gh-102471: Change PyLongWriter_Discard(NULL) to do nothing (#129339)

It's convenient to be able to call PyLongWriter_Discard(NULL) in
error handling code.

diff --git a/Doc/c-api/long.rst b/Doc/c-api/long.rst
index 084ba513493ffec8524c4b1aeadc4792a42454db..25d9e62e3872797b87d0755fc4e21a4da564f7d6 100644 (file)
--- a/Doc/c-api/long.rst
+++ b/Doc/c-api/long.rst
@@ -824,6 +824,6 @@ The :c:type:`PyLongWriter` API can be used to import an integer.
 
    Discard a :c:type:`PyLongWriter` created by :c:func:`PyLongWriter_Create`.
 
-   *writer* must not be ``NULL``.
+   If *writer* is ``NULL``, no operation is performed.
 
    The writer instance and the *digits* array are invalid after the call.

diff --git a/Objects/longobject.c b/Objects/longobject.c
index 905c4695f60d4f3980440d7ead9836d1a8899458..43be1ab056e0fe98b6f5efed55225bf03d327d73 100644 (file)
--- a/Objects/longobject.c
+++ b/Objects/longobject.c
@@ -6953,6 +6953,10 @@ error:
 void
 PyLongWriter_Discard(PyLongWriter *writer)
 {
+    if (writer == NULL) {
+        return;
+    }
+
     PyLongObject *obj = (PyLongObject *)writer;
     assert(Py_REFCNT(obj) == 1);
     Py_DECREF(obj);