From 80ab33da45f25e880baefc3abfd0ebdf078b26bb Mon Sep 17 00:00:00 2001
From: Stan Ulbrych <stan@python.org>
Date: Thu, 25 Jun 2026 10:12:06 +0100
Subject: [PATCH 1/3] Skip `test_abstractmethod_integration` on free-threading

---
 Lib/test/test_abc.py | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/Lib/test/test_abc.py b/Lib/test/test_abc.py
index 59a45a2eda07b00..0956f39fd4a5d13 100644
--- a/Lib/test/test_abc.py
+++ b/Lib/test/test_abc.py
@@ -11,7 +11,7 @@
 import abc
 import _py_abc
 from inspect import isabstract
-from test.support import warnings_helper
+from test.support import requires_gil_enabled, warnings_helper
 
 def test_factory(abc_ABCMeta, abc_get_cache_token):
     class TestLegacyAPI(unittest.TestCase):
@@ -198,6 +198,7 @@ def method_two(self):
             msg = r"class C without an implementation for abstract methods 'method_one', 'method_two'"
             self.assertRaisesRegex(TypeError, msg, C)
 
+        @requires_gil_enabled()
         @warnings_helper.ignore_warnings(category=DeprecationWarning)
         def test_abstractmethod_integration(self):
             for abstractthing in [abc.abstractmethod, abc.abstractproperty,

From d2782d5567267bafe43471a67e710edcdf37a157 Mon Sep 17 00:00:00 2001
From: Stan Ulbrych <stan@python.org>
Date: Thu, 25 Jun 2026 11:05:36 +0100
Subject: [PATCH 2/3] Revert "Skip `test_abstractmethod_integration` on
 free-threading"

This reverts commit 80ab33da45f25e880baefc3abfd0ebdf078b26bb.
---
 Lib/test/test_abc.py | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/Lib/test/test_abc.py b/Lib/test/test_abc.py
index 0956f39fd4a5d13..59a45a2eda07b00 100644
--- a/Lib/test/test_abc.py
+++ b/Lib/test/test_abc.py
@@ -11,7 +11,7 @@
 import abc
 import _py_abc
 from inspect import isabstract
-from test.support import requires_gil_enabled, warnings_helper
+from test.support import warnings_helper
 
 def test_factory(abc_ABCMeta, abc_get_cache_token):
     class TestLegacyAPI(unittest.TestCase):
@@ -198,7 +198,6 @@ def method_two(self):
             msg = r"class C without an implementation for abstract methods 'method_one', 'method_two'"
             self.assertRaisesRegex(TypeError, msg, C)
 
-        @requires_gil_enabled()
         @warnings_helper.ignore_warnings(category=DeprecationWarning)
         def test_abstractmethod_integration(self):
             for abstractthing in [abc.abstractmethod, abc.abstractproperty,

From 24e9fce207a819317f99bd3206f700388b4a3361 Mon Sep 17 00:00:00 2001
From: Stan Ulbrych <stan@python.org>
Date: Thu, 25 Jun 2026 11:07:16 +0100
Subject: [PATCH 3/3] Allow the job to fail instead

---
 .github/workflows/build.yml | 14 +++++++++++++-
 1 file changed, 13 insertions(+), 1 deletion(-)

diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index d9a956a6bf53038..f54692e9b4e4c02 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -558,7 +558,6 @@ jobs:
         - Thread
         free-threading:
         - false
-        - true
         sanitizer:
         - TSan
         include:
@@ -570,6 +569,17 @@ jobs:
       sanitizer: ${{ matrix.sanitizer }}
       free-threading: ${{ matrix.free-threading }}
 
+  # XXX: Temporarily allow this job to fail to not block PRs.
+  build-san-free-threading:
+    # ${{ '' } is a hack to nest jobs under the same sidebar category.
+    name: Sanitizers${{ '' }}  # zizmor: ignore[obfuscation]
+    needs: build-context
+    if: needs.build-context.outputs.run-ubuntu == 'true'
+    uses: ./.github/workflows/reusable-san.yml
+    with:
+      sanitizer: TSan
+      free-threading: true
+
   cross-build-linux:
     name: Cross build Linux
     runs-on: ubuntu-latest
@@ -673,6 +683,7 @@ jobs:
     - test-hypothesis
     - build-asan
     - build-san
+    - build-san-free-threading
     - cross-build-linux
     - cifuzz
     if: always()
@@ -684,6 +695,7 @@ jobs:
         allowed-failures: >-
           build-android,
           build-emscripten,
+          build-san-free-threading,
           build-windows-msi,
           build-ubuntu-ssltests,
           test-hypothesis,