Note: This script is not developed nor endorsed by the Python Packaging Authority (PyPA) or other official Python body.
$ requirements_wayback_machine -r requirements.txt -d 2021-02-03
# requirements_wayback_machine: reference date 2021-02-03
# requirements_wayback_machine: torch<=1.7.1
torch
# requirements_wayback_machine: torchvision<=0.8.2
torchvision
# requirements_wayback_machine: imageio<=2.9.0
imageioInstalling correct dependencies for an older Python project can be tricky, since
pip install -r requirements.txt can easily install a package version that is too recent and
incompatible with the old project. This can happen even if the requirements.txt file
specifies an exact version (eg. torch==1.7.1), since Python packages often only specify
minimum versions of their dependencies (which does not prevent a new major dependency version
to be installed).
One solution to this problem is exact specification of all transitive dependencies as provided
by pip freeze or Pipenv/Poetry lockfiles. If you don't have a lockfile, this is where
Requirements.txt Wayback Machine comes in to tell you what was the last available version
of each dependency by given date. Presumably at some time in the past,
pip install grabbed the correct versions, so giving an approximate date when the project
was working will help you pin the correct versions.
Tip: If you're still having trouble after adding constraints for maximum versions for all
entries in your requirements.txt, try listing all transitive dependencies with pip freeze
and running Requirements.txt Wayback Machine again on this larger requirements.txt
(a suggestion by u/hai_wim on Reddit). Note that you will need to remove the == exact
constraints that pip freeze adds before doing this (the Wayback Machine is trying to satisfy the existing constraints,
so using == doesn't really make sense, it would find no suitable version if the == version
is too new).
$ pip install requirements-wayback-machine$ requirements_wayback_machine -r <path_to_requirements.txt> -d <YYYY-MM-DD>For more information and options, run requirements_wayback_machine -h.
Example:
$ cat requirements.txt
torch
torchvision
imageio
$ requirements_wayback_machine -r requirements.txt -d 2021-02-03
# requirements_wayback_machine: reference date 2021-02-03
# requirements_wayback_machine: torch<=1.7.1
torch
# requirements_wayback_machine: torchvision<=0.8.2
torchvision
# requirements_wayback_machine: imageio<=2.9.0
imageioMIT - see LICENSE.txt.