Describe the bug

common.pxd:

cdef enum:
    NPY_MAXDIMS = 32

This constant can be imported from Cython-only modules to create arrays in the stack:

demo.pyx:

from mypackage.common cimport NPY_MAXDIMS

def f():
    cdef int[NPY_MAXDIMS] scratch

However, the same crashes in Pure-python mode:
demo2.py:

import cython
if cython.compiled:
    from cython.cimports.mypackage.common import NPY_MAXDIMS
else:
    NPY_MAXDIMS = 32

def f():
    scratch: cython.int[NPY_MAXDIMS]
    if not cython.compiled:
        scratch = [None] * NPY_MAXDIMS

The latter crashes during compilation:

mypackage.demo2.py:6:41: Array size must be a compile time constant

I could not find any other way to define the size of the scratch buffer in pure-python mode other than hardcoding it. This works but it's very poorly maintainable:

import cython

def f():
    scratch: cython.int[32]
    if not cython.compiled:
        scratch = [None] * 32

Python version

3.12.7

Cython version

3.0.11