pip install --find-links dist no longer prefers local over PyPI (fails maturin CI)

[chrisjsewell]

Description

Since pip v20, if you have a package built locally and on PyPI at the same version,
the following command will prefer installing the PyPI package than the local build:

pip install mypkg --find-links dist --force-reinstall

If the local package has a newer version then that will be installed

This is a problem for e.g. maturin generate-ci github --pytest (PyO3/maturin#1680),
which builds the wheel (per OS), then installs and runs pytest.

It means that, for every PR, you have to ensure that you have bumped the version.

Expected behavior

Either the behaviour is reverted, or there is a separate flag to enforce the behaviour, e.g. --prefer-local

pip version

23.1.2

Python version

3.10

OS

Linux

How to Reproduce

1. Upload a package to PyPI
2. Build the package wheel locally, without changing the version, into a dist folder
3. Run pip install mypkg --find-links dist --force-reinstall

Output

With pip-23.0.1

Looking in links: dist
Collecting markdown_it_pyrs
  Downloading markdown_it_pyrs-0.2.0-cp310-cp310-manylinux_2_17_x86_64.manylinux2014_x86_64.whl (2.1 MB)
     ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ 2.1/2.1 MB 15.2 MB/s eta 0:00:00
Installing collected packages: markdown_it_pyrs

with pip-19.3.1

Processing ./dist/markdown_it_pyrs-0.2.0-cp310-cp310-manylinux_2_17_x86_64.manylinux2014_x86_64.whl
Installing collected packages: markdown-it-pyrs
Successfully installed markdown-it-pyrs-0.2.0

Code of Conduct

• I agree to follow the PSF Code of Conduct.

[pfmoore]

Pp never preferred local over PyPI. It has always considered two copies of a package with the same name and version as being interchangeable. So unfortunately, without realising it, you have been relying on an accident of the current implementation (which appears to have changed).

If you want pip to prefer the local copy, you need to give it a higher version than the one on PyPI.

[baseplate-admin]

Hi, could we have a flag in pip that prefers local package instead of remote?

It's very test a pre release package in the CI/CD without this behavior of pip.

Thanks a bunch.

[pfmoore]

Hi, could we have a flag in pip that prefers local package instead of remote?

See #8224

In the meantime, uv provides an index strategy option which might do what you want.