environment `PYTEST_CACHE_DIR_BASE` for better share location

[loynoir]

What's the problem this feature will solve?

Current

$ cd /path/to/project/1
$ export PYTEST_ADDOPTS="-o cache_dir=/build/pytest_cache_dir_base/${PWD:?}"
$ uv run pytest

$ cd /path/to/project/2
$ export PYTEST_ADDOPTS="-o cache_dir=/build/pytest_cache_dir_base/${PWD:?}"
$ uv run pytest

$ cd /path/to/project/3
$ export PYTEST_ADDOPTS="-o cache_dir=/build/pytest_cache_dir_base/${PWD:?}"
$ uv run pytest

Describe the solution you'd like

environment PYTEST_CACHE_DIR_BASE for better share location

$ export PYTEST_CACHE_DIR_BASE="/build/pytest_cache_dir_base"

$ cd /path/to/project/1
$ uv run pytest

$ cd /path/to/project/2
$ uv run pytest

$ cd /path/to/project/3
$ uv run pytest

Alternative Solutions

Additional context

[RonnyPfannschmidt]

Cache is used for last failed and other project specific plugins

This proposal as is will just break

[loynoir]

I think, the not polluting source dir convention is actually across languages.

And also the ${PREFIX}/${absolute_path}.{generated_suffix} convention.

https://docs.python.org/3/using/cmdline.html#envvar-PYTHONPYCACHEPREFIX

$ ls ${PYTHONPYCACHEPREFIX:?}/absolute/path/to/__init__.cpython-313.pyc
${PYTHONPYCACHEPREFIX:?}/absolute/path/to/__init__.cpython-313.pyc

https://docs.deno.com/runtime/reference/env_variables/#special-environment-variables

$ ls ${DENO_DIR:?}/gen/file/absolute/path/index.ts.js
${DENO_DIR:?}/gen/file/absolute/path/index.ts.js

https://stackoverflow.com/questions/18826789/cmake-how-to-set-the-build-directory-to-be-different-than-source-directory#24435795

cd /path/to/my/build/folder
cmake /path/to/my/source/folder

[RonnyPfannschmidt]

#1089 is the prior issue for solving that - we need a design for this to