[Distutils] How to eliminate on part of a package?

[John Thorvald Wodder II]

On 2018 Apr 25, at 16:02, Skip Montanaro <skip.montanaro at gmail.com> wrote:
> I recently ported a package to Python 3. The overall structure is
> pretty straightforward:
> 
> top/
>    client/
>        module.py
>    server/
>        server.py
> 
> There's more to it, but that's enough for demonstration. I am
> retaining Python 2.7 compatibility on the client side, but have
> dispensed with that business on the server. (I run the server, not my
> users.) Accordingly, I would like the py27 version of the package to
> not have a subpackage named "server".
> 
> I thought it would be easy peasy to just trim the server bits from
> setuptools.find_packages() in my setup.py file (I have
> 36.5.0.post20170921 of setuptools), something like this:
> 
> packages = setuptools.find_packages()
> if sys.version_info.major < 3:
>    packages.remove("top.server")
> 
> In either case, I pass the resulting list as the packages argument of
> setuptools.setup(...).
> 
> That doesn't work though. I get some sort of mish-mash where part of
> the top/server tree is copied, part not. I eventually get an error
> from a cp command, something about ".../server is not a directory".

If by "top/server tree" you mean that there are more subpackages under top.server (not just a server.py file as your diagram shows), then you need to filter out all of those subpackages as well, e.g.:

    packages = setuptools.find_packages()
    if sys.version_info.major < 3:
        packages = [
            pkg for pkg in packages
                if pkg != "top.server" and not pkg.startswith("top.server.")
        ]