From 3b9694a8e6db8c401b8f02e021c1416023f8f90a Mon Sep 17 00:00:00 2001
From: "Miss Islington (bot)"
 <31488909+miss-islington@users.noreply.github.com>
Date: Sun, 12 Oct 2025 13:16:43 +0200
Subject: [PATCH] [3.14] gh-139988: fix a leak when failing to create a Union
 type (GH-139990) (#139993)
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gh-139988: fix a leak when failing to create a Union type (GH-139990)
(cherry picked from commit 6710156bd27dd48493d15f515506a0ead5d0328f)

Co-authored-by: Bénédikt Tran <10796600+picnixz@users.noreply.github.com>
---
 .../2025-10-12-11-00-06.gh-issue-139988.4wi51t.rst              | 2 ++
 Objects/unionobject.c                                           | 2 ++
 2 files changed, 4 insertions(+)
 create mode 100644 Misc/NEWS.d/next/Core_and_Builtins/2025-10-12-11-00-06.gh-issue-139988.4wi51t.rst

diff --git a/Misc/NEWS.d/next/Core_and_Builtins/2025-10-12-11-00-06.gh-issue-139988.4wi51t.rst b/Misc/NEWS.d/next/Core_and_Builtins/2025-10-12-11-00-06.gh-issue-139988.4wi51t.rst
new file mode 100644
index 000000000000..60fa3b1d339c
--- /dev/null
+++ b/Misc/NEWS.d/next/Core_and_Builtins/2025-10-12-11-00-06.gh-issue-139988.4wi51t.rst
@@ -0,0 +1,2 @@
+Fix a memory leak when failing to create a :class:`~typing.Union` type.
+Patch by Bénédikt Tran.
diff --git a/Objects/unionobject.c b/Objects/unionobject.c
index 2206ed80ef03..c4ece0fe09f0 100644
--- a/Objects/unionobject.c
+++ b/Objects/unionobject.c
@@ -474,11 +474,13 @@ _Py_union_from_tuple(PyObject *args)
     }
     if (PyTuple_CheckExact(args)) {
         if (!unionbuilder_add_tuple(&ub, args)) {
+            unionbuilder_finalize(&ub);
             return NULL;
         }
     }
     else {
         if (!unionbuilder_add_single(&ub, args)) {
+            unionbuilder_finalize(&ub);
             return NULL;
         }
     }
-- 
2.47.3