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Showing posts from November, 2014

A small caution when using virtualenvs

Virtualenvs are a great way to test and develop code in insulated containers. My main use case is to have an insulated environment where I can mock install a package I'm developing and ensure that I've taken care of all the dependencies so that a stranger can use the package as is. The virtualenvwrapper package is a great utility that simplifies managing multiple virtual environments.

One caution I have to observe is that packages installed out side the virtual environment can interfere in ways that make behaviors inside the virtual env very mysterious. For example, before I started using virtual environments seriously I had installed the nose and tox modules in my base python install. A month or so afterwards I had created a new test environment and was doing pip install -e . to test whether a package I was writing would install correctly on a fresh environment.

Everything installed fine, including an external package A my code needed. But, when I went to run nosetests or t…

git merge

I'm so used to git merge doing the right thing re: merging files - and possibly used to working mostly by myself - that when git merge fails I always expect something messy has happened. However, just now, I got a merge complain that amounted to this:

from setuptools import setup, find_packages setup( ... some things ... <<<<<<< HEAD ext_modules=cythonize('lib/*.pyx'), entry_points={ # Register the built in plugins .... # Command line scripts .... } ) ======= install_requires= .... cython_ext='lib/*.pyx' ) >>>>>>> origin/fix_setup
I was surprised since the changes I made and my colleague made were simple and non-overlapping. They just need to come in sequence.

I took a look at the git merge documentation which said

When both sides made changes to the same area, however, Git cannot randomly pick one side over the other, and asks you to resolve i…