Is the shortcircuit behaviour of Python's any/all explicit?

Question

Prompted by the discussion here

The docs suggest some equivalent code for the behaviour of all and any

Should the behaviour of the equivalent code be considered part of the definition, or can an implementation implement them in a non-shortcircuit manner?

Here is the relevant excerpt from cpython/Lib/test/test_builtin.py

def test_all(self):     self.assertEqual(all([2, 4, 6]), True)     self.assertEqual(all([2, None, 6]), False)     self.assertRaises(RuntimeError, all, [2, TestFailingBool(), 6])     self.assertRaises(RuntimeError, all, TestFailingIter())     self.assertRaises(TypeError, all, 10)               # Non-iterable     self.assertRaises(TypeError, all)                   # No args     self.assertRaises(TypeError, all, [2, 4, 6], [])    # Too many args     self.assertEqual(all([]), True)                     # Empty iterator     S = [50, 60]     self.assertEqual(all(x > 42 for x in S), True)     S = [50, 40, 60]     self.assertEqual(all(x > 42 for x in S), False)  def test_any(self):     self.assertEqual(any([None, None, None]), False)     self.assertEqual(any([None, 4, None]), True)     self.assertRaises(RuntimeError, any, [None, TestFailingBool(), 6])     self.assertRaises(RuntimeError, all, TestFailingIter())     self.assertRaises(TypeError, any, 10)               # Non-iterable     self.assertRaises(TypeError, any)                   # No args     self.assertRaises(TypeError, any, [2, 4, 6], [])    # Too many args     self.assertEqual(any([]), False)                    # Empty iterator     S = [40, 60, 30]     self.assertEqual(any(x > 42 for x in S), True)     S = [10, 20, 30]     self.assertEqual(any(x > 42 for x in S), False) 

It doesn't do anything to enforce the shortcircuit behaviour

Answer 1

The behaviour is guaranteed. I've contributed a patch, which was accepted and merged recently, so if you grab the latest sources you will see that the short-circuiting behaviour is now explicitly enforced.

git clone https://github.com/python/cpython.git grep Short-circuit cpython/Lib/test/test_builtin.py