Fix starting the server for Python 3.14 and run tests with that version

.github/workflows/test-linux.yml

@@ -24,7 +24,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        PYTHON_VERSION: ['3.11', '3.10', '3.9']
+        PYTHON_VERSION: ['3.14', '3.13', '3.12', '3.11', '3.10', '3.9']
     timeout-minutes: 10
     steps:
       - uses: actions/cache@v4

.github/workflows/test-mac.yml

@@ -24,7 +24,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        PYTHON_VERSION: ['3.11', '3.10', '3.9']
+        PYTHON_VERSION: ['3.14', '3.12', '3.9']
     timeout-minutes: 10
     steps:
       - uses: actions/cache@v4

.github/workflows/test-win.yml

@@ -24,7 +24,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        PYTHON_VERSION: ['3.11', '3.10', '3.9']
+        PYTHON_VERSION: ['3.14', '3.12', '3.9']
     timeout-minutes: 10
     steps:
       - uses: actions/cache@v4

pylsp/python_lsp.py

@@ -4,6 +4,7 @@
 import logging
 import os
 import socketserver
+import sys
 import threading
 import uuid
 from functools import partial
@@ -71,9 +72,13 @@ def shutdown_server(check_parent_process, *args):
         handler_class.__name__ + "Handler",
         (_StreamHandlerWrapper,),
         {
-            "DELEGATE_CLASS": partial(
-                handler_class, check_parent_process=check_parent_process
-            ),
+            # We need to wrap this in staticmethod due to the changes to
+            # functools.partial in Python 3.14+
+            "DELEGATE_CLASS": staticmethod(
+                partial(handler_class, check_parent_process=check_parent_process)
+            )
+            if sys.version_info >= (3, 14)
+            else partial(handler_class, check_parent_process=check_parent_process),
             "SHUTDOWN_CALL": partial(shutdown_server, check_parent_process),
         },
     )

test/plugins/test_flake8_lint.py

@@ -126,7 +126,7 @@ def test_flake8_config_param(workspace) -> None:
     with patch("pylsp.plugins.flake8_lint.Popen") as popen_mock:
         mock_instance = popen_mock.return_value
         mock_instance.communicate.return_value = [b"", b""]
-        flake8_conf = "/tmp/some.cfg"
+        flake8_conf = "C:\\some.cfg" if os.name == "nt" else "/tmp/some.cfg"
         workspace._config.update({"plugins": {"flake8": {"config": flake8_conf}}})
         _name, doc = temp_document(DOC, workspace)
         flake8_lint.pylsp_lint(workspace, doc)