gh-67056: document that registering/unregistering an atexit func from within an atexit func is undefined (#104473)
diff --git a/Doc/library/atexit.rst b/Doc/library/atexit.rst
index f7f0381..a2bd85b 100644
--- a/Doc/library/atexit.rst
+++ b/Doc/library/atexit.rst
@@ -20,6 +20,9 @@
program is killed by a signal not handled by Python, when a Python fatal
internal error is detected, or when :func:`os._exit` is called.
+**Note:** The effect of registering or unregistering functions from within
+a cleanup function is undefined.
+
.. versionchanged:: 3.7
When used with C-API subinterpreters, registered functions
are local to the interpreter they were registered in.
diff --git a/Misc/NEWS.d/next/Documentation/2023-05-14-12-11-28.gh-issue-67056.nVC2Rf.rst b/Misc/NEWS.d/next/Documentation/2023-05-14-12-11-28.gh-issue-67056.nVC2Rf.rst
new file mode 100644
index 0000000..2c6ef17
--- /dev/null
+++ b/Misc/NEWS.d/next/Documentation/2023-05-14-12-11-28.gh-issue-67056.nVC2Rf.rst
@@ -0,0 +1,2 @@
+Document that the effect of registering or unregistering an :mod:`atexit`
+cleanup function from within a registered cleanup function is undefined.
