IMHO package managers should support having multiple versions of the same package at the same time. Not because anybody should be doing that, but because soone

IMHO package managers should support having multiple versions of the same package at the same time. Not because anybody should be doing that, but because sooner or later some conflict will arise that makes it unavoidable, and it's better to have first-class support for it, than to hack around it. For example, apt only allows one version per package, but that doesn't actually mean Debian is so lean and principled. When necessary, Debian stuffs package version in the package name.