From: Miss Islington (bot) <31488909+miss-islington@users.noreply.github.com>
Date: Sun, 12 Oct 2025 11:16:43 +0000 (+0200)
Subject: [3.14] gh-139988: fix a leak when failing to create a Union type (GH-139990) (#139993)
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=3b9694a8e6db8c401b8f02e021c1416023f8f90a;p=thirdparty%2FPython%2Fcpython.git

[3.14] gh-139988: fix a leak when failing to create a Union type (GH-139990) (#139993)

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>
---

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;
         }
     }