pyodbc fails to build with Python 3.12.0a3.

src/pyodbccompat.h: In function ‘PyObject* Text_New(Py_ssize_t)’:
src/pyodbccompat.h:75:12: error: ‘PyUnicode_FromUnicode’ was not declared in this scope; did you mean ‘PyUnicode_FromString’?
   75 |     return PyUnicode_FromUnicode(0, length);
      |            ^~~~~~~~~~~~~~~~~~~~~
      |            PyUnicode_FromString
src/pyodbccompat.h: In function ‘Py_UNICODE* Text_Buffer(PyObject*)’:
src/pyodbccompat.h:86:12: error: ‘PyUnicode_AS_UNICODE’ was not declared in this scope; did you mean ‘PyUnicode_AsUCS4’?
   86 |     return PyUnicode_AS_UNICODE(o);
      |            ^~~~~~~~~~~~~~~~~~~~
      |            PyUnicode_AsUCS4
src/pyodbccompat.h: In function ‘Py_ssize_t Text_Size(PyObject*)’:
src/pyodbccompat.h:126:40: error: ‘PyUnicode_GET_SIZE’ was not declared in this scope; did you mean ‘PyDict_GET_SIZE’?
  126 |     return (o && PyUnicode_Check(o)) ? PyUnicode_GET_SIZE(o) : 0;
      |                                        ^~~~~~~~~~~~~~~~~~
      |                                        PyDict_GET_SIZE
src/pyodbccompat.h: In function ‘Py_ssize_t TextCopyToUnicode(Py_UNICODE*, PyObject*)’:
src/pyodbccompat.h:146:26: error: ‘PyUnicode_GET_SIZE’ was not declared in this scope; did you mean ‘PyDict_GET_SIZE’?
  146 |         Py_ssize_t cch = PyUnicode_GET_SIZE(o);
      |                          ^~~~~~~~~~~~~~~~~~
      |                          PyDict_GET_SIZE
src/pyodbccompat.h:147:24: error: ‘PyUnicode_AS_UNICODE’ was not declared in this scope; did you mean ‘PyUnicode_AsUCS4’?
  147 |         memcpy(buffer, PyUnicode_AS_UNICODE(o), cch * sizeof(Py_UNICODE));
      |                        ^~~~~~~~~~~~~~~~~~~~
      |                        PyUnicode_AsUCS4

Leagcy Unicode APIs has been removed. See PEP 623 for detail.
        PyUnicode_WCHAR_KIND
        PyUnicode_AS_UNICODE()
        PyUnicode_AsUnicode()
        PyUnicode_AsUnicodeAndSize()
        PyUnicode_AS_DATA()
        PyUnicode_FromUnicode()
        PyUnicode_GET_SIZE()
        PyUnicode_GetSize()
        PyUnicode_GET_DATA_SIZE()

https://docs.python.org/3.12/whatsnew/3.12.html

For the build logs, see:
https://copr-be.cloud.fedoraproject.org/results/@python/python3.12/fedora-rawhide-x86_64/05129554-pyodbc/

For all our attempts to build pyodbc with Python 3.12, see:
https://copr.fedorainfracloud.org/coprs/g/python/python3.12/package/pyodbc/

Testing and mass rebuild of packages is happening in copr. You can follow these instructions to test locally in mock if your package builds with Python 3.12:
https://copr.fedorainfracloud.org/coprs/g/python/python3.12/

Let us know here if you have any questions.

Python 3.12 is planned to be included in Fedora 39. To make that update smoother, we're building Fedora packages with all pre-releases of Python 3.12.
A build failure prevents us from testing all dependent packages (transitive [Build]Requires), so if this package is required a lot, it's important for us to get it fixed soon.
We'd appreciate help from the people who know this package best, but if you don't want to work on this now, let us know so we can try to work around it on our side.