gh-118473: Fix set_asyncgen_hooks not to be partially set when arguments are invalid (#118474)

Author: youknowone

Lib/test/test_sys.py

@@ -1788,14 +1788,28 @@ def test_asyncgen_hooks(self):
         self.assertIsNone(old.finalizer)
 
         firstiter = lambda *a: None
+        finalizer = lambda *a: None
+
+        with self.assertRaises(TypeError):
+            sys.set_asyncgen_hooks(firstiter=firstiter, finalizer="invalid")
+        cur = sys.get_asyncgen_hooks()
+        self.assertIsNone(cur.firstiter)
+        self.assertIsNone(cur.finalizer)
+
+        # gh-118473
+        with self.assertRaises(TypeError):
+            sys.set_asyncgen_hooks(firstiter="invalid", finalizer=finalizer)
+        cur = sys.get_asyncgen_hooks()
+        self.assertIsNone(cur.firstiter)
+        self.assertIsNone(cur.finalizer)
+
         sys.set_asyncgen_hooks(firstiter=firstiter)
         hooks = sys.get_asyncgen_hooks()
         self.assertIs(hooks.firstiter, firstiter)
         self.assertIs(hooks[0], firstiter)
         self.assertIs(hooks.finalizer, None)
         self.assertIs(hooks[1], None)
 
-        finalizer = lambda *a: None
         sys.set_asyncgen_hooks(finalizer=finalizer)
         hooks = sys.get_asyncgen_hooks()
         self.assertIs(hooks.firstiter, firstiter)

Misc/NEWS.d/next/Core and Builtins/2024-05-01-22-43-54.gh-issue-118473.QIvq9R.rst

@@ -0,0 +1 @@
+Fix :func:`sys.set_asyncgen_hooks` not to be partially set when raising :exc:`TypeError`.

Python/sysmodule.c

@@ -1399,12 +1399,6 @@ sys_set_asyncgen_hooks(PyObject *self, PyObject *args, PyObject *kw)
                          Py_TYPE(finalizer)->tp_name);
             return NULL;
         }
-        if (_PyEval_SetAsyncGenFinalizer(finalizer) < 0) {
-            return NULL;
-        }
-    }
-    else if (finalizer == Py_None && _PyEval_SetAsyncGenFinalizer(NULL) < 0) {
-        return NULL;
     }
 
     if (firstiter && firstiter != Py_None) {
@@ -1414,15 +1408,33 @@ sys_set_asyncgen_hooks(PyObject *self, PyObject *args, PyObject *kw)
                          Py_TYPE(firstiter)->tp_name);
             return NULL;
         }
-        if (_PyEval_SetAsyncGenFirstiter(firstiter) < 0) {
+    }
+
+    PyObject *cur_finalizer = _PyEval_GetAsyncGenFinalizer();
+
+    if (finalizer && finalizer != Py_None) {
+        if (_PyEval_SetAsyncGenFinalizer(finalizer) < 0) {
             return NULL;
         }
     }
-    else if (firstiter == Py_None && _PyEval_SetAsyncGenFirstiter(NULL) < 0) {
+    else if (finalizer == Py_None && _PyEval_SetAsyncGenFinalizer(NULL) < 0) {
         return NULL;
     }
 
+    if (firstiter && firstiter != Py_None) {
+        if (_PyEval_SetAsyncGenFirstiter(firstiter) < 0) {
+            goto error;
+        }
+    }
+    else if (firstiter == Py_None && _PyEval_SetAsyncGenFirstiter(NULL) < 0) {
+        goto error;
+    }
+
     Py_RETURN_NONE;
+
+error:
+    _PyEval_SetAsyncGenFinalizer(cur_finalizer);
+    return NULL;
 }
 
 PyDoc_STRVAR(set_asyncgen_hooks_doc,