mocker's use of __import__ causes double module initialization

[David Glick]

Mocker uses the idiom object = __import__(module_path, {}, {}, [""]) to import a module and get a reference to it. This has the unwanted side effect of causing the module to be re-initialized if it was already imported, as described in http://bugs.python.org/issue2090 ... that's bad if the module being imported has import-time side effects.

The Python 2.6 documentation now recommends a different idiom for use in this situation:

"If you simply want to import a module (potentially within a package) by
name, you can get it from sys.modules:
>>> import sys
>>> name = 'foo.bar.baz'
>>> __import__(name)
<module 'foo' from ...>
>>> baz = sys.modules[name]
>>> baz
<module 'foo.bar.baz' from ...>
"

I'm attaching a patch (against mocker 0.10.1) which makes mocker use this approach.

[Gustavo Niemeyer (niemeyer)]

Thanks for the patch David. I've applied the change in revision 58.

In comparison to your patch, I've just reused the module_path variable.

This will be in Mocker 0.15 in a moment.

[David Glick (davisagli)]

Thanks for merging and releasing this. Will the 1.0 release be posted to PyPI?

[Gustavo Niemeyer (niemeyer)]

You're welcome, David. That's been done as well.