Feb 23, 2023 · Feb 13, 2023 · Feb 13, 2023 · Feb 13, 2023 · Feb 23, 2023 · Feb 23, 2023
diff --git a/Doc/library/functools.rst b/Doc/library/functools.rst
   The *cached_property* does not prevent a possible race condition in
   multi-threaded usage. The getter function could run more than once on the
   same instance, with the latest run setting the cached value. If the cached
   property is idempotent or otherwise not harmful to(in rare cases) run more
 than once on aninstance, this is fine. If synchronization is needed,
 implement the necessarylocking inside the decorated getter function or
 around the cached propertyaccess.
   property is idempotent or otherwise not harmful torun more than once on an
   instance, this is fine. If synchronization is needed, implement the necessary
   locking inside the decorated getter function or around the cached property
   access.

   Note, this decorator interferes with the operation of :pep:`412`
   key-sharing dictionaries.  This means that instance dictionaries
diff --git a/Doc/whatsnew/3.12.rst b/Doc/whatsnew/3.12.rst

 * The undocumented locking behavior of :func:`~functools.cached_property`
  is removed, because it locked across all instances of the class, leading to high
  lock contention. This means that a cached property getter function could now
 occasionally runmore than once for a single instance, if two threads race. For
 most simplecached properties (e.g. those that are idempotent and simply
 calculate a valuebased on other attributes of the instance) this will be fine.
 Ifsynchronization is needed, implement locking within the cached property
 getterfunction or around multi-threaded access points.
  lock contention. This means that a cached property getter function could now run
  more than once for a single instance, if two threads race. For most simple
  cached properties (e.g. those that are idempotent and simply calculate a value
  based on other attributes of the instance) this will be fine.  If
  synchronization is needed, implement locking within the cached property getter
  function or around multi-threaded access points.


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Original file line number	Diff line number	Diff line change
Expand Up		@@ -89,10 +89,10 @@ The :mod:`functools` module defines the following functions:
		The cached_property does not prevent a possible race condition in
		multi-threaded usage. The getter function could run more than once on the
		same instance, with the latest run setting the cached value. If the cached
		property is idempotent or otherwise not harmful to(in rare cases) run more
		than once on aninstance, this is fine. If synchronization is needed,
		implement the necessarylocking inside the decorated getter function or
		around the cached propertyaccess.
		property is idempotent or otherwise not harmful torun more than once on an
		instance, this is fine. If synchronization is needed, implement the necessary
		locking inside the decorated getter function or around the cached property
		access.

		Note, this decorator interferes with the operation of :pep:`412`
		key-sharing dictionaries. This means that instance dictionaries
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Original file line number	Diff line number	Diff line change
Expand Up		@@ -763,12 +763,12 @@ Changes in the Python API

		* The undocumented locking behavior of :func:`~functools.cached_property`
		is removed, because it locked across all instances of the class, leading to high
		lock contention. This means that a cached property getter function could now
		occasionally runmore than once for a single instance, if two threads race. For
		most simplecached properties (e.g. those that are idempotent and simply
		calculate a valuebased on other attributes of the instance) this will be fine.
		Ifsynchronization is needed, implement locking within the cached property
		getterfunction or around multi-threaded access points.
		lock contention. This means that a cached property getter function could now run
		more than once for a single instance, if two threads race. For most simple
		cached properties (e.g. those that are idempotent and simply calculate a value
		based on other attributes of the instance) this will be fine. If
		synchronization is needed, implement locking within the cached property getter
		function or around multi-threaded access points.


		Build Changes
Expand Down