Summary

Let's say our project is set up like this:

proj/
- pyproject.toml
- requirements.txt
foo.lib/
  - pyproject.toml

And our requirements.txt contains:

-e file:foo.lib

That path for foo.lib in requirements.txt is incorrect, because the path should be relative, e.g. ../foo.lib.

However, instead of saying that the path is wrong, uv complains that:

error: Couldn't parse requirement in `requirements.txt` at position 3
  Caused by: Expected path (`foo.lib`) to end in a supported file extension: `.whl`, `.tar.gz`, `.zip`, `.tar.bz2`, `.tar.lz`, `.tar.lzma`, `.tar.xz`, `.tar.zst`, `.tar`, `.tbz`, `.tgz`, `.tlz`, or `.txz`
file:foo.lib
^^^^^^^^^^^^

Presumably uv is treating the path as a file because of the .lib at the end.

Contrast this with the error message when we replace the . with a _:

error: Distribution not found at: file:///private/tmp/test/foo_lib

This is a lot better. (Tho it does require you to know what a "distribution" is.)

Steps to reproduce:

1. uv init test && cd test
2. echo "-e file:foo.lib" >> requirements.txt
3. uv add -r requirements.txt

Platform

Darwin 24.6.0 arm64

Version

uv 0.9.6 (Homebrew 2025-10-29)

Python version

Python 3.10.16