[pull] main from python:main

.gitignore

@@ -124,10 +124,14 @@ PCbuild/*-pgo
 PCbuild/*.VC.db
 PCbuild/*.VC.opendb
 PCbuild/amd64/
+PCbuild/amd64t/
 PCbuild/arm32/
+PCbuild/arm32t/
 PCbuild/arm64/
+PCbuild/arm64t/
 PCbuild/obj/
 PCbuild/win32/
+PCbuild/win32t/
 Tools/unicode/data/
 /autom4te.cache
 /build/

Doc/library/ctypes.rst

@@ -1866,6 +1866,10 @@ like ``find_library("c")`` will fail and return ``None``.
 
    .. availability:: Windows
 
+   .. soft-deprecated:: 3.16
+      This function now always returns ``None``, as there are no more
+      VC runtime DLLs that are a single file and supported by Microsoft.
+
 
 .. _ctypes-listing-loaded-shared-libraries:
 

Doc/license.rst

@@ -1216,3 +1216,52 @@ license::
   LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
   DAMAGE.
+
+
+Unicode Character Database
+--------------------------
+
+An extract of the `Unicode Character Database <https://www.unicode.org/ucd/>`__,
+converted to an internal format, is used by the :mod:`unicodedata` module and
+for the Unicode support of the :class:`str` type. The original Unicode data
+files are distributed under the `Unicode License <https://www.unicode.org/license.txt>`__::
+
+  UNICODE LICENSE V3
+
+  COPYRIGHT AND PERMISSION NOTICE
+
+  Copyright © 1991-2026 Unicode, Inc.
+
+  NOTICE TO USER: Carefully read the following legal agreement. BY
+  DOWNLOADING, INSTALLING, COPYING OR OTHERWISE USING DATA FILES, AND/OR
+  SOFTWARE, YOU UNEQUIVOCALLY ACCEPT, AND AGREE TO BE BOUND BY, ALL OF THE
+  TERMS AND CONDITIONS OF THIS AGREEMENT. IF YOU DO NOT AGREE, DO NOT
+  DOWNLOAD, INSTALL, COPY, DISTRIBUTE OR USE THE DATA FILES OR SOFTWARE.
+
+  Permission is hereby granted, free of charge, to any person obtaining a
+  copy of data files and any associated documentation (the "Data Files") or
+  software and any associated documentation (the "Software") to deal in the
+  Data Files or Software without restriction, including without limitation
+  the rights to use, copy, modify, merge, publish, distribute, and/or sell
+  copies of the Data Files or Software, and to permit persons to whom the
+  Data Files or Software are furnished to do so, provided that either (a)
+  this copyright and permission notice appear with all copies of the Data
+  Files or Software, or (b) this copyright and permission notice appear in
+  associated Documentation.
+
+  THE DATA FILES AND SOFTWARE ARE PROVIDED "AS IS", WITHOUT WARRANTY OF ANY
+  KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+  MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT OF
+  THIRD PARTY RIGHTS.
+
+  IN NO EVENT SHALL THE COPYRIGHT HOLDER OR HOLDERS INCLUDED IN THIS NOTICE
+  BE LIABLE FOR ANY CLAIM, OR ANY SPECIAL INDIRECT OR CONSEQUENTIAL DAMAGES,
+  OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS,
+  WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION,
+  ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THE DATA
+  FILES OR SOFTWARE.
+
+  Except as contained in this notice, the name of a copyright holder shall
+  not be used in advertising or otherwise to promote the sale, use or other
+  dealings in these Data Files or Software without prior written
+  authorization of the copyright holder.

Lib/asyncio/protocols.py

@@ -199,18 +199,19 @@ def process_exited(self):
 
 def _feed_data_to_buffered_proto(proto, data):
     data_len = len(data)
+    start = 0
     while data_len:
         buf = proto.get_buffer(data_len)
         buf_len = len(buf)
         if not buf_len:
             raise RuntimeError('get_buffer() returned an empty buffer')
 
         if buf_len >= data_len:
-            buf[:data_len] = data
+            buf[:data_len] = data[start:] if start else data
             proto.buffer_updated(data_len)
             return
         else:
-            buf[:buf_len] = data[:buf_len]
+            buf[:buf_len] = data[start:start + buf_len]
             proto.buffer_updated(buf_len)
-            data = data[buf_len:]
-            data_len = len(data)
+            start += buf_len
+            data_len -= buf_len

Lib/ctypes/util.py

@@ -13,56 +13,19 @@
 
 # find_library(name) returns the pathname of a library, or None.
 if os.name == "nt":
-
-    def _get_build_version():
-        """Return the version of MSVC that was used to build Python.
-
-        For Python 2.3 and up, the version number is included in
-        sys.version.  For earlier versions, assume the compiler is MSVC 6.
-        """
-        # This function was copied from Lib/distutils/msvccompiler.py
-        prefix = "MSC v."
-        i = sys.version.find(prefix)
-        if i == -1:
-            return 6
-        i = i + len(prefix)
-        s, rest = sys.version[i:].split(" ", 1)
-        majorVersion = int(s[:-2]) - 6
-        if majorVersion >= 13:
-            majorVersion += 1
-        minorVersion = int(s[2:3]) / 10.0
-        # I don't think paths are affected by minor version in version 6
-        if majorVersion == 6:
-            minorVersion = 0
-        if majorVersion >= 6:
-            return majorVersion + minorVersion
-        # else we don't know what version of the compiler this is
-        return None
-
     def find_msvcrt():
-        """Return the name of the VC runtime dll"""
-        version = _get_build_version()
-        if version is None:
-            # better be safe than sorry
-            return None
-        if version <= 6:
-            clibname = 'msvcrt'
-        elif version <= 13:
-            clibname = 'msvcr%d' % (version * 10)
-        else:
-            # CRT is no longer directly loadable. See issue23606 for the
-            # discussion about alternative approaches.
-            return None
-
-        # If python was built with in debug mode
-        import importlib.machinery
-        if '_d.pyd' in importlib.machinery.EXTENSION_SUFFIXES:
-            clibname += 'd'
-        return clibname+'.dll'
+        """Return the name of the VC runtime dll.
+           This is soft deprecated as of Python 3.16."""
+        # See gh-154199. In short, this function wasn't able to return
+        # newer msvcrt versions (because there was no single msvcrt DLL),
+        # and the versions that are a single DLL are no longer supported
+        # by Microsoft.
+        return None
 
     def find_library(name):
         if name in ('c', 'm'):
-            return find_msvcrt()
+            # See gh-67794; there is no single VC runtime DLL anymore.
+            return None
         # See MSDN for the REAL search order.
         for directory in os.environ['PATH'].split(os.pathsep):
             fname = os.path.join(directory, name)

Lib/test/test_asyncio/test_protocols.py

@@ -2,6 +2,7 @@
 from unittest import mock
 
 import asyncio
+from asyncio import protocols
 
 
 def tearDownModule():
@@ -63,5 +64,32 @@ def test_subprocess_protocol(self):
         self.assertNotHasAttr(sp, '__dict__')
 
 
-if __name__ == '__main__':
+class FeedDataToBufferedProtoTests(unittest.TestCase):
+    def _make_proto(self, bufsize):
+        received = bytearray()
+        buf = bytearray(bufsize)
+
+        class P(asyncio.BufferedProtocol):
+            def get_buffer(self, sizehint):
+                return buf
+
+            def buffer_updated(self, nbytes):
+                received.extend(buf[:nbytes])
+
+        return P(), received
+
+    def test_large_multi_iteration(self):
+        proto, received = self._make_proto(64)
+        data = bytes(range(256)) * 16
+        protocols._feed_data_to_buffered_proto(proto, data)
+        self.assertEqual(bytes(received), data)
+
+    def test_memoryview_input(self):
+        proto, received = self._make_proto(64)
+        payload = b"y" * 200
+        protocols._feed_data_to_buffered_proto(proto, memoryview(payload))
+        self.assertEqual(bytes(received), payload)
+
+
+if __name__ == "__main__":
     unittest.main()

Misc/NEWS.d/next/Library/2026-07-23-13-09-25.gh-issue-154199.hmBfrS.rst

@@ -0,0 +1,2 @@
+Make :func:`ctypes.util.find_msvcrt` always return ``None`` for
+compatibility reasons.

Modules/mathintegermodule.c

@@ -180,10 +180,9 @@ that the bound `(a - 1)**2 < (n >> s) < (a + 1)**2` is maintained from one
 iteration to the next. A sketch of the proof of this is given below.
 
 In addition to the proof sketch, a formal, computer-verified proof
-of correctness (using Lean) of an equivalent recursive algorithm can be found
-here:
+of correctness (using Lean) of the algorithm can be found here:
 
-    https://github.com/mdickinson/snippets/blob/master/proofs/isqrt/src/isqrt.lean
+    https://github.com/mdickinson/snippets/tree/41ce2d256fef06fb32f24fe7014cfa95173ac5e0/proofs/isqrt
 
 
 Here's Python code equivalent to the C implementation below: