Issue #17576: Deprecation warning emitted now when __int__() or __index__()

return not int instance.  Introduced _PyLong_FromNbInt() and refactored
PyLong_As*() functions.

Author: serhiy-storchaka

Include/longobject.h

@@ -152,6 +152,12 @@ PyAPI_FUNC(int) _PyLong_AsByteArray(PyLongObject* v,
     unsigned char* bytes, size_t n,
     int little_endian, int is_signed);
 
+/* _PyLong_FromNbInt: Convert the given object to a PyLongObject
+   using the nb_int slot, if available.  Raise TypeError if either the
+   nb_int slot is not available or the result of the call to nb_int
+   returns something not of type int.
+*/
+PyAPI_FUNC(PyLongObject *)_PyLong_FromNbInt(PyObject *);
 
 /* _PyLong_Format: Convert the long to a string object with given base,
    appending a base prefix of 0[box] if base is 2, 8 or 16. */

Lib/test/test_getargs2.py

@@ -50,12 +50,34 @@ class Int:
     def __int__(self):
         return 99
 
+class IntSubclass(int):
+    def __int__(self):
+        return 99
+
+class BadInt:
+    def __int__(self):
+        return 1.0
+
+class BadInt2:
+    def __int__(self):
+        return True
+
+class BadInt3(int):
+    def __int__(self):
+        return True
+
+
 class Unsigned_TestCase(unittest.TestCase):
     def test_b(self):
         from _testcapi import getargs_b
         # b returns 'unsigned char', and does range checking (0 ... UCHAR_MAX)
         self.assertRaises(TypeError, getargs_b, 3.14)
         self.assertEqual(99, getargs_b(Int()))
+        self.assertEqual(0, getargs_b(IntSubclass()))
+        self.assertRaises(TypeError, getargs_b, BadInt())
+        with self.assertWarns(DeprecationWarning):
+            self.assertEqual(1, getargs_b(BadInt2()))
+        self.assertEqual(0, getargs_b(BadInt3()))
 
         self.assertRaises(OverflowError, getargs_b, -1)
         self.assertEqual(0, getargs_b(0))
@@ -70,6 +92,11 @@ def test_B(self):
         # B returns 'unsigned char', no range checking
         self.assertRaises(TypeError, getargs_B, 3.14)
         self.assertEqual(99, getargs_B(Int()))
+        self.assertEqual(0, getargs_B(IntSubclass()))
+        self.assertRaises(TypeError, getargs_B, BadInt())
+        with self.assertWarns(DeprecationWarning):
+            self.assertEqual(1, getargs_B(BadInt2()))
+        self.assertEqual(0, getargs_B(BadInt3()))
 
         self.assertEqual(UCHAR_MAX, getargs_B(-1))
         self.assertEqual(0, getargs_B(0))
@@ -84,6 +111,11 @@ def test_H(self):
         # H returns 'unsigned short', no range checking
         self.assertRaises(TypeError, getargs_H, 3.14)
         self.assertEqual(99, getargs_H(Int()))
+        self.assertEqual(0, getargs_H(IntSubclass()))
+        self.assertRaises(TypeError, getargs_H, BadInt())
+        with self.assertWarns(DeprecationWarning):
+            self.assertEqual(1, getargs_H(BadInt2()))
+        self.assertEqual(0, getargs_H(BadInt3()))
 
         self.assertEqual(USHRT_MAX, getargs_H(-1))
         self.assertEqual(0, getargs_H(0))
@@ -99,6 +131,11 @@ def test_I(self):
         # I returns 'unsigned int', no range checking
         self.assertRaises(TypeError, getargs_I, 3.14)
         self.assertEqual(99, getargs_I(Int()))
+        self.assertEqual(0, getargs_I(IntSubclass()))
+        self.assertRaises(TypeError, getargs_I, BadInt())
+        with self.assertWarns(DeprecationWarning):
+            self.assertEqual(1, getargs_I(BadInt2()))
+        self.assertEqual(0, getargs_I(BadInt3()))
 
         self.assertEqual(UINT_MAX, getargs_I(-1))
         self.assertEqual(0, getargs_I(0))
@@ -115,6 +152,10 @@ def test_k(self):
         # it does not accept float, or instances with __int__
         self.assertRaises(TypeError, getargs_k, 3.14)
         self.assertRaises(TypeError, getargs_k, Int())
+        self.assertEqual(0, getargs_k(IntSubclass()))
+        self.assertRaises(TypeError, getargs_k, BadInt())
+        self.assertRaises(TypeError, getargs_k, BadInt2())
+        self.assertEqual(0, getargs_k(BadInt3()))
 
