Python: Resolving Version Incompatibilities (Quick)
Fixing version issues in seconds instead of hours
pip
has a variety of useful features from managing its config, outputting installed packages, and checking for updates. However, I would say the most useful feature by far is `pip check
` and the new dependency resolver introduced in `20.3
`. The dependency resolver makes it much easier and more likely to correctly determine version combinations without dealing with compatibility issues. This is especially useful when a large portion of Python projects do not provide an output of `pip freeze
` along with the version of Python they were developing on.
pip check
`pip check
` is a command that validates whether installed packages have compatible dependencies. A number of Python modules have specific requirements depending on the version of other modules or Python itself. For example, pandas has numpy
as a dependency. However, for Python 3.11, numpy
must be version `1.23.2
` or higher, while for all previous versions, that range is extended to `1.21.6
`. This is, of course, not to mention that previous versions of Python will have different modules which support that version. With an exponential number of interactions, there is likely to be some level of incompatibility. As such, `pip check
` provides a good way to list those incompatibilities when they appear.
Using the Dependency Resolver Effectively
The best way to use the dependency resolver is to have a few strict requirements, with all others being loose. For example, if I had pandas
and numpy
as a dependency, my requirements.txt
might initially look like this:
pandas==2.0.1
numpy
This will tell the resolver to use version `2.0.1
` of pandas
and then use the highest, compatible version of numpy
. The dependency resolver will attempt to find the highest version of a module which is compatible with all other modules. Modules may have experimental packages or be in beta when a researcher uses them. By declaring a module with a known upper bound on the version, you can let the dependency resolver take care of the rest.
Some Additional Thoughts
Previous Papers I Reviewed
I wasn't aware of the new dependency resolver when I initially reviewed research papers for my reproducibility work in late 2022. However, the machine I was testing on used Python 3.8.10 with pip 20.0.2, which was before the introduction of the dependency resolver alpha in 20.1b1. As such, I will be reviewing the papers I spent hours trying to fix the version incompatibilities for once again. Reviewing and fixing your prior work is my responsibility, after all.