1. "it" ? What is "it"? Jvm? Rakudo?
2. How do I fix this, do I have to uninstall every jvm, or rakudo, or ....
3. Error message really aught to have a bug number at very least.
4. Ideally, this should just be some kinda of blocker, but eh, or maybe there needs to be some sort of sandbox thing that hides rakudo from itself so it can't tell.
TL;DR -> WAT?
>>> Running pre-merge checks for dev-lang/rakudo-2016.04-r1
* ERROR: dev-lang/rakudo-2016.04-r1::gentoo failed (pretend phase):
* Rakudo is known to fail compilation with the jvm backend if it's already installed.
* Call stack:
* ebuild.sh, line 133: Called pkg_pretend
* rakudo-2016.04-r1.ebuild, line 36: Called die
* The specific snippet of code:
* die "Rakudo is known to fail compilation with the jvm backend if it's already installed."
* If you need support, post the output of `emerge --info '=dev-lang/rakudo-2016.04-r1::gentoo'`,
* the complete build log and the output of `emerge -pqv '=dev-lang/rakudo-2016.04-r1::gentoo'`.
!!! When you file a bug report, please include the following information:
GENTOO_VM= CLASSPATH="" JAVA_HOME="/etc/java-config-2/current-system-vm"
and of course, the output of emerge --info =rakudo-2016.04
* The complete build log is located at '/var/log/portage/build/dev-lang/rakudo-2016.04-r1:20160528-104812.log.gz'.
* For convenience, a symlink to the build log is located at '/var/tmp/portage/dev-lang/rakudo-2016.04-r1/temp/build.log.gz'.
* The ebuild environment file is located at '/var/tmp/portage/dev-lang/rakudo-2016.04-r1/temp/die.env'.
* Working directory: '/usr/lib64/python3.5/site-packages'
* S: '/var/tmp/portage/dev-lang/rakudo-2016.04-r1/work/rakudo-2016.04'
For NQP: Unmerge both dev-lang/nqp and dev-lang/rakudo before you attempt to reinstall it.
For Rakudo: Unmerge dev-lang/rakudo before you attempt to reinstall it.
In the next revisions, the warning will be non-fatal, since it's difficult to predict when the build/install will fail.
The issues here are the backends, moarvm and jvm. In various combinations of those backends, both NQP and Rakudo fail to compile with previous installations present on the system.
This is a workaround for the time being, hence I will leave the bug open.