test_functools.py 文件源码

def test_need_for_rlock(self):
        # This will deadlock on an LRU cache that uses a regular lock

        @functools.lru_cache(maxsize=10)
        def test_func(x):
            'Used to demonstrate a reentrant lru_cache call within a single thread'
            return x

        class DoubleEq:
            'Demonstrate a reentrant lru_cache call within a single thread'
            def __init__(self, x):
                self.x = x
            def __hash__(self):
                return self.x
            def __eq__(self, other):
                if self.x == 2:
                    test_func(DoubleEq(1))
                return self.x == other.x

        test_func(DoubleEq(1))                      # Load the cache
        test_func(DoubleEq(2))                      # Load the cache
        self.assertEqual(test_func(DoubleEq(2)),    # Trigger a re-entrant __eq__ call
                         DoubleEq(2))               # Verify the correct return value