Added test for issue 135241

Author: Legoclones

Lib/test/test_pickle.py

@@ -376,6 +376,16 @@ class CUnpicklerTests(PyUnpicklerTests):
         bad_stack_errors = (pickle.UnpicklingError,)
         truncated_errors = (pickle.UnpicklingError,)
 
+        def test_issue135241(self):
+            # C implementation should check for hardcoded values 00 and 01
+            # when getting booleans from the INT opcode. Doing a str comparison
+            # to bypass truthy/falsy comparisons. These payloads should return
+            # 0, not False.
+            out1 = self.loads(b'I+0\n.')
+            self.assertTrue(str(out1) == str(0))
+            out2 = self.loads(b'I 0\n.')
+            self.assertTrue(str(out2) == str(0))
+
     class CPicklingErrorTests(PyPicklingErrorTests):
         pickler = _pickle.Pickler
 

Misc/NEWS.d/next/Library/2025-06-08-01-10-34.gh-issue-135241.5j18IW.rst

@@ -1 +1 @@
-The :code:`INT` opcode of the C accelerator :mod:`_pickle` module was updated to look only for "00" and "01" to push booleans onto the stack, aligning with the Python :mod:`pickle` module.
+The :code:`INT` opcode of the C accelerator `_pickle` module was updated to look only for "00" and "01" to push booleans onto the stack, aligning with the Python :mod:`pickle` module.