Backport 43022:

Fix and test (manually w/xx module) passing NULLs to PyObject_Str() and
PyObject_Unicode().  This problem was originally reported from Coverity
and addresses mail on python-dev "checkin r43015".

This inlines the conversion of the string to unicode and cleans
up/simplifies some code at the end of the PyObject_Unicode().

We really need a complete C API test module for all public APIs
and passing good and bad parameter values.

diff --git a/Modules/xxmodule.c b/Modules/xxmodule.c
index 5f75b6cf8f9de6d6064b67f4ac9fd5ff8d10ffd0..44e5e09ff95fbfe959ffd0dab8bad51e6391c85f 100644 (file)
--- a/Modules/xxmodule.c
+++ b/Modules/xxmodule.c
@@ -197,6 +197,18 @@ xx_bug(PyObject *self, PyObject *args)
        return Py_None;
 }
 
+/* Example passing NULLs to PyObject_Str(NULL) and PyObject_Unicode(NULL). */
+
+static PyObject *
+xx_null(PyObject *self, PyObject *noargs)
+{
+       PyObject *o1 = PyObject_Str(NULL), *o2 = PyObject_Unicode(NULL);
+       PyObject *tuple = PyTuple_Pack(2, o1, o2);
+       Py_XDECREF(o1);
+       Py_XDECREF(o2);
+       return tuple;
+}
+
 /* Test bad format character */
 
 static PyObject *
@@ -331,6 +343,8 @@ static PyMethodDef xx_methods[] = {
                PyDoc_STR("new() -> new Xx object")},
        {"bug",         xx_bug,         METH_VARARGS,
                PyDoc_STR("bug(o) -> None")},
+       {"null",        xx_null,        METH_NOARGS,
+               PyDoc_STR("null(o) -> ('NULL', u'NULL')")},
        {NULL,          NULL}           /* sentinel */
 };
 

diff --git a/Objects/object.c b/Objects/object.c
index 87aa475a60928b5204524fbdc53314cd78dace3f..7dbd554dffc467c32e2858dac8e6be93925b98e0 100644 (file)
--- a/Objects/object.c
+++ b/Objects/object.c
@@ -373,9 +373,15 @@ PyObject *
 PyObject_Unicode(PyObject *v)
 {
        PyObject *res;
+       PyObject *str;
 
        if (v == NULL) {
                res = PyString_FromString("<NULL>");
+               if (res == NULL)
+                       return NULL;
+               str = PyUnicode_FromEncodedObject(res, NULL, "strict");
+               Py_DECREF(res);
+               return str;
        } else if (PyUnicode_CheckExact(v)) {
                Py_INCREF(v);
                return v;
@@ -418,13 +424,9 @@ PyObject_Unicode(PyObject *v)
        if (res == NULL)
                return NULL;
        if (!PyUnicode_Check(res)) {
-               PyObject *str;
                str = PyUnicode_FromEncodedObject(res, NULL, "strict");
                Py_DECREF(res);
-               if (str)
-                       res = str;
-               else
-                       return NULL;
+               res = str;
        }
        return res;
 }