Sync pre-release CPython 3.15 branch from GitHub (2026-05-31)

Summary:
Imported python/cpython `3.15.0b1+` from upstream rev [`487b23d`](https://www.github.com/python/cpython/commit/487b23d546d265cab7809bc166097f7ed0843968) (committed 2026-05-31 20:12:22+00:00).

# Commit Info

- Base: (`3.15.0b1+`) - [`9a39343`](https://www.github.com/python/cpython/commit/9a393438a7e30f4909c288a90f7637f4ce68e21a) (commit date: 2026-05-31 04:22:11+00:00)
- Imported: (`3.15.0b1+`) - [`487b23d`](https://www.github.com/python/cpython/commit/487b23d546d265cab7809bc166097f7ed0843968) (commit date: 2026-05-31 20:12:22+00:00)

# Noteworthy file changes

- Stdlib files (1 added, 1 removed)
- Low-signal files (1 added) (NEWS.d, docs, .github)

Complete list of added/removed files: https://www.internalfb.com/intern/everpaste/?color=0&handle=GOn7tyJfb8V4k2gFAHRM4UaOgFQBbr0LAAAz

Differential Revision: D107043262

fbshipit-source-id: d67cdfeab99369b708c5b444f02c67f1fbda04b5

Author: generatedunixname1734921407115435

Doc/library/binascii.rst

@@ -367,9 +367,8 @@ The :mod:`!binascii` module defines the following functions:
    *ignorechars* should be a :term:`bytes-like object` containing characters
    to ignore from the input.
 
-   Similar functionality (accepting only text string arguments, but more
-   liberal towards whitespace) is also accessible using the
-   :meth:`bytes.fromhex` class method.
+   Similar functionality (but more liberal towards whitespace) is also accessible
+   using the :meth:`bytes.fromhex` class method.
 
    .. versionchanged:: 3.15
       Added the *ignorechars* parameter.

Doc/library/copy.rst

@@ -72,9 +72,13 @@ file, socket, window, or any similar types.  It does "copy" functions and
 classes (shallow and deeply), by returning the original object unchanged; this
 is compatible with the way these are treated by the :mod:`pickle` module.
 
-Shallow copies of dictionaries can be made using :meth:`dict.copy`, and
-of lists by assigning a slice of the entire list, for example,
-``copied_list = original_list[:]``.
+Shallow copies of many collections can be made using the corresponding
+:meth:`!copy` method (such as :meth:`list.copy`, :meth:`dict.copy` or
+:meth:`set.copy`), and of sequences (such as lists or bytearrays) by making
+a slice of the entire sequence (``sequence[:]``).
+However, these methods and slicing can create an instance of the base type
+when copying an instance of a subclass, whereas :func:`copy.copy` normally
+returns an instance of the same type.
 
 .. index:: pair: module; pickle
 

Doc/library/gettext.rst

@@ -51,19 +51,19 @@ class-based API instead.
 
 
 .. index:: single: _ (underscore); gettext
-.. function:: gettext(message)
+.. function:: gettext(message, /)
 
    Return the localized translation of *message*, based on the current global
    domain, language, and locale directory.  This function is usually aliased as
    :func:`!_` in the local namespace (see examples below).
 
 
-.. function:: dgettext(domain, message)
+.. function:: dgettext(domain, message, /)
 
    Like :func:`.gettext`, but look the message up in the specified *domain*.
 
 
-.. function:: ngettext(singular, plural, n)
+.. function:: ngettext(singular, plural, n, /)
 
    Like :func:`.gettext`, but consider plural forms. If a translation is found,
    apply the plural formula to *n*, and return the resulting message (some
@@ -78,15 +78,15 @@ class-based API instead.
    formulas for a variety of languages.
 
 
-.. function:: dngettext(domain, singular, plural, n)
+.. function:: dngettext(domain, singular, plural, n, /)
 
    Like :func:`ngettext`, but look the message up in the specified *domain*.
 
 
-.. function:: pgettext(context, message)
-.. function:: dpgettext(domain, context, message)
-.. function:: npgettext(context, singular, plural, n)
-.. function:: dnpgettext(domain, context, singular, plural, n)
+.. function:: pgettext(context, message, /)
+.. function:: dpgettext(domain, context, message, /)
+.. function:: npgettext(context, singular, plural, n, /)
+.. function:: dnpgettext(domain, context, singular, plural, n, /)
 
    Similar to the corresponding functions without the ``p`` in the prefix (that
    is, :func:`gettext`, :func:`dgettext`, :func:`ngettext`, :func:`dngettext`),
@@ -223,28 +223,28 @@ are the methods of :class:`!NullTranslations`:
       translation for a given message.
 
 
-   .. method:: gettext(message)
+   .. method:: gettext(message, /)
 
       If a fallback has been set, forward :meth:`!gettext` to the fallback.
       Otherwise, return *message*.  Overridden in derived classes.
 
