I am a developer of a R package. Recently, the R core team released version 4 of the R programming environment. This version introduces changes to the core of the language that can cause incompatibly issues with code written in version 3.x and version 4.x. I am requesting that the package maintainer of dev-lang/R create ebuilds that allow for slotted installs of R versions 3 and 4 so that I may test my code using either environments on the same system at least until the transition period to R version 4.x has stabilized.
Honestly, I doubt this is worth the effort. SLOTing a package is a massive undertaking, and removing it is the same massive undertaking again.
I have to agree. dev-lang/R is already "drive-by" maintained as it is. There's no one willing/able to slot it, write the eselect module, and figure out how everything that depends on R would continue to work.
I should mention that the *best* way to resolve these sorts of problems is by creating Gentoo packages for the R stuff, as in bug 96600. That project is admittedly dead, but it's the right idea. If your R package had an ebuild, it could just depend on <dev-lang/R-4.0 until you are able to update it.
