Folks,

I want to thank you all for providing the encouraging feedback and some great food for thought. Owing to your comments, I’m even more convinced that we can build a solid boundary enforcement tool for Elixir.

As a result of your comments, and the issues reported on the repo, I now realize that some of my original ideas were not on the right track. That’s actually a good thing! While I was a bit reluctant about sharing my work at such an early stage, I’m now happy that your review helped me discover some foundational problems so early on in the process.

So at this point, I’m increasingly leaning towards the following changes:

• allowing partial coverage (not all modules have to be a part of some boundary)
• switching to a decentralized solution
• prioritizing nested boundaries (boundaries within boundaries)

I plan on writing a detailed proposal, but I probably won’t make it this week, so I just wanted to let you know that I’m intensively thinking about this.

Now that Elixir 1.10 is released, I pushed the changed internals which rely on new compilation tracers. The new version requires Elixir 1.10, and the usage is slightly changed. See changelog and docs for details. I also decided to push the package to hex. The new version is 0.2.0. Those who are using the library but aren’t on Elixir 1.10 yet can use 0.1.0.

I finally found some time to make the proposal for the changes I’d like to do in boundaries. You can find it here. Looking forward to hear your feedback!

FYI, I started working on the proposed changes. See this comment for details.

Started working on the support for managing external dependencies. The idea is that you can do something like this:

defmodule MySystemWeb do
  use Boundary, externals: [ecto: [Ecto.Changeset]]
end

to restrain ecto modules only to Ecto.Changeset (and Ecto.Changeset.* if such exist). Other external deps are unrestrained.

Demo:

image814×340 36.1 KB

The code is pushed to GH master, but not yet published on hex, since I’d like to get feedback on the interface. Docs for the new feature are available here.