[Question] mix depencency behavior

[Megzari Raphael]

Hi!

    There is an effort at the moment in NixOS to add mix dependency in the store. The idea being that a dependency with a particular version and name can be found and nix understands that a mix project has that particular dependency.

    Currently parsing the mix.lock can give the dependency tree.

    When building a particular dependency which has itself dependencies. How can mix be made aware of where those dependencies are?

    To clarify a little. `plug` has a dependency on `mime` `plug_crypto` and `telemetry`. Once those three dependencies have been compiled, when it's time to compile plug, how can I make mix understand where those dependencies are?

    Should the path of those dependencies be added to the `$ERL_LIBS` env var ?

    Should those compiled dependencies be placed symlinked under `_build/$MIX_ENV/lib` ?

    My understanding is that the compilation will have to happen with `mix compile --no-deps-check`.

   I couldn't find relevant documentation in mix, I would be interested in any pointers.

[Christopher Keele]

If you're executing Elixir code within the context of the mix project, you can invoke Mix.Project.deps_paths/{0,1} to figure this out.

[Megzari Raphael]

Thank you for your help.

After checking the mix code it seems that the ERL_LIBS is referenced. We are going to go with just adding dependencies paths to the ERL_LIBS for now. After testing it seems that the behavior works. Since the behavior is undocumented we won't be expecting it to be stable.

Thank you for the amazing software!