bpo-30524: Fix _PyStack_UnpackDict() (#1886)

* bpo-29259: Remove unused func parameter of _PyStack_UnpackDict()
* bpo-29286: Change _PyStack_UnpackDict() prototype to be able to
  notify of failure when args is NULL. _PyStack_UnpackDict() now
  returns -1 on error.

2 files changed, 11 insertions, 11 deletions

diff --git a/Objects/abstract.c b/Objects/abstract.c
index d838856..3585b34 100644
--- a/Objects/abstract.c
+++ b/Objects/abstract.c
@@ -2389,9 +2389,9 @@ _PyStack_AsDict(PyObject **values, PyObject *kwnames)
     return kwdict;
 }
 
-PyObject **
+int
 _PyStack_UnpackDict(PyObject **args, Py_ssize_t nargs, PyObject *kwargs,
-                    PyObject **p_kwnames, PyObject *func)
+                    PyObject ***p_stack, PyObject **p_kwnames)
 {
     PyObject **stack, **kwstack;
     Py_ssize_t nkwargs;
@@ -2402,27 +2402,27 @@ _PyStack_UnpackDict(PyObject **args, Py_ssize_t nargs, PyObject *kwargs,
     assert(nargs >= 0);
     assert(kwargs == NULL || PyDict_CheckExact(kwargs));
 
-    nkwargs = (kwargs != NULL) ? PyDict_Size(kwargs) : 0;
-    if (!nkwargs) {
+    if (kwargs == NULL || (nkwargs = PyDict_Size(kwargs)) == 0) {
+        *p_stack = args;
         *p_kwnames = NULL;
-        return args;
+        return 0;
     }
 
     if ((size_t)nargs > PY_SSIZE_T_MAX / sizeof(stack[0]) - (size_t)nkwargs) {
         PyErr_NoMemory();
-        return NULL;
+        return -1;
     }
 
     stack = PyMem_Malloc((nargs + nkwargs) * sizeof(stack[0]));
     if (stack == NULL) {
         PyErr_NoMemory();
-        return NULL;
+        return -1;
     }
 
     kwnames = PyTuple_New(nkwargs);
     if (kwnames == NULL) {
         PyMem_Free(stack);
-        return NULL;
+        return -1;
     }
 
     /* Copy position arguments (borrowed references) */
@@ -2441,8 +2441,9 @@ _PyStack_UnpackDict(PyObject **args, Py_ssize_t nargs, PyObject *kwargs,
         i++;
     }
 
+    *p_stack = stack;
     *p_kwnames = kwnames;
-    return stack;
+    return 0;
 }
 
 PyObject *
diff --git a/Objects/methodobject.c b/Objects/methodobject.c
index c2001f0..fe52545 100644
--- a/Objects/methodobject.c
+++ b/Objects/methodobject.c
@@ -243,8 +243,7 @@ _PyCFunction_FastCallDict(PyObject *func_obj, PyObject **args, Py_ssize_t nargs,
         PyObject *kwnames;
         _PyCFunctionFast fastmeth = (_PyCFunctionFast)meth;
 
-        stack = _PyStack_UnpackDict(args, nargs, kwargs, &kwnames, func_obj);
-        if (stack == NULL) {
+        if (_PyStack_UnpackDict(args, nargs, kwargs, &stack, &kwnames) < 0) {
             return NULL;
         }