Autoreload can't handle module / __main__

[ghost]

Originally reported by: Anonymous

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I try to run python -m mymodule (and mymodule/ contains __main__.py). The module then spawns a CherryPy server. Everything works until it tries to reload itself, where it tries to run /path/to/python mymodule/__main__.py, without importing mymodule. This makes my module to throw various ImportErrors that claim mymodule cannot be found.

Could you share any tips how to organize the code, or change the way I run the server, to make reloading work?

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• Bitbucket: https://bitbucket.org/cherrypy/cherrypy/issue/1411

[jaraco]

My guess is that the autoloading feature is simply not aware of the -m entry technique. I was not aware that python -m foo would implicitly import the package.

$ mkdir foo
$ cat > foo/__main__.py
print("Ran __main__")
import foo
$ python -m foo
Ran __main__
$ cat > foo/__init__.py
print("imported foo")
$ python -m foo
imported foo
Ran __main__

I'm pretty sure you can work around the issue by adding import mymodule in your __main__. Did you try that? If that doesn't work, what happens?

[sevmonster]

Didn't see that this had an issue already.

See #1436, both issues are caused by the same situation.
This bug has been around for a few years now.

[jaraco]

I suspect that the autoreloader functionality has never supported launching as -m, which I believe is the underlying issue here. To work around the issue, you probably need to avoid launching using -m.

If someone would like to devise a fix, I suspect using the runpy module, mentioned in PEP 338 might be way to do it.

[batterseapower]

Bit tricky to fix because of http://bugs.python.org/issue14208