pex lock subset fails for --style universal locks when it traverses dependencies de-selected by environment markers tied to --target-system and --interpreter-constraint.

[jsirois]

Discussed in #2682

^{Originally posted by lecardozo February 14, 2025}
I'm trying to use the recently released pex lock subset subcommand to extract a subset of the dependency tree of an existing lockfile but I'm getting an error which I'm not sure is expected:

Command

$ pex lock subset --lock lockfile.lock -r requirements.txt
There is no lock entry for colorama in lockfile.lock to satisfy the transitive 'colorama; platform_system == "Windows"' requirement.

Initially I thought this was happening due to the lack of a --complete-platform specification — since there is a environment marker for a different platform associated with this dependency —, so I included the platform JSON file (generated by pex itself), but the error still happens.

Question

Is this expected behavior? Should the lockfile indeed have an entry for this dependency?

Extra

• The lockfile was generated by pants 2.23.0 (which I think uses pex 2.16.2 for generating the lockfile according to source)
• Pex (used for running the command) version is 2.32.1
• The lockfile was generated on a Mac
• The complete platforms was generated on a docker container to include only linux
• The lockfile itself
• Complete platforms used: linux-x86_64.json

[jsirois]

Ok, this is enough to repro:

:; pex3 lock subset --lock lockfile.json click
There is no lock entry for colorama in lockfile.json to satisfy the transitive 'colorama; platform_system == "Windows"' requirement.

[jsirois]

The issue here was --target-system filtering that occurs in pex3 lock {create,sync} for --style universal locks not being respected in pex3 lock subset. Another issue lurking was ditto, but for --interpreter-constraint in --style universal locks. Trying to subset click from the example lock stresses both of these misses.

[jsirois]

#2684 fixes both of these misses and brings pex3 lock subset (and --elide-unused-requires-dists) up to par with pex3 lock {create,sync} --style universal.

[jsirois]

@lecardozo the fix is released in v2.33.1.
You can upgrade Pants to use this release (if needed), with these instructions: https://www.pantsbuild.org/stable/docs/python/overview/pex#setting-pex-and-pip-versions