Thus far the discussion on specifying dependencies is mainly on the format. I think another topic related to specifying deps is important to have at this point, and that is whether the chosen format should be “ready” in case we want to support specifying native dependencies or even consider cross-compilation.
One thing I would really like to see in the future is a a field where one can list the run-time executables it expects, as well as run-time libraries that are dlopen’ed. In Nixpkgs we commonly need to patch such references, which is quite a pain. With conda that should also be done, though I don’t know how much effort is put into it there. I imagine for other distro’s it also becomes easier this way to compute what native packages should be added as dependencies.
I imagine starting off with two sets:
-
dependencies-runtime-executablesis a list of executables -
dependencies-runtime-librariesis a list of libraries
Then, in the code, instead of directly using say subprocess.run with the executable name or find_library with the library name, one uses something like dependencies.executables("bash") and dependencies.executables("archive"). The dependencies are stored, like we do now with entry points, in a file in the dist-utils folder. That way downstreams can patch the references in that one file.
Why did I not include build-time dependencies here? Because those are the responsibility of the back-end. One could argue that’s the case for the pure-Python dependencies as well, but those are also solely run-time dependencies.
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