Subsequent sdist runs are reusing an old, cached wheel

Typically during development, your package’s version doesn’t change and pip will install a cached wheel built from an older sdist. For example:

nox > python -m pip install --constraint=.nox/unit-3-8-sdist/tmp/requirements.txt file:///Users/brechtm/Documents/Code/rinohtype/dist/rinohtype-0.5.3.tar.gz#egg=rinohtype
Collecting rinohtype
  Using cached rinohtype-0.5.3-py3-none-any.whl

A solution could be to pass --no-cache-dir to pip when installing the package, though that may cause issues with older pip versions.

[cjolowicz]

Fixed in #523

[brechtm]

When installing from an sdist, pip will first build a wheel from it. That wheel is cached, and reused when installing from an sdist with the same name/version. When you’re doing development, the package version typically doesn’t change, so you end up testing against an old version of your source code.

Hence, to reproduce:

• Make Nox (with nox-poetry) run tests using the sdist
• Introduce a breaking change in your source code
• Run tests again, which will succeed despite the breaking change