I had this problem just now, and the issue was that I was referring to non-existent modules from an old pyproject.toml file that I had copied over to this new package in the [project.optional-dependencies]. So if you just get the dist-info folder created upon installation but not the actual package folder, check the pyproject.toml folder for errors, and specifically check to make sure that [project.optional-dependencies] does not list any modules that do not exist in your package.