fix len() when __len__() returns a non number type #5137
diff --git a/Lib/test/test_builtin.py b/Lib/test/test_builtin.py
index 0aa0d52..a62e124 100644
--- a/Lib/test/test_builtin.py
+++ b/Lib/test/test_builtin.py
@@ -611,6 +611,18 @@
def __len__(self):
raise ValueError
self.assertRaises(ValueError, len, BadSeq())
+ class InvalidLen:
+ def __len__(self):
+ return None
+ self.assertRaises(TypeError, len, InvalidLen())
+ class FloatLen:
+ def __len__(self):
+ return 4.5
+ self.assertRaises(TypeError, len, FloatLen())
+ class HugeLen:
+ def __len__(self):
+ return sys.maxsize + 1
+ self.assertRaises(OverflowError, len, HugeLen())
def test_map(self):
self.assertEqual(
diff --git a/Misc/NEWS b/Misc/NEWS
index a0a8d1f..5a3b4ad 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -12,6 +12,9 @@
Core and Builtins
-----------------
+- Issue #5137: Make len() correctly raise a TypeError when a __len__ method
+ returns a non-number type.
+
- Issue #5182: Removed memoryview.__str__.
- Issue #1717: Removed builtin cmp() function, dropped tp_compare
diff --git a/Objects/typeobject.c b/Objects/typeobject.c
index 47e425c..a362b84 100644
--- a/Objects/typeobject.c
+++ b/Objects/typeobject.c
@@ -4618,7 +4618,7 @@
if (res == NULL)
return -1;
- len = PyLong_AsSsize_t(res);
+ len = PyNumber_AsSsize_t(res, PyExc_OverflowError);
Py_DECREF(res);
if (len < 0) {
if (!PyErr_Occurred())