New Python pip 20.1.1 changed requirements.txt format

In the latest nixpkgs revision, pip has been updated to 20.1.1. I noticed that when I use pip freeze. I don’t get the original requirements format anymore. Instead I get direct references: PEP 440 -- Version Identification and Dependency Specification |

Like this:

absl-py @ file:///build/absl-py-0.9.0/dist/absl_py-0.9.0-py3-none-any.whl

Any ideas why this change happened?

The old way of:


Was a lot more useful.

For the same reason we pass an url to our fetchers. There are more places than PyPI where packages can be found and so there is a need to describe where the packages can be found.