 
-   .. method:: ngettext(singular, plural, n)
+   .. method:: ngettext(singular, plural, n, /)
 
       If a fallback has been set, forward :meth:`!ngettext` to the fallback.
       Otherwise, return *singular* if *n* is 1; return *plural* otherwise.
       Overridden in derived classes.
 
 
-   .. method:: pgettext(context, message)
+   .. method:: pgettext(context, message, /)
 
       If a fallback has been set, forward :meth:`pgettext` to the fallback.
       Otherwise, return the translated message.  Overridden in derived classes.
 
       .. versionadded:: 3.8
 
 
-   .. method:: npgettext(context, singular, plural, n)
+   .. method:: npgettext(context, singular, plural, n, /)
 
       If a fallback has been set, forward :meth:`npgettext` to the fallback.
       Otherwise, return the translated message.  Overridden in derived classes.
@@ -322,7 +322,7 @@ unexpected, or if other problems occur while reading the file, instantiating a
 
    The following methods are overridden from the base class implementation:
 
-   .. method:: gettext(message)
+   .. method:: gettext(message, /)
 
       Look up the *message* id in the catalog and return the corresponding message
       string, as a Unicode string.  If there is no entry in the catalog for the
@@ -331,7 +331,7 @@ unexpected, or if other problems occur while reading the file, instantiating a
       *message* id is returned.
 
 
-   .. method:: ngettext(singular, plural, n)
+   .. method:: ngettext(singular, plural, n, /)
 
       Do a plural-forms lookup of a message id.  *singular* is used as the message id
       for purposes of lookup in the catalog, while *n* is used to determine which
@@ -352,7 +352,7 @@ unexpected, or if other problems occur while reading the file, instantiating a
              n) % {'num': n}
 
 
-   .. method:: pgettext(context, message)
+   .. method:: pgettext(context, message, /)
 
       Look up the *context* and *message* id in the catalog and return the
       corresponding message string, as a Unicode string.  If there is no
@@ -363,7 +363,7 @@ unexpected, or if other problems occur while reading the file, instantiating a
       .. versionadded:: 3.8
 
 
-   .. method:: npgettext(context, singular, plural, n)
+   .. method:: npgettext(context, singular, plural, n, /)
 
       Do a plural-forms lookup of a message id.  *singular* is used as the
       message id for purposes of lookup in the catalog, while *n* is used to

Doc/library/math.rst

@@ -255,10 +255,12 @@ Floating point manipulation functions
 
 .. function:: frexp(x)
 
-   Return the mantissa and exponent of *x* as the pair ``(m, e)``.  *m* is a float
-   and *e* is an integer such that ``x == m * 2**e`` exactly. If *x* is zero,
-   returns ``(0.0, 0)``, otherwise ``0.5 <= abs(m) < 1``.  This is used to "pick
-   apart" the internal representation of a float in a portable way.
+   Return the mantissa and exponent of *x* as the pair ``(m, e)``.
+   If *x* is a finite nonzero number, then *m* is a float with
+   ``0.5 <= abs(m) < 1.0`` and an integer *e* is such that
+   ``x == m * 2**e`` exactly.  Else, return ``(x, 0)``.
+   This is used to "pick apart" the internal representation of
+   a float in a portable way.
 
    Note that :func:`frexp` has a different call/return pattern
    than its C equivalents: it takes a single argument and return a pair of

Doc/library/mimetypes.rst

@@ -348,7 +348,7 @@ it converts file extensions to MIME types.
 
 For each ``type`` entry, the script writes a line into the standard output
 stream. If an unknown type occurs, it writes an error message into the
-standard error stream and exits with the return code ``1``.
+standard output stream and exits with the return code ``1``.
 
 
 .. mimetypes-cli-example:
@@ -375,7 +375,7 @@ interface:
 
    $ # get a MIME type for a rare file extension
    $ python -m mimetypes filename.pict
-   error: unknown extension of filename.pict
+   error: media type unknown for filename.pict
 
    $ # now look in the extended database built into Python
    $ python -m mimetypes --lenient filename.pict
@@ -397,7 +397,8 @@ interface:
    $ python -m mimetypes filename.sh filename.nc filename.xxx filename.txt
    type: application/x-sh encoding: None
    type: application/x-netcdf encoding: None
-   error: unknown extension of filename.xxx
+   error: media type unknown for filename.xxx
+   type: text/plain encoding: None
 
    $ # try to feed an unknown MIME type
    $ python -m mimetypes --extension audio/aac audio/opus audio/future audio/x-wav

Doc/library/multiprocessing.rst

@@ -1723,7 +1723,10 @@ inherited by child processes.
    Note that *lock* is a keyword only argument.
 
    Note that an array of :data:`ctypes.c_char` has *value* and *raw*
-   attributes which allow one to use it to store and retrieve strings.
+   attributes which can both be used to store and retrieve byte strings.
+   While *raw* allows interaction with a :class:`bytes` object the full size of
+   the array, reading *value* will terminate after a null byte, like most
+   programming languages handle strings.
 
 
 The :mod:`!multiprocessing.sharedctypes` module

Doc/library/sched.rst

@@ -117,9 +117,11 @@ Scheduler Objects
    function passed to the constructor) for the next event, then execute it and so
    on until there are no more scheduled events.
 
