pythongh-105375: Improve errnomodule error handling (python#105590)

Bail immediately if an exception is set, to prevent exceptions from being overwritten.
Incred · Jun 9, 2023 · eede1d2 · eede1d2
1 parent 89aac6f
commit eede1d2
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Showing 2 changed files with 6 additions and 3 deletions.
diff --git a/Misc/NEWS.d/next/Library/2023-06-09-21-04-39.gh-issue-105375.bTcqS9.rst b/Misc/NEWS.d/next/Library/2023-06-09-21-04-39.gh-issue-105375.bTcqS9.rst
@@ -0,0 +1 @@
+Fix bugs in :mod:`pickle` where exceptions could be overwritten.
diff --git a/Modules/errnomodule.c b/Modules/errnomodule.c
@@ -81,10 +81,12 @@ _add_errcode(PyObject *module_dict, PyObject *error_dict, const char *name_str,
 static int
 errno_exec(PyObject *module)
 {
-    PyObject *module_dict = PyModule_GetDict(module);
+    PyObject *module_dict = PyModule_GetDict(module);  // Borrowed ref.
+    if (module_dict == NULL) {
+        return -1;
+    }
     PyObject *error_dict = PyDict_New();
-    if (!module_dict || !error_dict) {
-        Py_XDECREF(error_dict);
+    if (error_dict == NULL) {
         return -1;
     }
     if (PyDict_SetItemString(module_dict, "errorcode", error_dict) < 0) {