How can I upgrade specific packages using pip and a requirements file?

Question

I'm using pip with a requirements file, in a virtualenv, for my Django projects. I'm trying to upgrade some packages, notably Django itself, and I'm getting an error about source code conflicts:

Source in <virtualenv>/build/Django has version 1.2.3 that conflicts with Django==1.2.4 (from -r requirements/apps.txt (line 3))

That's after updating the version number of Django from 1.2.3 to 1.2.4 in my requirements file. I'm using this command to actually do the upgrade:

pip --install --upgrade -E `<virtualenv dir`> --requirement `<requirements file`> 

I can't find any flag that triggers a total package re-download. I even tried running an uninstall command first, and then the install, but no dice. Am I missing something?

Answer 1

I ran the following command and it upgraded from 1.2.3 to 1.4.0

pip install Django --upgrade 

Shortcut for upgrade:

pip install Django -U 

Note: if the package you are upgrading has any requirements this command will additionally upgrade all the requirements to the latest versions available. In recent versions of pip, you can prevent this behavior by specifying --upgrade-strategy only-if-needed. With that flag, dependencies will not be upgraded unless the installed versions of the dependent packages no longer satisfy the requirements of the upgraded package.