-   If *blocking* is false executes the scheduled events due to expire soonest
-   (if any) and then return the deadline of the next scheduled call in the
-   scheduler (if any).
+   If *blocking* is false, immediately executes all events in the queue which have
+   a time value less than or equal to the current *timefunc* value (if any) and
+   returns the difference between the current *timefunc* value and the time value
+   of the next scheduled event in the scheduler's event queue.  If the queue is
+   empty, returns ``None``.
 
    Either *action* or *delayfunc* can raise an exception.  In either case, the
    scheduler will maintain a consistent state and propagate the exception.  If an

Lib/ensurepip/__init__.py

@@ -10,7 +10,7 @@
 
 
 __all__ = ["version", "bootstrap"]
-_PIP_VERSION = "26.1.1"
+_PIP_VERSION = "26.1.2"
 
 # Directory of system wheel packages. Some Linux distribution packaging
 # policies recommend against bundling dependencies. For example, Fedora

…pip/_bundled/pip-26.1.1-py3-none-any.whl …pip/_bundled/pip-26.1.2-py3-none-any.whlLib/ensurepip/_bundled/pip-26.1.1-py3-none-any.whl renamed to Lib/ensurepip/_bundled/pip-26.1.2-py3-none-any.whl Lib/ensurepip/_bundled/pip-26.1.1-py3-none-any.whl renamed to Lib/ensurepip/_bundled/pip-26.1.2-py3-none-any.whl

@@ -6,8 +6,9 @@
 import unittest.mock
 from platform import win32_edition
 from test import support
-from test.support import cpython_only, force_not_colorized, os_helper
+from test.support import cpython_only, force_not_colorized, os_helper, requires_subprocess
 from test.support.import_helper import ensure_lazy_imports
+from test.support.script_helper import assert_python_ok, assert_python_failure
 
 try:
     import _winapi
@@ -508,5 +509,59 @@ def test_invocation_error(self):
                 self.assertEqual(result, expected)
 
 
+@requires_subprocess()
+class CommandLineSubprocessTest(unittest.TestCase):
+    def test_help(self):
+        rc, stdout, stderr = assert_python_ok('-m', 'mimetypes', '--help')
+        self.assertIn(b'mimetypes', stdout)
+        self.assertIn(b'--extension', stdout)
+        self.assertIn(b'--lenient', stdout)
+
+    def test_type_lookup(self):
+        rc, stdout, stderr = assert_python_ok('-m', 'mimetypes', 'foo.pdf')
+        self.assertEqual(stdout.strip(), b'type: application/pdf encoding: None')
+        self.assertEqual(stderr, b'')
+
+    def test_type_lookup_unknown(self):
+        rc, stdout, stderr = assert_python_failure('-m', 'mimetypes', 'foo.unknownext12345')
+        self.assertEqual(stdout.strip(), b'error: media type unknown for foo.unknownext12345')
+        self.assertEqual(stderr, b'')
+
+    def test_extension_flag(self):
+        rc, stdout, stderr = assert_python_ok('-m', 'mimetypes', '-e', 'image/jpeg')
+        self.assertEqual(stdout.strip(), b'.jpg')
+        self.assertEqual(stderr, b'')
+
+    def test_extension_flag_unknown(self):
+        rc, stdout, stderr = assert_python_failure('-m', 'mimetypes', '-e', 'image/unknowntype12345')
+        self.assertEqual(stdout.strip(), b'error: unknown type image/unknowntype12345')
+        self.assertEqual(stderr, b'')
+
+    def test_lenient_flag(self):
+        rc, stdout, stderr = assert_python_ok('-m', 'mimetypes', '-e', '--lenient', 'text/xul')
+        self.assertIn(b'.xul', stdout)
+        self.assertEqual(stderr, b'')
+
+    def test_multiple_inputs(self):
+        rc, stdout, stderr = assert_python_ok('-m', 'mimetypes', 'foo.pdf', 'foo.png')
+        self.assertIn(b'type: application/pdf encoding: None', stdout)
+        self.assertIn(b'type: image/png encoding: None', stdout)
+        self.assertEqual(stderr, b'')
+
+    def test_multiple_inputs_with_error(self):
+        rc, stdout, stderr = assert_python_failure(
+            '-m', 'mimetypes', 'foo.pdf', 'foo.unknownext12345'
+        )
+        self.assertIn(b'type: application/pdf encoding: None', stdout)
+        self.assertIn(b'error: media type unknown for foo.unknownext12345', stdout)
+        self.assertEqual(stderr, b'')
+
+    @force_not_colorized
+    def test_unknown_flag(self):
+        rc, stdout, stderr = assert_python_failure('-m', 'mimetypes', '--unknown-flag', 'foo.pdf')
+        self.assertEqual(stdout, b'')
+        self.assertIn(b'error: unrecognized arguments: --unknown-flag', stderr)
+
+
 if __name__ == "__main__":
     unittest.main()