Since I just stumbled upon this myself in the documentation , it is probably better not to getbrew install inside the active virtualenv at all. To quote from the above documents:
A WARNING. When you brew install formulas that provide Python bindings, you should not be in an active virtual environment.
virtualenv , , brew . Homebrew - Python Homebrew, - .
Virtualenv , "" (, ) - virtualenv.
, , , , Python, . , brew install , deactivate.