Building for Gigalixir on windows error: elixir_buildpack.config: line 1: $'\377\376elixir_version=1.14.0': command not found

I have been unable to get the build working for Gigalixir. Following the tutorial exactly as written for a “mix” project, I would get:

Unable to select a buildpack

and then the process would exit.

After creating a .buildpacks (just using the default one also provided), I get this error

/tmp/build/elixir_buildpack.config: line 1: $'\377\376elixir_version=1.14.0': command not found

This seems to be a windows-file-system thing, but I was unable to run wsl on my machine (edit: I was able to try running the commands from wsl, and no dice, they fail with the exact same message), and I feel like this would be a more common problem (I can’t find this exact error message anywhere) if it were just a windows-general problem.
Removing all but GitHub - gigalixir/gigalixir-buildpack-mix from the buildpacks file did allow everything to actually get to gigalixir, but without the heroku buildpack it predictably fails to even start.

Ok, so my first instinct was correct. I managed to get wsl working, and after explicitly rewriting the files, it did work. I think the docs should be amended to remove the “windows” option, as the current tools are clearly not able to work on windows.

This is a byte-order mark (BOM) indicating the file is UTF16LE. It appears to be confusing the buildpack’s use of source to load the configuration.