Cascading dependency resolution in boto3

[theherk]

I'm not sure how the dependency resolution is supposed to work in pip, but I think I have found a problem.

I am referencing this issue: boto/boto3#270

As of 22 Sep jmespath was bumped to version 0.8.0 from 0.7.1. This is causing a problem. boto3 requires 'jmespath>=0.6.2,<1.0.0', so it installs the latest version (0.8.0). It also requires botocore, which requires 'jmespath==0.7.1'.

When pip gets to this point, having already installed 0.8.0, it would be nice if it realized that the installed jmespath 0.8.0 does not satisfy this requirement, so reinstall with the required version, knowing it still satisfies boto3 requirement of 'jmespath>=0.6.2,<1.0.0'. But it doesn't.

Is this not possible?

[qwcode]

it's an open issue to handle this better (#988 )

in the mean time though, you can work around this yourself (once you realize what's going on) using requirements file overrides.

see case #2 here: https://pip.pypa.io/en/latest/user_guide/#requirements-files