Address Erlend's review

* Change Sphinx formatting
* Don't change PyWeakref_GetObject() exception

Author: vstinner

Doc/c-api/weakref.rst

@@ -53,10 +53,10 @@ as much as it can.
 
 .. c:function:: int PyWeakref_GetRef(PyObject *ref, PyObject **pobj)
 
-   Get the referenced object from a weak reference, *ref*, into ``*pobj``.
+   Get the referenced object from a weak reference, *ref*, into *\*pobj*.
    Return 0 on success. Raise an exception and return -1 on error.
 
-   If the referent is no longer live, set ``*pobj`` to ``NULL`` and return 0.
+   If the referent is no longer live, set *\*pobj* to ``NULL`` and return 0.
 
    .. versionadded:: 3.13
 

Modules/_testcapimodule.c

@@ -3432,7 +3432,7 @@ check_weakref_capi(PyObject *self, PyObject *factory)
     PyErr_Clear();
 
     assert(PyWeakref_GetObject(invalid_weakref) == NULL);
-    assert(PyErr_ExceptionMatches(PyExc_TypeError));
+    assert(PyErr_ExceptionMatches(PyExc_SystemError));
     PyErr_Clear();
 
     Py_RETURN_NONE;

Objects/weakrefobject.c

@@ -915,14 +915,10 @@ PyWeakref_GetRef(PyObject *ref, PyObject **pobj)
 PyObject *
 PyWeakref_GetObject(PyObject *ref)
 {
-    if (ref == NULL) {
+    if (ref == NULL || !PyWeakref_Check(ref)) {
         PyErr_BadInternalCall();
         return NULL;
     }
-    if (!PyWeakref_Check(ref)) {
-        PyErr_SetString(PyExc_TypeError, "expected a weakref");
-        return NULL;
-    }
     return PyWeakref_GET_OBJECT(ref);
 }