Properly coerce fractions as int (#1757)

Author: Viicos

src/input/input_python.rs

@@ -3,6 +3,7 @@ use std::str::from_utf8;
 use pyo3::intern;
 use pyo3::prelude::*;
 
+use pyo3::sync::GILOnceCell;
 use pyo3::types::PyType;
 use pyo3::types::{
     PyBool, PyByteArray, PyBytes, PyComplex, PyDate, PyDateTime, PyDict, PyFloat, PyFrozenSet, PyInt, PyIterator,
@@ -30,7 +31,8 @@ use super::input_abstract::ValMatch;
 use super::return_enums::EitherComplex;
 use super::return_enums::{iterate_attributes, iterate_mapping_items, ValidationMatch};
 use super::shared::{
-    decimal_as_int, float_as_int, get_enum_meta_object, int_as_bool, str_as_bool, str_as_float, str_as_int,
+    decimal_as_int, float_as_int, fraction_as_int, get_enum_meta_object, int_as_bool, str_as_bool, str_as_float,
+    str_as_int,
 };
 use super::Arguments;
 use super::ConsumeIterator;
@@ -45,6 +47,20 @@ use super::{
     Input,
 };
 
+static FRACTION_TYPE: GILOnceCell<Py<PyType>> = GILOnceCell::new();
+
+pub fn get_fraction_type(py: Python) -> &Bound<'_, PyType> {
+    FRACTION_TYPE
+        .get_or_init(py, || {
+            py.import("fractions")
+                .and_then(|fractions_module| fractions_module.getattr("Fraction"))
+                .unwrap()
+                .extract()
+                .unwrap()
+        })
+        .bind(py)
+}
+
 pub(crate) fn downcast_python_input<'py, T: PyTypeCheck>(input: &(impl Input<'py> + ?Sized)) -> Option<&Bound<'py, T>> {
     input.as_python().and_then(|any| any.downcast::<T>().ok())
 }
@@ -269,6 +285,8 @@ impl<'py> Input<'py> for Bound<'py, PyAny> {
                     float_as_int(self, self.extract::<f64>()?)
                 } else if let Ok(decimal) = self.validate_decimal(true, self.py()) {
                     decimal_as_int(self, &decimal.into_inner())
+                } else if self.is_instance(get_fraction_type(self.py()))? {
+                    fraction_as_int(self)
                 } else if let Ok(float) = self.extract::<f64>() {
                     float_as_int(self, float)
                 } else if let Some(enum_val) = maybe_as_enum(self) {

src/input/shared.rs

@@ -227,3 +227,23 @@ pub fn decimal_as_int<'py>(
     }
     Ok(EitherInt::Py(numerator))
 }
+
+pub fn fraction_as_int<'py>(input: &Bound<'py, PyAny>) -> ValResult<EitherInt<'py>> {
+    #[cfg(Py_3_12)]
+    let is_integer = input.call_method0("is_integer")?.extract::<bool>()?;
+    #[cfg(not(Py_3_12))]
+    let is_integer = input.getattr("denominator")?.extract::<i64>().map_or(false, |d| d == 1);
+
+    if is_integer {
+        #[cfg(Py_3_11)]
+        let as_int = input.call_method0("__int__");
+        #[cfg(not(Py_3_11))]
+        let as_int = input.call_method0("__trunc__");
+        match as_int {
+            Ok(i) => Ok(EitherInt::Py(i.as_any().to_owned())),
+            Err(_) => Err(ValError::new(ErrorTypeDefaults::IntType, input)),
+        }
+    } else {
+        Err(ValError::new(ErrorTypeDefaults::IntFromFloat, input))
+    }
+}

tests/validators/test_int.py

@@ -1,6 +1,7 @@
 import json
 import re
 from decimal import Decimal
+from fractions import Fraction
 from typing import Any
 
 import pytest
@@ -132,13 +133,22 @@ def test_int_py_and_json(py_and_json: PyAndJson, input_value, expected):
         (-i64_max + 1, -i64_max + 1),
         (i64_max * 2, i64_max * 2),
         (-i64_max * 2, -i64_max * 2),
+        (Fraction(10_935_244_710_974_505), 10_935_244_710_974_505),  # https://github.com/pydantic/pydantic/issues/12063
+        pytest.param(
+            Fraction(1, 2),
+            Err(
+                'Input should be a valid integer, got a number with a fractional part '
+                '[type=int_from_float, input_value=Fraction(1, 2), input_type=Fraction]'
+            ),
+            id='fraction-remainder',
+        ),
         pytest.param(
             1.00000000001,
             Err(
                 'Input should be a valid integer, got a number with a fractional part '
                 '[type=int_from_float, input_value=1.00000000001, input_type=float]'
             ),
-            id='decimal-remainder',
+            id='float-remainder',
         ),
         pytest.param(
             Decimal('1.001'),