PyToCType uses internal function removed from Python 3.13

[mkleehammer]

Cannot compile using 3.13:

src/params.cpp: In function ‘int PyToCType(Cursor*, unsigned char**, PyObject*, ParamInfo*)’:
src/params.cpp:250:36: error: too few arguments to function ‘int _PyLong_AsByteArray(PyLongObject*, unsigned char*, size_t, int, int, int)’
  250 |             if (_PyLong_AsByteArray((PyLongObject*)absVal, pNum->val, sizeof(pNum->val), 1, 0))
      |                 ~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

We need to figure out how to bind Decimals without using this, I guess.

[v-chojas]

We're not the only ones affected by this regression: python/cpython#111140
pyodbc is mentioned there along with some other projects.

[AdamWill]

it seems a public function PyLong_AsNativeBytes has been added to do this job, IIUC. See https://github.com/python/cpython/blob/main/Doc/c-api/long.rst for docs on it.

As the error you get - "too few arguments" - implies, the function was re-added after it was removed, but then an extra argument, with_exceptions (an int acting as a boolean), was added in the same commit that introduced PyLong_AsNativeBytes. So for the short term, I think just adding the extra arg to the call would work. For the long term probably a good idea to switch to using the new public function, though. It seems setting with_exceptions to 1 would behave as the function did before (setting it to 0 skips raising an exception when trying to convert a negative int to unsigned).

[AdamWill]

Sent #1361 .