PyUnicodeWriter_WriteRepr(NULL) now writes "<NULL>" (#170)

vstinner · web-flow · commit 75a796764d63 · 2026-03-19T12:10:30.000+01:00
diff --git a/docs/api.rst b/docs/api.rst
@@ -262,6 +262,7 @@ Not supported:
 * ``PyInitConfig_SetStrList()``
 * ``PyType_GetBaseByToken()``
 * ``PyUnicodeWriter_DecodeUTF8Stateful()``
+* ``PyUnicodeWriter_WriteUCS4()``
 * ``Py_InitializeFromInitConfig()``
 
 
diff --git a/pythoncapi_compat.h b/pythoncapi_compat.h
@@ -1425,6 +1425,11 @@ PyUnicodeWriter_WriteStr(PyUnicodeWriter *writer, PyObject *obj)
 static inline int
 PyUnicodeWriter_WriteRepr(PyUnicodeWriter *writer, PyObject *obj)
 {
+    if (obj == NULL) {
+        return _PyUnicodeWriter_WriteASCIIString((_PyUnicodeWriter*)writer,
+                                                 "<NULL>", 6);
+    }
+
     PyObject *str = PyObject_Repr(obj);
     if (str == NULL) {
         return -1;
diff --git a/tests/test_pythoncapi_compat_cext.c b/tests/test_pythoncapi_compat_cext.c
@@ -1908,13 +1908,17 @@ test_unicodewriter(PyObject *Py_UNUSED(self), PyObject *Py_UNUSED(args))
         goto error;
     }
     Py_CLEAR(str);
+    if (PyUnicodeWriter_WriteRepr(writer, NULL) < 0) {
+        goto error;
+    }
 
     {
         PyObject *result = PyUnicodeWriter_Finish(writer);
         if (result == NULL) {
             return NULL;
         }
-        assert(PyUnicode_EqualToUTF8(result, "var=long non-ASCII valu\xC3\xA9 'repr'"));
+        const char *expected = "var=long non-ASCII valu\xC3\xA9 'repr'<NULL>";
+        assert(PyUnicode_EqualToUTF8(result, expected));
         Py_DECREF(result);
     }
 

Original file line number	Diff line number	Diff line change
`@@ -1908,13 +1908,17 @@ test_unicodewriter(PyObject Py_UNUSED(self), PyObject Py_UNUSED(args))`
`1908`	`1908`	`goto error;`
`1909`	`1909`	`}`
`1910`	`1910`	`Py_CLEAR(str);`
	`1911`	`+ if (PyUnicodeWriter_WriteRepr(writer, NULL) < 0) {`
	`1912`	`+ goto error;`
	`1913`	`+ }`
`1911`	`1914`
`1912`	`1915`	`{`
`1913`	`1916`	`PyObject *result = PyUnicodeWriter_Finish(writer);`
`1914`	`1917`	`if (result == NULL) {`
`1915`	`1918`	`return NULL;`
`1916`	`1919`	`}`
`1917`		`- assert(PyUnicode_EqualToUTF8(result, "var=long non-ASCII valu\xC3\xA9 'repr'"));`
	`1920`	`+ const char *expected = "var=long non-ASCII valu\xC3\xA9 'repr'<NULL>";`
	`1921`	`+ assert(PyUnicode_EqualToUTF8(result, expected));`
`1918`	`1922`	`Py_DECREF(result);`
`1919`	`1923`	`}`
`1920`	`1924`