Import CPython 3.14.6+ stable branch (2026-07-25)

Summary:
Imported python/cpython `3.14.6+` from upstream rev [`e76d333`](https://www.github.com/python/cpython/commit/e76d3333cbfa82e32aa4f8cf0b52d2664e90eb44) (committed 2026-07-25 03:56:33+00:00).

# Commit Info

- Base: (`3.14.6+`) - [`37a5c69`](https://www.github.com/python/cpython/commit/37a5c690d033099276c8a264c1a660819863bd68) (commit date: 2026-07-23 08:21:52+00:00)
- Imported: (`3.14.6+`) - [`e76d333`](https://www.github.com/python/cpython/commit/e76d3333cbfa82e32aa4f8cf0b52d2664e90eb44) (commit date: 2026-07-25 03:56:33+00:00)

# Noteworthy file changes

- Native files (1 added):
  ```
  + Modules/_testlimitedcapi/capsule.c
  ```
- Test files (1 added)
- Low-signal files (10 added) (NEWS.d, docs, .github)

Complete list of added/removed files: https://www.internalfb.com/intern/everpaste/?color=0&handle=GLTSliGeK1K9mLoDAABDYUCHmlkObr0LAAAz

Reviewed By: yoney

Differential Revision: D113652391

fbshipit-source-id: d976418ac47696613ec8b0e283f50d65d8e5c85f

Author: itamaro

.github/workflows/build.yml

@@ -187,9 +187,14 @@ jobs:
       - name: Check for unsupported C global variables
         if: github.event_name == 'pull_request'  # $GITHUB_EVENT_NAME
         run: make check-c-globals
-      - name: Check for undocumented C APIs
-        run: make check-c-api-docs
 
+  check-c-api-docs:
+    name: C API Docs
+    needs: build-context
+    if: >-
+      needs.build-context.outputs.run-tests == 'true'
+      || needs.build-context.outputs.run-docs == 'true'
+    uses: ./.github/workflows/reusable-check-c-api-docs.yml
 
   build-windows:
     name: >-
@@ -674,6 +679,7 @@ jobs:
     - check-docs
     - check-autoconf-regen
     - check-generated-files
+    - check-c-api-docs
     - build-windows
     - build-windows-msi
     - build-macos
@@ -710,6 +716,12 @@ jobs:
             '
             || ''
           }}
+          ${{
+            !fromJSON(needs.build-context.outputs.run-tests)
+            && !fromJSON(needs.build-context.outputs.run-docs)
+            && 'check-c-api-docs,'
+            || ''
+          }}
           ${{ !fromJSON(needs.build-context.outputs.run-windows-tests) && 'build-windows,' || '' }}
           ${{
             !fromJSON(needs.build-context.outputs.run-ci-fuzz)

.github/workflows/reusable-check-c-api-docs.yml

@@ -0,0 +1,25 @@
+name: Reusable C API Docs Check
+
+on:
+  workflow_call:
+
+permissions:
+  contents: read
+
+env:
+  FORCE_COLOR: 1
+
+jobs:
+  check-c-api-docs:
+    name: 'Check if all C APIs are documented'
+    runs-on: ubuntu-latest
+    timeout-minutes: 5
+    steps:
+      - uses: actions/checkout@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0 # v7.0.0
+        with:
+          persist-credentials: false
+      - uses: actions/setup-python@a309ff8b426b58ec0e2a45f0f869d46889d02405 # v6.2.0
+        with:
+          python-version: '3.x'
+      - name: Check for undocumented C APIs
+        run: python Tools/check-c-api-docs/main.py

Doc/library/difflib.rst

@@ -44,13 +44,18 @@ diffs. For comparing directories and files, see also, the :mod:`filecmp` module.
    complicated way on how many elements the sequences have in common; best case
    time is linear.
 
-   **Automatic junk heuristic:** :class:`SequenceMatcher` supports a heuristic that
-   automatically treats certain sequence items as junk. The heuristic counts how many
-   times each individual item appears in the sequence. If an item's duplicates (after
-   the first one) account for more than 1% of the sequence and the sequence is at least
-   200 items long, this item is marked as "popular" and is treated as junk for
-   the purpose of sequence matching. This heuristic can be turned off by setting
-   the ``autojunk`` argument to ``False`` when creating the :class:`SequenceMatcher`.
+   **Junk**: :class:`SequenceMatcher` accepts an ``isjunk`` predicate and an
+   ``autojunk`` flag. Items that are considered as junk will not be considered
+   to find similar content blocks. This can produce better results for humans
+   (typically breaking on whitespace) and faster (because it reduces the number
+   of possible combinations). But it can also cause pathological cases where
+   too many items considered junk cause an unexpectedly large (but correct)
+   diff result.
+   You should consider tuning them or turning them off depending on your data.
+   Moreover, only the second sequence is inspected for junk. This causes the diff
+   output to not be symmetrical.
+   When ``autojunk=True``, it will consider as junk the items that account for more
+   than 1% of the sequence, if it is at least 200 items long.
 
    .. versionchanged:: 3.2
       Added the *autojunk* parameter.
@@ -554,16 +559,6 @@ The :class:`SequenceMatcher` class has this constructor:
       to try :meth:`quick_ratio` or :meth:`real_quick_ratio` first to get an
       upper bound.
 
-      .. note::
-
-         Caution: The result of a :meth:`ratio` call may depend on the order of
-         the arguments. For instance::
-
-            >>> SequenceMatcher(None, 'tide', 'diet').ratio()
-            0.25
-            >>> SequenceMatcher(None, 'diet', 'tide').ratio()
-            0.5
-
 
    .. method:: quick_ratio()
 

Lib/asyncio/base_subprocess.py

@@ -22,7 +22,7 @@ def __init__(self, loop, protocol, args, shell,
         self._proc = None
         self._pid = None
         self._returncode = None
-        self._exit_waiters = []
+        self._exit_waiters = set()
         self._pending_calls = collections.deque()
         self._pipes = {}
         self._finished = False
@@ -211,6 +211,14 @@ async def _connect_pipes(self, waiter):
         except (SystemExit, KeyboardInterrupt):
             raise
         except BaseException as exc:
+            # Close any pipes that were already connected before the
+            # error/cancellation to avoid leaking file descriptors.
+            for proto in self._pipes.values():
+                if proto is not None:
+                    proto.pipe.close()
+            for raw_pipe in (proc.stdin, proc.stdout, proc.stderr):
+                if raw_pipe is not None:
+                    raw_pipe.close()
             if waiter is not None and not waiter.cancelled():
                 waiter.set_exception(exc)
         else:
@@ -260,8 +268,12 @@ async def _wait(self):
             return self._returncode
 
         waiter = self._loop.create_future()
-        self._exit_waiters.append(waiter)
-        return await waiter
+        self._exit_waiters.add(waiter)
+        try:
+            return await waiter
+        finally:
+            if self._exit_waiters is not None:
+                self._exit_waiters.discard(waiter)
 
     def _try_finish(self):
         assert not self._finished

Lib/asyncio/selector_events.py

@@ -582,14 +582,10 @@ def _sock_sendall(self, fut, sock, view, pos):
             pos[0] = start
 
     async def sock_sendto(self, sock, data, address):
-        """Send data to the socket.
+        """Send a datagram from sock to address.
 
-        The socket must be connected to a remote socket.  This method
-        continues to send data from data until either all data has been
-        sent or an error occurs.  None is returned on success.  On error,
-        an exception is raised, and there is no way to determine how much
-        data, if any, was successfully processed by the receiving end of
-        the connection.
+        The socket does not have to be connected. This method sends the
+        whole datagram in a single call. Return the number of bytes sent.
         """
         base_events._check_ssl_socket(sock)
         if self._debug and sock.gettimeout() != 0:

Lib/asyncio/unix_events.py

@@ -212,7 +212,7 @@ async def _make_subprocess_transport(self, protocol, args, shell,
             raise
         except BaseException:
             transp.close()
-            await transp._wait()
+            await tasks.shield(transp._wait())
             raise
 
         return transp
@@ -639,7 +639,8 @@ def __init__(self, loop, pipe, protocol, waiter=None, extra=None):
         self._conn_lost = 0
         self._closing = False  # Set when close() or write_eof() called.
 
-        mode = os.fstat(self._fileno).st_mode
+        pipe_stat = os.fstat(self._fileno)
+        mode = pipe_stat.st_mode
         is_char = stat.S_ISCHR(mode)
         is_fifo = stat.S_ISFIFO(mode)
         is_socket = stat.S_ISSOCK(mode)
@@ -656,7 +657,19 @@ def __init__(self, loop, pipe, protocol, waiter=None, extra=None):
         # On AIX, the reader trick (to be notified when the read end of the
         # socket is closed) only works for sockets. On other platforms it
         # works for pipes and sockets. (Exception: OS X 10.4?  Issue #19294.)
-        if is_socket or (is_fifo and not sys.platform.startswith("aix")):
+        # On macOS, the trick misfires for named FIFOs (but not for pipes
+        # created with os.pipe(), which have st_nlink == 0): the write end
+        # polls as readable whenever unread data sits in the FIFO, and no
+        # event is delivered when the read end is closed, so it can only
+        # ever report a false disconnection (gh-145030). The same xnu
+        # behaviour applies on iOS/tvOS/watchOS (sys.platform is not
+        # "darwin" there).
+        is_named_fifo_on_apple = (
+            sys.platform in {"darwin", "ios", "tvos", "watchos"}
+            and is_fifo and pipe_stat.st_nlink > 0)
+        if is_socket or (is_fifo
+                         and not sys.platform.startswith("aix")
+                         and not is_named_fifo_on_apple):
             # only start reading when connection_made() has been called
             self._loop.call_soon(self._loop._add_reader,
                                  self._fileno, self._read_ready)

Lib/asyncio/windows_events.py

@@ -408,7 +408,7 @@ async def _make_subprocess_transport(self, protocol, args, shell,
             raise
         except BaseException:
             transp.close()
-            await transp._wait()
+            await tasks.shield(transp._wait())
             raise
 
         return transp

Lib/ctypes/util.py

@@ -421,8 +421,7 @@ def _findLib_ld(name):
             result = None
             try:
                 p = subprocess.Popen(cmd, stdout=subprocess.PIPE,
-                                     stderr=subprocess.PIPE,
-                                     universal_newlines=True)
+                                     stderr=subprocess.PIPE)
                 out, _ = p.communicate()
                 res = re.findall(expr, os.fsdecode(out))
                 for file in res:

Lib/logging/config.py

@@ -32,6 +32,7 @@
 import os
 import queue
 import re
+import socket
 import struct
 import threading
 import traceback
@@ -1022,6 +1023,15 @@ class ConfigSocketReceiver(ThreadingTCPServer):
 
         def __init__(self, host='localhost', port=DEFAULT_LOGGING_CONFIG_PORT,
                      handler=None, ready=None, verify=None):
+            # The host can have no IPv4 address, for example if "localhost"
+            # is only aliased to ::1.  Leave resolution errors to the server.
+            try:
+                infos = socket.getaddrinfo(host, port, type=socket.SOCK_STREAM)
+            except OSError:
+                pass
+            else:
+                if not any(info[0] == socket.AF_INET for info in infos):
+                    self.address_family = infos[0][0]
             ThreadingTCPServer.__init__(self, (host, port), handler)
             with logging._lock:
                 self.abort = 0
@@ -1053,9 +1063,14 @@ def __init__(self, rcvr, hdlr, port, verify):
             self.ready = threading.Event()
 
         def run(self):
-            server = self.rcvr(port=self.port, handler=self.hdlr,
-                               ready=self.ready,
-                               verify=self.verify)
+            try:
+                server = self.rcvr(port=self.port, handler=self.hdlr,
+                                   ready=self.ready,
+                                   verify=self.verify)
+            except BaseException:
+                # Do not leave the caller waiting for ready forever.
+                self.ready.set()
+                raise
             if self.port == 0:
                 self.port = server.server_address[1]
             self.ready.set()

Lib/test/test_asyncio/test_events.py

@@ -1725,6 +1725,48 @@ def reader(data):
         self.loop.run_until_complete(proto.done)
         self.assertEqual('CLOSED', proto.state)
 
+    @unittest.skipUnless(sys.platform != 'win32',
+                         "Don't support pipes for Windows")
+    @unittest.skipUnless(hasattr(os, 'mkfifo'), 'requires os.mkfifo()')
+    def test_write_named_fifo_unread_data(self):
+        # gh-145030: on macOS, the write end of a named FIFO polls as
+        # readable while unread data sits in the FIFO, which made the
+        # transport misinterpret the event as the reader hanging up
+        # and close itself.
+        path = os_helper.TESTFN
+        os.mkfifo(path)
+        self.assertNotEqual(os.stat(path).st_nlink, 0)
+        self.addCleanup(os_helper.unlink, path)
+        rfd = os.open(path, os.O_RDONLY | os.O_NONBLOCK)
+        self.addCleanup(os.close, rfd)
+        wfd = os.open(path, os.O_WRONLY | os.O_NONBLOCK)
+        pipeobj = io.open(wfd, 'wb', 1024)
+
+        proto = MyWritePipeProto(loop=self.loop)
+        connect = self.loop.connect_write_pipe(lambda: proto, pipeobj)
+        transport, p = self.loop.run_until_complete(connect)
+        self.assertIs(p, proto)
+        self.assertEqual('CONNECTED', proto.state)
+
+        transport.write(b'1')
+        # Iterate the event loop while the data stays unread in the FIFO;
+        # the transport must not detect a false disconnection.
+        for _ in range(10):
+            test_utils.run_briefly(self.loop)
+        self.assertEqual('CONNECTED', proto.state)
+        self.assertFalse(transport.is_closing())
+        self.assertEqual(b'1', os.read(rfd, 1024))
+
+        transport.write(b'2345')
+        for _ in range(10):
+            test_utils.run_briefly(self.loop)
+        self.assertEqual('CONNECTED', proto.state)
+        self.assertEqual(b'2345', os.read(rfd, 1024))
+
+        transport.close()
+        self.loop.run_until_complete(proto.done)
+        self.assertEqual('CLOSED', proto.state)
+
     @unittest.skipUnless(sys.platform != 'win32',
                          "Don't support pipes for Windows")
     def test_write_pipe_disconnect_on_close(self):