PEP 781: Add deprecation and a rejected idea (#4341)

Author: methane

peps/pep-0781.rst

@@ -63,9 +63,14 @@ Static type checkers must treat ``TYPE_CHECKING`` as ``True``, similar to
 :data:`typing.TYPE_CHECKING`.
 
 If this PEP is accepted, the new ``TYPE_CHECKING`` constant will be
-the preferred approach, instead of the existing ``typing.TYPE_CHECKING``.
-However, ``typing.TYPE_CHECKING`` will not be deprecated in the foreseeable
-future.
+the preferred approach and importing ``typing.TYPE_CHECKING`` will be
+deprecated.
+To minimize the runtime impact of typing, this deprecation will generate
+``DeprecationWarning`` no sooner than Python 3.13's end of life, scheduled
+for October 2029.
+
+Instead, type checkers may warn about such deprecated usage when the target
+version of the checked program is signalled to be Python 3.14 or newer.
 
 
 Backwards Compatibility
@@ -115,6 +120,20 @@ Benefit from eliminating type-checking-only code is estimated to be not enough
 to justify the complexity.
 
 
+Optimize ``import typing``
+--------------------------
+
+Future optimizations may eliminate the need to avoid importing the ``typing``
+module for startup time.
+
+Even with such optimizations, there will still be use cases where minimizing
+imports is beneficial, such as running Python on embedded systems or
+in browsers.
+
+Therefore, defining a constant for skipping type-checking-only code outside
+the ``typing`` module remains valuable.
+
+
 Copyright
 =========