gh-96197: Define the behavior of breakpoint if sys.breakpointhook is lost (gh-96231)

diff --git a/Doc/library/functions.rst b/Doc/library/functions.rst
index da7de18722f87e3c07258d9fd83e8713fcc07896..fbde9129274e9567738e0551321a005899837b36 100644 (file)
--- a/Doc/library/functions.rst
+++ b/Doc/library/functions.rst
@@ -164,6 +164,8 @@ are always available.  They are listed here in alphabetical order.
    :func:`sys.breakpointhook` can be set to some other function and
    :func:`breakpoint` will automatically call that, allowing you to drop into
    the debugger of choice.
+   If :func:`sys.breakpointhook` is not available to be called, this function will
+   raise :exc:`RuntimeError`.
 
    .. audit-event:: builtins.breakpoint breakpointhook breakpoint