not even offering python3 support on Gentoo precludes the testing that is sorely needed to finally get rid python 2. Reproducible: Always
? This should be the case for some time already. Please reopen with actual examples.