From 7202c3af81c208521524389fcf374fd73211b51b Mon Sep 17 00:00:00 2001
From: Ran Benita <ran@unusedvar.com>
Date: Wed, 27 May 2026 11:03:05 +0300
Subject: [PATCH 1/3] testing: fix `test_dont_write_bytecode` for Python 3.15

Python 3.15b1 no longer sets `module.__cached__`. But
`module.__spec__.cached` is still set, is recommended over
`module.__cached__` by Python documentation, and it works for all
previous versions as well, so switch to that.

Ref:
https://docs.python.org/3.15/reference/datamodel.html#module.__file__
---
 testing/test_assertrewrite.py | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/testing/test_assertrewrite.py b/testing/test_assertrewrite.py
index 2668001af65..e11863547ba 100644
--- a/testing/test_assertrewrite.py
+++ b/testing/test_assertrewrite.py
@@ -1082,9 +1082,10 @@ def test_dont_write_bytecode(self, pytester: Pytester, monkeypatch) -> None:
             """
             import os
             def test_no_bytecode():
-                assert "__pycache__" in __cached__
-                assert not os.path.exists(__cached__)
-                assert not os.path.exists(os.path.dirname(__cached__))"""
+                assert "__pycache__" in __spec__.cached
+                assert not os.path.exists(__spec__.cached)
+                assert not os.path.exists(os.path.dirname(__spec__.cached))
+            """
         )
         monkeypatch.setenv("PYTHONDONTWRITEBYTECODE", "1")
         assert pytester.runpytest_subprocess().ret == 0

From 15427697a510c163313c04a19ab2a5ea8cc2dcf8 Mon Sep 17 00:00:00 2001
From: Ran Benita <ran@unusedvar.com>
Date: Wed, 27 May 2026 11:18:02 +0300
Subject: [PATCH 2/3] testing: ignore "forkpty" deprecation errors coming from
 pexpect on Python 3.15

Nothing we can do about it, needs a new pexpect release, so ignore for
now.
---
 pyproject.toml | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/pyproject.toml b/pyproject.toml
index 886c968e8ee..e588c6d19d2 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -415,6 +415,8 @@ filterwarnings = [
     # https://github.com/pytest-dev/pytest/issues/2366
     # https://github.com/pytest-dev/pytest/pull/13057
     'default::pytest.PytestFDWarning',
+    # https://github.com/pexpect/pexpect/issues/827
+    'ignore:.*use of forkpty\(\) may lead to deadlocks in the child:DeprecationWarning:ptyprocess.*',
 ]
 pytester_example_dir = "testing/example_scripts"
 markers = [

From 3cd19882adacc6baeb5374f6c416962768a92ca0 Mon Sep 17 00:00:00 2001
From: Ran Benita <ran@unusedvar.com>
Date: Wed, 27 May 2026 11:10:31 +0300
Subject: [PATCH 3/3] Add official support for Python 3.15

Currently at beta 1.

Fix #14524.
---
 .github/workflows/test.yml      | 19 +++++++++++++++++++
 changelog/14524.improvement.rst |  1 +
 pyproject.toml                  |  3 ++-
 tox.ini                         |  1 +
 4 files changed, 23 insertions(+), 1 deletion(-)
 create mode 100644 changelog/14524.improvement.rst

diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index a42b59e5722..e70be0ab309 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -65,6 +65,7 @@ jobs:
           "windows-py312",
           "windows-py313",
           "windows-py314",
+          "windows-py315",
 
           "ubuntu-py310-unittest-asynctest",
           "ubuntu-py310-unittest-twisted24",
@@ -77,12 +78,14 @@ jobs:
           "ubuntu-py312",
           "ubuntu-py313-pexpect",
           "ubuntu-py314",
+          "ubuntu-py315",
           "ubuntu-pypy3-xdist",
 
           "macos-py310",
           "macos-py312",
           "macos-py313",
           "macos-py314",
+          "macos-py315",
 
           "doctesting",
           "plugins",
@@ -141,6 +144,11 @@ jobs:
             tox_env: "py314"
             use_coverage: true
 
+          - name: "windows-py315"
+            python: "3.15"
+            os: windows-latest
+            tox_env: "py315"
+
           # Use separate jobs for different unittest flavors (twisted, asynctest) to ensure proper coverage.
           - name: "ubuntu-py310-unittest-asynctest"
             python: "3.10"
@@ -208,6 +216,12 @@ jobs:
             tox_env: "py314"
             use_coverage: true
 
+          - name: "ubuntu-py315"
+            python: "3.15"
+            os: ubuntu-latest
+            tox_env: "py315"
+            use_coverage: true
+
           - name: "ubuntu-pypy3-xdist"
             python: "pypy-3.10"
             os: ubuntu-latest
@@ -236,6 +250,11 @@ jobs:
             os: macos-latest
             tox_env: "py314-xdist"
 
+          - name: "macos-py315"
+            python: "3.15"
+            os: macos-latest
+            tox_env: "py315-xdist"
+
           - name: "plugins"
             python: "3.12"
             os: ubuntu-latest
diff --git a/changelog/14524.improvement.rst b/changelog/14524.improvement.rst
new file mode 100644
index 00000000000..e6b7c996077
--- /dev/null
+++ b/changelog/14524.improvement.rst
@@ -0,0 +1 @@
+Add official Python 3.15 support.
diff --git a/pyproject.toml b/pyproject.toml
index e588c6d19d2..cce08575ce1 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -38,6 +38,7 @@ classifiers = [
     "Programming Language :: Python :: 3.12",
     "Programming Language :: Python :: 3.13",
     "Programming Language :: Python :: 3.14",
+    "Programming Language :: Python :: 3.15",
     "Topic :: Software Development :: Libraries",
     "Topic :: Software Development :: Testing",
     "Topic :: Utilities",
@@ -353,7 +354,7 @@ ignore = "W009"
 
 [tool.pyproject-fmt]
 indent = 4
-max_supported_python = "3.14"
+max_supported_python = "3.15"
 
 [tool.pytest]
 minversion = "2.0"
diff --git a/tox.ini b/tox.ini
index 515313a9bf6..b37bdb6aa85 100644
--- a/tox.ini
+++ b/tox.ini
@@ -8,6 +8,7 @@ envlist =
     py312
     py313
     py314
+    py315
     pypy3
     py310-{pexpect,xdist,twisted24,twisted25,asynctest,numpy,pluggymain,pylib}
     doctesting