We could detect this sort of thing by running PhutilInfrastructureTestCase. I almost wonder if we should always run this test case?

I think it would take a little effort -- IIRC, we don't look for src/__tests__/ right now -- but I think it's reasonable to make that work and move the src/infrastructure/__tests__/ directory up.

I could also imagine writing some kind of arc make which happens during arc land to make sure artifacts like this are generated correctly, but that's a more significant undertaking.

Ideally we probably wouldn't be checking this stuff into the master repository at all, and would just build it for some kind of tarball release kind of thing, but doing that without creating huge barriers for users would require a lot more release/versioning/packaging infrastructure than we currently have.