📝 Add what’s new in Python 3.15

* Add lacy imports
* Add frozendict
* Add unpacking in comprehensions

Author: veit

CHANGELOG.rst

@@ -19,6 +19,12 @@ emergencies when we need to start branches for older versions.
 Added
 ~~~~~
 
+* 📝 Add what’s new in Python 3.15
+
+  * Add lacy imports
+  * Add frozendict
+  * Add unpacking in comprehensions
+
 * 📝 Add timezones
 * 📝 Add pytest-leak-finder
 

docs/control-flow/loops.rst

@@ -180,6 +180,27 @@ Das allgemeine Format für Dict Comprehensions ist:
 
 :samp:`{NEW_DICT} = \{{KEY}: {VALUE} for {MEMBER} in {ITERABLE}\}`
 
+.. _unpacking_in_comprehensions:
+
+Unpack
+~~~~~~
+
+.. versionadded:: 3.15
+
+   In line with :pep:`798`, :doc:`../types/sequences-sets/lists`,
+   :doc:`../types/sequences-sets/sets` and :doc:`../types/dicts` now support
+   comprehensions using ``*`` and ``**``:
+
+   .. code-block:: pycon
+
+      >>> nested_list = [[0, 1], [2, 3], [4, 5]]
+      >>> [*l for l in nested_list]
+      [0, 1, 2, 3, 4, 5]
+      >>>
+      >>> nested_dict = [{0: "a"}, {1: "b"}, {2: "c"}]
+      >>> {**d for d in nested_dict}
+      {0: 'a', 1: 'b', 2: 'c'}
+
 Change a ``Collection``
 ~~~~~~~~~~~~~~~~~~~~~~~
 

docs/modules/index.rst

@@ -48,6 +48,31 @@ provided via special modules that you can load as needed.
 .. seealso::
     * :ref:`python3:py-modindex`
 
+.. _explicit-lazy-imports:
+
+.. versionadded:: 3.15
+
+   Python 3.15 introduces explicit lazy imports via :pep:`810`: if an ``import``
+   statement is prefixed with the keyword ``lazy``, the module is not loaded
+   immediately; instead, a proxy object is created. The actual module is loaded
+   the first time it is used:
+
+   .. code-block:: pycon
+
+      >>> import sys
+      >>> lazy import json
+      >>> lazy from pathlib import Path
+      >>> "json" in sys.modules
+      False
+      >>> with Path.open("books.json") as f:
+      ...     data = json.load(f)
+      ...
+      >>> "json" in sys.modules
+      True
+
+   .. seealso::
+      * :ref:`lazy-imports`
+
 Creating modules
 ----------------
 

docs/types/dicts.rst

@@ -109,6 +109,46 @@ keys of a dict, for example:
       >>> collections.Counter(titles)
       Counter({'Lists': 2, 'Data types': 1, 'Sets': 1})
 
+.. _frozendict:
+
+``frozendict``
+--------------
+
+.. versionadded:: 3.15
+
+   :pep:`814` introduces :class:`python3:frozendict`, an :term:`immutable`
+   dictionary:
+
+   .. code-block:: pycon
+
+      >>> titles = frozendict({7.0: "Data Types", 7.1: "Lists", 7.2: "Tuples"})
+      >>> titles
+      frozendict({7.0: 'Data Types', 7.1: 'Lists', 7.2: 'Tuples'})
+      >>> titles[7.3] = "Sets"
+      Traceback (most recent call last):
+        File "<python-input-16>", line 1, in <module>
+          titles[7.3] = "Sets"
+          ~~~~~~^^^^^
+      TypeError: 'frozendict' object does not support item assignment
+
+   Immutable mappings are hashable, which means they can be used as keys in
+   dictionaries, as elements in :doc:`sets <sequences-sets/sets>`, or accepted
+   as arguments by functions :doc:`decorated <../functions/decorators>` with
+   :func:`@functools.lru_cache`:
+
+   .. code-block:: pycon
+
+      >>> hash(titles)
+      3827265406416199624
+
+   The merge operator (``|``) can be used to merge two ``frozendict`` objects or
+   a ``frozendict`` object with a ``dict`` object, for example:
+
+   .. code-block:: pycon
+
+      >>> titles | new_titles
+      frozendict({7.0: 'Data types', 7.1: 'Lists', 7.2: 'Tuples', 7.3: 'Sets'})
+
 Extensions
 ----------
 

docs/types/index.rst

@@ -40,6 +40,9 @@ appropriate special method attributes.
 Python has several built-in data types, from scalars like numbers and boolean
 values to more complex structures like lists, dictionaries and files.
 
+.. seealso::
+   * :doc:`python3:builtins/stdtypes`
+
 .. toctree::
    :titlesonly:
    :hidden:

docs/types/strings/encodings.rst

@@ -111,6 +111,8 @@ defines several different encodings from a single character set. UTF-8 is an
 encoding scheme for representing Unicode characters as binary data with one or
 more bytes per character.
 
+.. _default-encoding:
+
 .. versionadded:: 3.15
    Python 3.15 uses UTF-8 as the default encoding, regardless of the system
    environment. This means that I/O operations without explicit encoding, for