Fix int rounding

crates/vm/src/builtins/int.rs

@@ -12,7 +12,8 @@ use crate::{
     },
     convert::{IntoPyException, ToPyObject, ToPyResult},
     function::{
-        ArgByteOrder, ArgIntoBool, FuncArgs, OptionalArg, PyArithmeticValue, PyComparisonValue,
+        ArgByteOrder, ArgIntoBool, FuncArgs, OptionalArg, OptionalOption, PyArithmeticValue,
+        PyComparisonValue,
     },
     protocol::{PyNumberMethods, handle_bytes_to_int_err},
     types::{AsNumber, Comparable, Constructor, Hashable, PyComparisonOp, Representable},
@@ -381,10 +382,10 @@ impl PyInt {
     #[pymethod]
     fn __round__(
         zelf: PyRef<Self>,
-        ndigits: OptionalArg<PyIntRef>,
+        ndigits: OptionalOption<PyIntRef>,
         vm: &VirtualMachine,
     ) -> PyResult<PyRef<Self>> {
-        if let OptionalArg::Present(ndigits) = ndigits {
+        if let Some(ndigits) = ndigits.flatten() {
             let ndigits = ndigits.as_bigint();
             // round(12345, -2) == 12300
             // If precision >= 0, then any integer is already rounded correctly

extra_tests/snippets/builtin_int.py

@@ -318,8 +318,9 @@ assert isinstance((0).__round__(0), int)
 assert isinstance((1).__round__(0), int)
 assert (0).__round__(0) == 0
 assert (1).__round__(0) == 1
-assert_raises(TypeError, lambda: (0).__round__(None))
-assert_raises(TypeError, lambda: (1).__round__(None))
+# Python 3.14+: __round__(None) is now allowed, same as __round__()
+assert (0).__round__(None) == 0
+assert (1).__round__(None) == 1
 assert_raises(TypeError, lambda: (0).__round__(0.0))
 assert_raises(TypeError, lambda: (1).__round__(0.0))