Merge branch 'main' into gh-142867-fix-trace-count-missing-lines

Author: heathdutton

Doc/library/base64.rst

@@ -267,14 +267,20 @@ Refer to the documentation of the individual functions for more information.
    .. versionadded:: 3.4
 
 
-.. function:: z85encode(s)
+.. function:: z85encode(s, pad=False)
 
    Encode the :term:`bytes-like object` *s* using Z85 (as used in ZeroMQ)
    and return the encoded :class:`bytes`.  See `Z85  specification
    <https://rfc.zeromq.org/spec/32/>`_ for more information.
 
+   If *pad* is true, the input is padded with ``b'\0'`` so its length is a
+   multiple of 4 bytes before encoding.
+
    .. versionadded:: 3.13
 
+   .. versionchanged:: next
+      The *pad* parameter was added.
+
 
 .. function:: z85decode(s)
 

Lib/base64.py

@@ -508,9 +508,9 @@ def b85decode(b):
 )
 _z85_encode_translation = bytes.maketrans(_b85alphabet, _z85alphabet)
 
-def z85encode(s):
+def z85encode(s, pad=False):
     """Encode bytes-like object b in z85 format and return a bytes object."""
-    return b85encode(s).translate(_z85_encode_translation)
+    return b85encode(s, pad).translate(_z85_encode_translation)
 
 def z85decode(s):
     """Decode the z85-encoded bytes-like object or ASCII string b

Lib/test/test_base64.py

@@ -665,6 +665,7 @@ def test_z85encode(self):
 
         tests = {
             b'': b'',
+            b'\x86\x4F\xD2\x6F\xB5\x59\xF7\x5B': b'HelloWorld',
             b'www.python.org': b'CxXl-AcVLsz/dgCA+t',
             bytes(range(255)): b"""009c61o!#m2NH?C3>iWS5d]J*6CRx17-skh9337x"""
                 b"""ar.{NbQB=+c[cR@eg&FcfFLssg=mfIi5%2YjuU>)kTv.7l}6Nnnj=AD"""
@@ -840,6 +841,21 @@ def test_b85_padding(self):
         eq(base64.b85decode(b'czAet'), b"xxxx")
         eq(base64.b85decode(b'czAetcmMzZ'), b"xxxxx\x00\x00\x00")
 
+    def test_z85_padding(self):
+        eq = self.assertEqual
+
+        eq(base64.z85encode(b"x", pad=True), b'CMmZz')
+        eq(base64.z85encode(b"xx", pad=True), b'CZ6h*')
+        eq(base64.z85encode(b"xxx", pad=True), b'CZaDk')
+        eq(base64.z85encode(b"xxxx", pad=True), b'CZaET')
+        eq(base64.z85encode(b"xxxxx", pad=True), b'CZaETCMmZz')
+
+        eq(base64.z85decode(b'CMmZz'), b"x\x00\x00\x00")
+        eq(base64.z85decode(b'CZ6h*'), b"xx\x00\x00")
+        eq(base64.z85decode(b'CZaDk'), b"xxx\x00")
+        eq(base64.z85decode(b'CZaET'), b"xxxx")
+        eq(base64.z85decode(b'CZaETCMmZz'), b"xxxxx\x00\x00\x00")
+
     def test_a85decode_errors(self):
         illegal = (set(range(32)) | set(range(118, 256))) - set(b' \t\n\r\v')
         for c in illegal:

Lib/test/test_collections.py

@@ -2135,6 +2135,19 @@ def test_basics(self):
         self.assertEqual(c.setdefault('e', 5), 5)
         self.assertEqual(c['e'], 5)
 
+    def test_update_reentrant_add_clears_counter(self):
+        c = Counter()
+        key = object()
+
+        class Evil(int):
+            def __add__(self, other):
+                c.clear()
+                return NotImplemented
+
+        c[key] = Evil()
+        c.update([key])
+        self.assertEqual(c[key], 1)
+
     def test_init(self):
         self.assertEqual(list(Counter(self=42).items()), [('self', 42)])
         self.assertEqual(list(Counter(iterable=42).items()), [('iterable', 42)])

Lib/test/test_ctypes/test_struct_fields.py

@@ -130,6 +130,21 @@ class S(Structure):
             self.check_struct(S)
             self.assertEqual(S.largeField.bit_size, size * 8)
 
+    def test_bitfield_overflow_error_message(self):
+        with self.assertRaisesRegex(
+            ValueError,
+            r"bit field 'x' overflows its type \(2 \+ 7 > 8\)",
+        ):
+            CField(
+                name="x",
+                type=c_byte,
+                byte_size=1,
+                byte_offset=0,
+                index=0,
+                _internal_use=True,
+                bit_size=7,
+                bit_offset=2,
+            )
 
     # __set__ and __get__ should raise a TypeError in case their self
     # argument is not a ctype instance.

Lib/test/test_free_threading/test_gc.py

@@ -62,6 +62,38 @@ def mutator_thread():
         with threading_helper.start_threads(gcs + mutators):
             pass
 
+    def test_freeze_object_in_brc_queue(self):
+        # GH-142975: Freezing objects in the BRC queue could result in some
+        # objects having a zero refcount without being deallocated.
+
+        class Weird:
+            # We need a destructor to trigger the check for object resurrection
+            def __del__(self):
+                pass
+
+        # This is owned by the main thread, so the subthread will have to increment
+        # this object's reference count.
+        weird = Weird()
+
+        def evil():
+            gc.freeze()
+
+            # Decrement the reference count from this thread, which will trigger the
+            # slow path during resurrection and add our weird object to the BRC queue.
+            nonlocal weird
+            del weird
+
+            # Collection will merge the object's reference count and make it zero.
+            gc.collect()
+
+            # Unfreeze the object, making it visible to the GC.
+            gc.unfreeze()
+            gc.collect()
+
+        thread = Thread(target=evil)
+        thread.start()
+        thread.join()
+
 
 if __name__ == "__main__":
     unittest.main()

Misc/ACKS

@@ -418,6 +418,7 @@ Lisandro Dalcin
 Darren Dale
 Andrew Dalke
 Lars Damerow
+Hauke Dämpfling
 Evan Dandrea
 Eric Daniel
 Scott David Daniels

Misc/NEWS.d/next/Core_and_Builtins/2025-12-24-13-44-24.gh-issue-142975.8C4vIP.rst

@@ -0,0 +1,2 @@
+Fix crash after unfreezing all objects tracked by the garbage collector on
+the :term:`free threaded <free threading>` build.

Misc/NEWS.d/next/Library/2025-12-22-00-00-00.gh-issue-143004.uaf-counter.rst

@@ -0,0 +1,2 @@
+Fix a potential use-after-free in :meth:`collections.Counter.update` when user code
+mutates the Counter during an update.

Misc/NEWS.d/next/Library/2025-12-23-17-07-22.gh-issue-143103.LRjXEW.rst

@@ -0,0 +1 @@
+Add padding support to :func:`base64.z85encode` via the ``pad`` parameter.