From 1b2a5485f94ccbe43a45eb9990a5649ae3d2499e Mon Sep 17 00:00:00 2001
From: Victor Stinner <vstinner@python.org>
Date: Thu, 10 Oct 2024 01:32:02 +0200
Subject: [PATCH] gh-125196: PyUnicodeWriter_Discard(NULL) does nothing
 (#125222)

---
 Doc/c-api/unicode.rst   | 2 ++
 Objects/listobject.c    | 4 +---
 Objects/unicodeobject.c | 3 +++
 3 files changed, 6 insertions(+), 3 deletions(-)

diff --git a/Doc/c-api/unicode.rst b/Doc/c-api/unicode.rst
index f5704cffa19..4daf9e9fdbf 100644
--- a/Doc/c-api/unicode.rst
+++ b/Doc/c-api/unicode.rst
@@ -1600,6 +1600,8 @@ object.
 
    Discard the internal Unicode buffer and destroy the writer instance.
 
+   If *writer* is ``NULL``, no operation is performed.
+
 .. c:function:: int PyUnicodeWriter_WriteChar(PyUnicodeWriter *writer, Py_UCS4 ch)
 
    Write the single Unicode character *ch* into *writer*.
diff --git a/Objects/listobject.c b/Objects/listobject.c
index e7090f20001..930aefde325 100644
--- a/Objects/listobject.c
+++ b/Objects/listobject.c
@@ -563,9 +563,7 @@ list_repr_impl(PyListObject *v)
     return PyUnicodeWriter_Finish(writer);
 
 error:
-    if (writer != NULL) {
-        PyUnicodeWriter_Discard(writer);
-    }
+    PyUnicodeWriter_Discard(writer);
     Py_ReprLeave((PyObject *)v);
     return NULL;
 }
diff --git a/Objects/unicodeobject.c b/Objects/unicodeobject.c
index a9b33248163..93c1025b6a3 100644
--- a/Objects/unicodeobject.c
+++ b/Objects/unicodeobject.c
@@ -13455,6 +13455,9 @@ PyUnicodeWriter_Create(Py_ssize_t length)
 
 void PyUnicodeWriter_Discard(PyUnicodeWriter *writer)
 {
+    if (writer == NULL) {
+        return;
+    }
     _PyUnicodeWriter_Dealloc((_PyUnicodeWriter*)writer);
     PyMem_Free(writer);
 }