[BUG] PythonObject doesn't handle large UInt64 correctly

[soraros]

Bug description

As title.

A Mojo UInt64 value went through the following to reach Python runtime:

• PythonObject.__init__[dt: DType](Self, SIMD[dt, 1])
  

  mojo/stdlib/src/python/python_object.mojo

  Lines 294 to 296 in 61d8208

  	elif dt.is_integral():
  	var int_val = value.cast[DType.index]().value
  	self.py_object = cpython.toPython(int_val)

• CPython.toPython(Self, Int)
  

  mojo/stdlib/src/python/_cpython.mojo

  Lines 966 to 967 in 61d8208

  	fn toPython(inout self, litInt: Int) -> PyObjectPtr:
  	return self.PyLong_FromLong(litInt.value)

• CPython.PyLong_FromLong(Self, Int)
  

  mojo/stdlib/src/python/_cpython.mojo

  Lines 889 to 902 in 61d8208

  	fn PyLong_FromLong(inout self, value: Int) -> PyObjectPtr:
  	var r = self.lib.get_function[fn (Int) -> PyObjectPtr](
  	"PyLong_FromLong"
  	)(value)
  	if self.logging_enabled:
  	print(
  	r._get_ptr_as_int(),
  	" NEWREF PyLong_FromLong, refcnt:",
  	self._Py_REFCNT(r),
  	", value:",
  	value,
  	)
  	self._inc_total_rc()
  	return r

• PyLong_FromLong with signature PyObject *PyLong_FromLong(long v)

An unwanted bit cast happened on CPython's API boundary.

We should

• Add a branch in PythonObject.__init__
• Add a method calling PyLong_FromUnsignedLong on struct CPython
• Wire them up

Steps to reproduce

from python import PythonObject

def main():
  n = UInt64(0xFEDCBA0987654321)
  print(PythonObject(n))  # prints -81986143110479071

A more peculiar repro:

from python import Python

def main():
  py = Python.import_module("builtins")
  a = UInt64(0x1234567890ABCDEF)
  b = UInt64(0xFEDCBA0987654321)
  # bb = py.int(str(b))      # doesn't crash
  a, bb = a, py.int(str(b))  # only crashes when tuple unpacking is used
  print(a + bb)

System information

Mojo 2024.9.905 (ae516e17) on Docker, Intel Mac

[dhruvmalik007]

hi @JoeLoser , here is the code that will act patch for this bug : dhruvmalik007@bf8d434 , let me know if you need more tests / changes required and I will do the needful in order to create PR and merge .

Thanks

[soraros]

Hi @dhruvmalik007, thanks for your interest! Feel free to make a PR and we can iterate there.