[Python-checkins] [3.11] gh-105375: Improve error handling in `zoneinfo` module (GH-105586) (#105613)

[erlend-aasland]

https://github.com/python/cpython/commit/4ceb5c4924f8a63ddb45aac001565bb36cf94c1e
commit: 4ceb5c4924f8a63ddb45aac001565bb36cf94c1e
branch: 3.11
author: Miss Islington (bot) <31488909+miss-islington at users.noreply.github.com>
committer: erlend-aasland <erlend.aasland at protonmail.com>
date: 2023-06-09T22:54:00Z
summary:

[3.11] gh-105375: Improve error handling in `zoneinfo` module (GH-105586) (#105613)

Fix bugs where exceptions could end up being overwritten
because of deferred error handling.

(cherry picked from commit 33c92c4f15539806c8aff8574ff30a8b307e3e4d)

Co-authored-by: Nikita Sobolev <mail at sobolevn.me>
Co-authored-by: Erlend E. Aasland <erlend.aasland at protonmail.com>

files:
A Misc/NEWS.d/next/Library/2023-06-09-21-11-28.gh-issue-105375.4Mxn7t.rst
M Modules/_zoneinfo.c

diff --git a/Misc/NEWS.d/next/Library/2023-06-09-21-11-28.gh-issue-105375.4Mxn7t.rst b/Misc/NEWS.d/next/Library/2023-06-09-21-11-28.gh-issue-105375.4Mxn7t.rst
new file mode 100644
index 000000000000..4202b758d1db
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2023-06-09-21-11-28.gh-issue-105375.4Mxn7t.rst
@@ -0,0 +1 @@
+Fix bugs in :mod:`zoneinfo` where exceptions could be overwritten.
diff --git a/Modules/_zoneinfo.c b/Modules/_zoneinfo.c
index 55975f4e2691..5f584ff93e9a 100644
--- a/Modules/_zoneinfo.c
+++ b/Modules/_zoneinfo.c
@@ -581,14 +581,19 @@ zoneinfo_fromutc(PyObject *obj_self, PyObject *dt)
         }
         else {
             PyObject *replace = PyObject_GetAttrString(tmp, "replace");
+            Py_DECREF(tmp);
+            if (replace == NULL) {
+                return NULL;
+            }
             PyObject *args = PyTuple_New(0);
+            if (args == NULL) {
+                Py_DECREF(replace);
+                return NULL;
+            }
             PyObject *kwargs = PyDict_New();
-
-            Py_DECREF(tmp);
-            if (args == NULL || kwargs == NULL || replace == NULL) {
-                Py_XDECREF(args);
-                Py_XDECREF(kwargs);
-                Py_XDECREF(replace);
+            if (kwargs == NULL) {
+                Py_DECREF(replace);
+                Py_DECREF(args);
                 return NULL;
             }