Issue #24731: Fixed crash on converting objects with special methods

__bytes__, __trunc__, and __float__ returning instances of subclasses of
bytes, int, and float to subclasses of bytes, int, and float correspondingly.

4 files changed, 40 insertions, 4 deletions

diff --git a/Lib/test/test_bytes.py b/Lib/test/test_bytes.py
index 53a80f4..8158f78 100644
--- a/Lib/test/test_bytes.py
+++ b/Lib/test/test_bytes.py
@@ -779,6 +779,14 @@ class BytesTest(BaseBytesTest, unittest.TestCase):
             def __index__(self):
                 return 42
         self.assertEqual(bytes(A()), b'a')
+        # Issue #24731
+        class A:
+            def __bytes__(self):
+                return OtherBytesSubclass(b'abc')
+        self.assertEqual(bytes(A()), b'abc')
+        self.assertIs(type(bytes(A())), OtherBytesSubclass)
+        self.assertEqual(BytesSubclass(A()), b'abc')
+        self.assertIs(type(BytesSubclass(A())), BytesSubclass)
 
     # Test PyBytes_FromFormat()
     def test_from_format(self):
@@ -1552,6 +1560,9 @@ class ByteArraySubclass(bytearray):
 class BytesSubclass(bytes):
     pass
 
+class OtherBytesSubclass(bytes):
+    pass
+
 class ByteArraySubclassTest(SubclassTest, unittest.TestCase):
     type2test = bytearray
     subclass2test = ByteArraySubclass
diff --git a/Lib/test/test_float.py b/Lib/test/test_float.py
index 723beb3..48f7a70 100644
--- a/Lib/test/test_float.py
+++ b/Lib/test/test_float.py
@@ -25,6 +25,12 @@ requires_setformat = unittest.skipUnless(hasattr(float, "__setformat__"),
 test_dir = os.path.dirname(__file__) or os.curdir
 format_testfile = os.path.join(test_dir, 'formatfloat_testcases.txt')
 
+class FloatSubclass(float):
+    pass
+
+class OtherFloatSubclass(float):
+    pass
+
 class GeneralFloatCases(unittest.TestCase):
 
     def test_float(self):
@@ -167,6 +173,15 @@ class GeneralFloatCases(unittest.TestCase):
                 return ""
         self.assertRaises(TypeError, time.sleep, Foo5())
 
+        # Issue #24731
+        class F:
+            def __float__(self):
+                return OtherFloatSubclass(42.)
+        self.assertAlmostEqual(float(F()), 42.)
+        self.assertIs(type(float(F())), OtherFloatSubclass)
+        self.assertAlmostEqual(FloatSubclass(F()), 42.)
+        self.assertIs(type(FloatSubclass(F())), FloatSubclass)
+
     def test_is_integer(self):
         self.assertFalse((1.1).is_integer())
         self.assertTrue((1.).is_integer())
diff --git a/Lib/test/test_int.py b/Lib/test/test_int.py
index 3e4b4fc..b66c5d6 100644
--- a/Lib/test/test_int.py
+++ b/Lib/test/test_int.py
@@ -24,6 +24,9 @@ L = [
         ("\u0200", ValueError)
 ]
 
+class IntSubclass(int):
+    pass
+
 class IntTestCases(unittest.TestCase):
 
     def test_basic(self):
@@ -441,6 +444,10 @@ class IntTestCases(unittest.TestCase):
         good_int = TruncReturnsIntSubclass()
         n = int(good_int)
         self.assertEqual(n, 1)
+        self.assertIs(type(n), bool)
+        n = IntSubclass(good_int)
+        self.assertEqual(n, 1)
+        self.assertIs(type(n), IntSubclass)
 
     def test_error_message(self):
         def check(s, base=None):
diff --git a/Lib/test/test_unicode.py b/Lib/test/test_unicode.py
index 56a60df..ce8df40 100644
--- a/Lib/test/test_unicode.py
+++ b/Lib/test/test_unicode.py
@@ -43,6 +43,9 @@ def duplicate_string(text):
     """
     return text.encode().decode()
 
+class StrSubclass(str):
+    pass
+
 class UnicodeTest(string_tests.CommonTest,
         string_tests.MixinStrUnicodeUserStringTest,
         string_tests.MixinStrUnicodeTest,
@@ -1441,11 +1444,8 @@ class UnicodeTest(string_tests.CommonTest,
             'unicode remains unicode'
         )
 
-        class UnicodeSubclass(str):
-            pass
-
         for text in ('ascii', '\xe9', '\u20ac', '\U0010FFFF'):
-            subclass = UnicodeSubclass(text)
+            subclass = StrSubclass(text)
             self.assertEqual(str(subclass), text)
             self.assertEqual(len(subclass), len(text))
             if text == 'ascii':
@@ -2199,6 +2199,9 @@ class UnicodeTest(string_tests.CommonTest,
         s = str(StrSubclassToStrSubclass("foo"))
         self.assertEqual(s, "foofoo")
         self.assertIs(type(s), StrSubclassToStrSubclass)
+        s = StrSubclass(StrSubclassToStrSubclass("foo"))
+        self.assertEqual(s, "foofoo")
+        self.assertIs(type(s), StrSubclass)
 
     def test_unicode_repr(self):
         class s1: