use of base python in pep517 builds breaks eg pydantic-core

[dimbleby]

Bug Description

#2094 arranged that maturin passes around the base python interpreter, rather than the python interpreter associated with the isolated build environment.

but then build-requirements declared in projects are not available to that interpreter

this causes the failure reported in pydantic/pydantic-core#1352, per pydantic/pydantic-core#1352 (comment)

Your maturin version (maturin --version)

1.6.0

Your Python version (python -V)

3.12

Your pip version (pip -V)

n/a

What bindings you're using

pyo3

Does cargo build work?

• Yes, it works

If on windows, have you checked that you aren't accidentally using unix path (those with the forward slash /)?

• Yes

Steps to Reproduce

• git clone [email protected]:pydantic/pydantic-core.git
  • eg v2.20.0 will work as a tag to reproduce the issue
• create and activate virtual env eg uv venv -p python3.12 ~/.virtualenvs/foo && workon foo
• install build eg uv pip install build
• python -m build

[dimbleby]

fyi @messense