[Bug]: Dependency Resolution Failure when Upper Bound on Required Python Version

[mahyarmirrashed]

I noticed this error about a week ago when I switched over from poetry to uv. The dependency resolution fails when I set the upper bound of the required version in my pyproject.toml. (Yes, apparently this is a contentious decision, but I think I'll keep it.)

[project]
name = "test"
version = "0.0.0"
requires-python = ">=3.6,<4.0"
dependencies = []

[project.optional-dependencies]
dev = [
  "basedpyright>=1.17.0,<1.18.0; python_version>='3.8'",
  "pytest>=8.3.0,<8.4.0; python_version>='3.8'",
  "boto3-stubs[ecr,s3]>=1.35.0,<1.36.0; python_version>='3.8'",
  "types-paho-mqtt>=1.6.0,<1.7.0; python_version>='3.8'",
]

That TOML should give you what is needed to reproduce the error. Your local Python version shouldn't matter in reproducing this bug.

To fix it, removing <4.0 does allow uv to resolve the dependencies based on the local Python version, as expected.

[mahyarmirrashed]

❤️