BUG: Cython 3 Compatibility

[snowman2]

Error compiling Cython file:
------------------------------------------------------------
...

cdef void pyproj_context_initialize(PJ_CONTEXT* context) except *:
    """
    Setup the context for pyproj
    """
    proj_log_func(context, NULL, pyproj_log_function)
                                 ^
------------------------------------------------------------

pyproj/_datadir.pyx:148:33: Cannot assign type 'void (void *, int, const char *) except * nogil' to 'PJ_LOG_FUNCTION'

[snowman2]

https://cython.readthedocs.io/en/latest/src/userguide/migrating_to_cy30.html#exception-values-and-noexcept

[snowman2]

I believe this should work for current versions of pyproj:

python -m pip install 'cython<3'
python -m pip install --no-use-pep517 pyproj

To install the version with the fix implemented:

python -m pip install pyproj@git+https://github.com/pyproj4/pyproj.git@main

[pritish-ranjan01]

Same problem with our docker build.

BASE_IMAGE=python:3.9-alpine3.16
pyproj = "~=2.6.1"

poetry = 1.2.2

Error:-

at /usr/local/lib/python3.9/site-packages/poetry/utils/pip.py:51 in pip_install
47│
48│ try:
49│ return environment.run_pip(*args)
50│ except EnvCommandError as e:
→ 51│ raise PoetryException(f"Failed to install {path.as_posix()}") from e
52│

[snowman2]

Does this work: python-poetry/poetry#3433 (comment)

poetry run python -m pip install 'cython<3'
poetry run python -m pip install --no-use-pep517 pyproj
poetry install

[richieho-chownow]

It does not work for projects that still use setup.py.

ERROR: Disabling PEP 517 processing is invalid: project specifies a build backend of setuptools.build_meta in pyproject.toml

Seems like you have the fix in v3.6.1. If so, when will will it be released?
@snowman2

[snowman2]

Seems like you have the fix in v3.6.1. If so, when will will it be released?

Here is the 3.6.1 milestone: https://github.com/pyproj4/pyproj/milestone/11. With current dependencies, it is expected to arrive sometime at the end of September or beginning of October.

[richieho-chownow]

I see Python 3.12 as a dep. Will projects that use pyproj also need to be on Python 3.12?

[snowman2]

Will projects that use pyproj also need to be on Python 3.12?

Python 3.12 support will be added (i.e. wheels) in addition to currently supported Python versions.

[snowman2]

https://pypi.org/project/pyproj/3.6.1/