         self.assertEqual(ULONG_MAX, getargs_k(-1))
         self.assertEqual(0, getargs_k(0))
@@ -131,6 +172,11 @@ def test_h(self):
         # h returns 'short', and does range checking (SHRT_MIN ... SHRT_MAX)
         self.assertRaises(TypeError, getargs_h, 3.14)
         self.assertEqual(99, getargs_h(Int()))
+        self.assertEqual(0, getargs_h(IntSubclass()))
+        self.assertRaises(TypeError, getargs_h, BadInt())
+        with self.assertWarns(DeprecationWarning):
+            self.assertEqual(1, getargs_h(BadInt2()))
+        self.assertEqual(0, getargs_h(BadInt3()))
 
         self.assertRaises(OverflowError, getargs_h, SHRT_MIN-1)
         self.assertEqual(SHRT_MIN, getargs_h(SHRT_MIN))
@@ -145,6 +191,11 @@ def test_i(self):
         # i returns 'int', and does range checking (INT_MIN ... INT_MAX)
         self.assertRaises(TypeError, getargs_i, 3.14)
         self.assertEqual(99, getargs_i(Int()))
+        self.assertEqual(0, getargs_i(IntSubclass()))
+        self.assertRaises(TypeError, getargs_i, BadInt())
+        with self.assertWarns(DeprecationWarning):
+            self.assertEqual(1, getargs_i(BadInt2()))
+        self.assertEqual(0, getargs_i(BadInt3()))
 
         self.assertRaises(OverflowError, getargs_i, INT_MIN-1)
         self.assertEqual(INT_MIN, getargs_i(INT_MIN))
@@ -159,6 +210,11 @@ def test_l(self):
         # l returns 'long', and does range checking (LONG_MIN ... LONG_MAX)
         self.assertRaises(TypeError, getargs_l, 3.14)
         self.assertEqual(99, getargs_l(Int()))
+        self.assertEqual(0, getargs_l(IntSubclass()))
+        self.assertRaises(TypeError, getargs_l, BadInt())
+        with self.assertWarns(DeprecationWarning):
+            self.assertEqual(1, getargs_l(BadInt2()))
+        self.assertEqual(0, getargs_l(BadInt3()))
 
         self.assertRaises(OverflowError, getargs_l, LONG_MIN-1)
         self.assertEqual(LONG_MIN, getargs_l(LONG_MIN))
@@ -174,6 +230,10 @@ def test_n(self):
         # (PY_SSIZE_T_MIN ... PY_SSIZE_T_MAX)
         self.assertRaises(TypeError, getargs_n, 3.14)
         self.assertRaises(TypeError, getargs_n, Int())
+        self.assertEqual(0, getargs_n(IntSubclass()))
+        self.assertRaises(TypeError, getargs_n, BadInt())
+        self.assertRaises(TypeError, getargs_n, BadInt2())
+        self.assertEqual(0, getargs_n(BadInt3()))
 
         self.assertRaises(OverflowError, getargs_n, PY_SSIZE_T_MIN-1)
         self.assertEqual(PY_SSIZE_T_MIN, getargs_n(PY_SSIZE_T_MIN))
@@ -192,6 +252,11 @@ def test_L(self):
         self.assertRaises(TypeError, getargs_L, 3.14)
         self.assertRaises(TypeError, getargs_L, "Hello")
         self.assertEqual(99, getargs_L(Int()))
+        self.assertEqual(0, getargs_L(IntSubclass()))
+        self.assertRaises(TypeError, getargs_L, BadInt())
+        with self.assertWarns(DeprecationWarning):
+            self.assertEqual(1, getargs_L(BadInt2()))
+        self.assertEqual(0, getargs_L(BadInt3()))
 
         self.assertRaises(OverflowError, getargs_L, LLONG_MIN-1)
         self.assertEqual(LLONG_MIN, getargs_L(LLONG_MIN))
@@ -206,6 +271,11 @@ def test_K(self):
         # K return 'unsigned long long', no range checking
         self.assertRaises(TypeError, getargs_K, 3.14)
         self.assertRaises(TypeError, getargs_K, Int())
+        self.assertEqual(0, getargs_K(IntSubclass()))
+        self.assertRaises(TypeError, getargs_K, BadInt())
+        self.assertRaises(TypeError, getargs_K, BadInt2())
+        self.assertEqual(0, getargs_K(BadInt3()))
+
         self.assertEqual(ULLONG_MAX, getargs_K(ULLONG_MAX))
         self.assertEqual(0, getargs_K(0))
         self.assertEqual(0, getargs_K(ULLONG_MAX+1))

