Different behavior with mock to same class or different class

Bug report

Bug description:

import unittest
from unittest.mock import patch

class Number:
    def __init__(self, value):
        print(f'init: {value}')
        self.value = value

    def get_value(self):
        return self.value

class MockNumber:
    def __init__(self, value):
        print(f'mock init: {value}')
        self.value = value

    def get_value(self):
        return self.value

class TestNumber(unittest.TestCase):
    def setUp(self):
        pass

    def tearDown(self):
        pass

    def test_number(self):
        number = Number(1)
        with patch.object(Number, '__new__', return_value=number):
            test = Number(2)
            print(test.get_value())

        mock_number = MockNumber(1)
        with patch.object(Number, '__new__', return_value=mock_number):
            test = Number(2)
            print(test.get_value())

if __name__ == '__main__':
    unittest.main()

The output is

init: 1
init: 2
2
mock init: 1
1
.
----------------------------------------------------------------------
Ran 1 test in 0.001s

OK

When mock the function new of class Number to return an instance of MockNumber, the behavior is simple: just return the instance of MockNumber.
But when mock the function to return an instance of Number, the function of init will still be called.

CPython versions tested on:

3.11

Operating systems tested on:

Linux

提供されたunittestから始め、Numberを返す場合とMockNumberを返す場合のpatch.object(Number, 'new')を比較します。__new__と__init__周辺のPythonのオブジェクト構築動作を追跡し、その違いが意図されたものかどうかを判断します。完了条件は、動作が確認され、適切なリグレッションカバレッジまたはドキュメントが用意されていることです。