2 files changed, 27 insertions, 0 deletions
diff --git a/Doc/c-api/init.rst b/Doc/c-api/init.rst
index 41fd4ea14ef..409539dec17 100644
--- a/Doc/c-api/init.rst
+++ b/Doc/c-api/init.rst
@@ -2277,6 +2277,18 @@ The C-API provides a basic mutual exclusion lock.
 
    .. versionadded:: 3.13
 
+.. c:function:: int PyMutex_IsLocked(PyMutex *m)
+
+   Returns non-zero if the mutex *m* is currently locked, zero otherwise.
+
+   .. note::
+
+      This function is intended for use in assertions and debugging only and
+      should not be used to make concurrency control decisions, as the lock
+      state may change immediately after the check.
+
+   .. versionadded:: next
+
 .. _python-critical-section-api:
 
 Python Critical Section API
diff --git a/Doc/c-api/object.rst b/Doc/c-api/object.rst
index 0fd159f1eb8..21fa1491b33 100644
--- a/Doc/c-api/object.rst
+++ b/Doc/c-api/object.rst
@@ -197,6 +197,13 @@ Object Protocol
    in favour of using :c:func:`PyObject_DelAttr`, but there are currently no
    plans to remove it.
 
+   The function must not be called with ``NULL`` *v* and an an exception set.
+   This case can arise from forgetting ``NULL`` checks and would delete the
+   attribute.
+
+   .. versionchanged:: next
+      Must not be called with NULL value if an exception is set.
+
 
 .. c:function:: int PyObject_SetAttrString(PyObject *o, const char *attr_name, PyObject *v)
 
@@ -207,6 +214,10 @@ Object Protocol
    If *v* is ``NULL``, the attribute is deleted, but this feature is
    deprecated in favour of using :c:func:`PyObject_DelAttrString`.
 
+   The function must not be called with ``NULL`` *v* and an an exception set.
+   This case can arise from forgetting ``NULL`` checks and would delete the
+   attribute.
+
    The number of different attribute names passed to this function
    should be kept small, usually by using a statically allocated string
    as *attr_name*.
@@ -215,6 +226,10 @@ Object Protocol
    For more details, see :c:func:`PyUnicode_InternFromString`, which may be
    used internally to create a key object.
 
+   .. versionchanged:: next
+      Must not be called with NULL value if an exception is set.
+
+
 .. c:function:: int PyObject_GenericSetAttr(PyObject *o, PyObject *name, PyObject *value)
 
    Generic attribute setter and deleter function that is meant