__main__.hy doesn't work like __main__.py

[Zirak]

(All snippets below tested with hy master and python 3.6.3)

When running a directory with a __main__ file, hy fails while python succeeds:

% ls
__main__.hy __main__.py
% python .
hey
% hy .
hy: Can't open file '.': [Errno 21] Is a directory

Same applies to egg files, but that may be its own independent problem.

Passing the -m flag does execute the __main__, unlike python:

% hy -m .
hy
% python -m .
python: Relative module names not supported

Fixing the first block is relatively simple: In cmdline, run_module already does the correct thing when running a directory/file according to the respective function in cpython.

However, making the 2nd block fail is a breaking change, as run_module does not do the same thing as the respective function in cpython (wraps runpy._run_module_as_main)

In the end, the question may be is this worth fixing on a lower level? Does hy want to copy the behaviour of run_file and run_module as implemented in cpython, or is it good enough to be able to run a directory/zip/whatever with a __main__?

[Kodiologist]

Huh, I didn't even know this Python feature existed. #459 might be related. Thanks for reporting.