Lib/test/test_index.py

@@ -9,7 +9,7 @@ def __index__(self):
 
 class TrapInt(int):
     def __index__(self):
-        return self
+        return int(self)
 
 class BaseTestCase(unittest.TestCase):
     def setUp(self):
@@ -55,6 +55,40 @@ def test_error(self):
         self.assertRaises(TypeError, slice(self.o).indices, 0)
         self.assertRaises(TypeError, slice(self.n).indices, 0)
 
+    def test_int_subclass_with_index(self):
+        # __index__ should be used when computing indices, even for int
+        # subclasses.  See issue #17576.
+        class MyInt(int):
+            def __index__(self):
+                return int(self) + 1
+
+        my_int = MyInt(7)
+        direct_index = my_int.__index__()
+        operator_index = operator.index(my_int)
+        self.assertEqual(direct_index, 8)
+        self.assertEqual(operator_index, 7)
+        # Both results should be of exact type int.
+        self.assertIs(type(direct_index), int)
+        #self.assertIs(type(operator_index), int)
+
+    def test_index_returns_int_subclass(self):
+        class BadInt:
+            def __index__(self):
+                return True
+
+        class BadInt2(int):
+            def __index__(self):
+                return True
+
+        bad_int = BadInt()
+        with self.assertWarns(DeprecationWarning):
+            n = operator.index(bad_int)
+        self.assertEqual(n, 1)
+
+        bad_int = BadInt2()
+        n = operator.index(bad_int)
+        self.assertEqual(n, 0)
+
 
 class SeqTestCase:
     # This test case isn't run directly. It just defines common tests

Lib/test/test_int.py

@@ -263,32 +263,7 @@ class Foo0:
             def __int__(self):
                 return 42
 
-        class Foo1(object):
-            def __int__(self):
-                return 42
-
-        class Foo2(int):
-            def __int__(self):
-                return 42
-
-        class Foo3(int):
-            def __int__(self):
-                return self
-
-        class Foo4(int):
-            def __int__(self):
-                return 42
-
-        class Foo5(int):
-            def __int__(self):
-                return 42.
-
         self.assertEqual(int(Foo0()), 42)
-        self.assertEqual(int(Foo1()), 42)
-        self.assertEqual(int(Foo2()), 42)
-        self.assertEqual(int(Foo3()), 0)
-        self.assertEqual(int(Foo4()), 42)
-        self.assertRaises(TypeError, int, Foo5())
 
         class Classic:
             pass
@@ -351,6 +326,57 @@ def __trunc__(self):
                 with self.assertRaises(TypeError):
                     int(TruncReturnsBadInt())
 
+    def test_int_subclass_with_int(self):
+        class MyInt(int):
+            def __int__(self):
+                return 42
+
+        class BadInt(int):
+            def __int__(self):
+                return 42.0
+
+        my_int = MyInt(7)
+        self.assertEqual(my_int, 7)
+        self.assertEqual(int(my_int), 42)
+
+        self.assertRaises(TypeError, int, BadInt())
+
+    def test_int_returns_int_subclass(self):
+        class BadInt:
+            def __int__(self):
+                return True
+
+        class BadInt2(int):
+            def __int__(self):
+                return True
+
+        class TruncReturnsBadInt:
+            def __trunc__(self):
+                return BadInt()
+
+        class TruncReturnsIntSubclass:
+            def __trunc__(self):
+                return True
+
+        bad_int = BadInt()
+        with self.assertWarns(DeprecationWarning):
+            n = int(bad_int)
+        self.assertEqual(n, 1)
+
+        bad_int = BadInt2()
+        with self.assertWarns(DeprecationWarning):
+            n = int(bad_int)
+        self.assertEqual(n, 1)
+
+        bad_int = TruncReturnsBadInt()
+        with self.assertWarns(DeprecationWarning):
+            n = int(bad_int)
+        self.assertEqual(n, 1)
+
+        good_int = TruncReturnsIntSubclass()
+        n = int(good_int)
+        self.assertEqual(n, 1)
+
     def test_error_message(self):
         def check(s, base=None):
             with self.assertRaises(ValueError,

Misc/NEWS

@@ -10,6 +10,9 @@ What's New in Python 3.3.4 release candidate 1?
 Core and Builtins
 -----------------
 
+- Issue #17576: Deprecation warning emitted now when __int__() or __index__()
+  return not int instance.
+
 - Issue #19932: Fix typo in import.h, missing whitespaces in function prototypes.
 
 - Issue #19729: In str.format(), fix recursive expansion in format spec.