Erich Schubert

>This is what we did with Dart's package manager[1]. It works like Bundler where it finds a single set of package versions that satisfy all of the constraints and there are no duplicate packages. Constraint solving is the status quo, and I am strongly opposed to it. Rather than saying "I want foo >= 1.0" in a package manager, you should have the build system test the environment for the features you need. This is what the Autotools and other build systems that have been around for decades do. This way, the project isn't tied to a single package manager and, in the case of free software, greatly eases the burden on package maintainers that want to add your software to their distribution. Functional package management doesn't need constraint solving because every package in the system precisely describes itself: exactly which dependencies are needed for build-time and runtime (which precisely describe themselves, recursively, all the way down to libc), precisely which source code (tarball/directory/whatever + checksum), and the exact build script that turns that source code into a (hopefully bit-reproducible) binary. There's no constraint solving to determine what the dependency tree is, it's already been encoded in the package objects themselves. This is what any robust package manager should enable, but the only two that I know of that do this are Nix and GNU Guix. >The problem then is now your language has a dependency on an outside package manager, one which is…