Why does pip installing a django module update my django version?

Question

I am working down a list of module dependencies for a django project I have inherited. I am setting up a local environment on a Windows 7 machine.

One of the first requirements is django==1.4.1, so I am installing this with pip, like this;

pip install -U django==1.4.1

This works fine. But when I get to some other items, like django-nose, and run

pip install -U django-nose==1.1

then I notice in the console output that it is updating my copy of django to 1.6.5

I can of course go back and backdate to django==1.4.1 afterwards, but I guess there is a reason for the update, and I'd like to understand it. I want my local environment to match the staging environment I am going to deploy to, is it ok to backdate my version, or is there a way of telling pip not to update django for me? Or is the newer version a requirement of the module I am installing?

Answer 1

The -U switch tells pip to upgrade the package and dependencies to their latest available version:

-U
Upgrade all packages to the newest available version. This process is recursive regardless of whether a dependency is already satisfied.

Emphasis mine.

django-nose depends on nose and Django , so these are upgraded to their latest versions, you did not explicitly pin them.

Use --no-deps if you don't want to upgrade dependencies:

pip install -U --no-deps django-nose==1.1

or better still, don't use -U . You already pinned django-nose , so the -U switch is ineffective.

Answer 2

The switch -U means: "Upgrade all packages to the newest available version. This process is recursive regardless of whether a dependency is already satisfied."

So you just forced the update yourself.