Empty string requirement should not be considered equal to version 0.0

[wimglenn]

Description

When using pip install pkg==, pip downloads and installs version 0.0 if it's in the index. I use importlib-metadata as an example because it has a 0.0 release in PyPI:

https://pypi.org/project/importlib-metadata/0.0/#files

Expected behavior

Something like:

$ pip install importlib-metadata==
ERROR: Could not find a version that satisfies the requirement importlib-metadata== (from versions: 0.0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 0.10, 0.11, 0.12, 0.13, 0.14, 0.15, 0.16, 0.17, 0.18, 0.19, 0.20, 0.21, 0.22, 0.23, 1.0.0, 1.1.0, 1.1.1, 1.1.2, 1.1.3, 1.2.0, 1.3.0, 1.4.0, 1.5.0, 1.5.1, 1.5.2, 1.6.0, 1.6.1, 1.7.0, 2.0.0, 2.1.0, 2.1.1, 2.1.2, 2.1.3, 3.0.0, 3.1.0, 3.1.1, 3.2.0, 3.3.0, 3.4.0, 3.5.0, 3.6.0, 3.7.0, 3.7.1, 3.7.2, 3.7.3, 3.8.0, 3.8.1, 3.8.2, 3.9.0, 3.9.1, 3.10.0, 3.10.1, 4.0.0, 4.0.1, 4.1.0, 4.2.0, 4.3.0, 4.3.1, 4.4.0, 4.5.0, 4.6.0, 4.6.1, 4.6.2, 4.6.3, 4.6.4, 4.7.0, 4.7.1, 4.8.0, 4.8.1, 4.8.2, 4.8.3, 4.9.0, 4.10.0, 4.10.1, 4.11.0, 4.11.1, 4.11.2, 4.11.3, 4.11.4, 4.12.0, 4.13.0, 5.0.0, 5.1.0, 5.2.0, 6.0.0, 6.0.1, 6.1.0, 6.2.0, 6.2.1, 6.3.0, 6.4.0, 6.4.1, 6.5.0, 6.5.1, 6.6.0)
ERROR: No matching distribution found for importlib-metadata==

pip version

23.1.2

Python version

3.11

OS

macOS and Linux

How to Reproduce

pip install importlib-metadata==

Output

$ pip install importlib-metadata==
Collecting importlib-metadata==
  Downloading importlib_metadata-0.0.tar.gz (6.2 kB)
  Installing build dependencies ... done
  Getting requirements to build wheel ... done
  Preparing metadata (pyproject.toml) ... done
Requirement already satisfied: setuptools in ./.venv/lib/python3.11/site-packages (from importlib-metadata==) (67.8.0)
Requirement already satisfied: wheel in ./.venv/lib/python3.11/site-packages (from importlib-metadata==) (0.40.0)
Building wheels for collected packages: importlib-metadata
  Building wheel for importlib-metadata (pyproject.toml) ... done
  Created wheel for importlib-metadata: filename=importlib_metadata-0.0-py2.py3-none-any.whl size=6329 sha256=4a4feb0b707f91415c4a972edb93cc271bea12ca6543b8d72a0361809a586abd
  Stored in directory: /home/wglenn/.cache/pip/wheels/62/4e/df/fab9dcd3d76cc5fa3e37b7d24fa156bc733836f1d682ebca80
Successfully built importlib-metadata
Installing collected packages: importlib-metadata
Successfully installed importlib-metadata-0.0

Workaround

other way to get list of versions without possibly getting a 0.0 release: pip install importlib-metadata==bogus

Code of Conduct

• I agree to follow the PSF Code of Conduct.

[pfmoore]

This should be fixed when we upgrade our vendored copy of the packaging library, as the new version treats an pkg== as an invalid requirement.

[uranusjr]

Merging into #11715.