Run CI for Python 3.14 free-threading (#20029)

Author: cdce8p

.github/workflows/test.yml

@@ -59,6 +59,12 @@ jobs:
           toxenv: py
           tox_extra_args: "-n 4"
           test_mypyc: true
+        - name: Test suite with py314t-ubuntu, mypyc-compiled
+          python: '3.14t'
+          os: ubuntu-24.04-arm
+          toxenv: py
+          tox_extra_args: "-n 4"
+          test_mypyc: true
         - name: Test suite with py314-windows-64
           python: '3.14'
           os: windows-latest

mypy/report.py

@@ -8,6 +8,7 @@
 import os
 import shutil
 import sys
+import sysconfig
 import time
 import tokenize
 from abc import ABCMeta, abstractmethod
@@ -25,9 +26,13 @@
 from mypy.version import __version__
 
 try:
-    from lxml import etree  # type: ignore[import-untyped]
+    if sys.version_info >= (3, 14) and bool(sysconfig.get_config_var("Py_GIL_DISABLED")):
+        # lxml doesn't support free-threading yet
+        LXML_INSTALLED = False
+    else:
+        from lxml import etree  # type: ignore[import-untyped]
 
-    LXML_INSTALLED = True
+        LXML_INSTALLED = True
 except ImportError:
     LXML_INSTALLED = False
 

mypy/test/testcheck.py

@@ -5,6 +5,7 @@
 import os
 import re
 import sys
+import sysconfig
 import tempfile
 from pathlib import Path
 
@@ -27,7 +28,11 @@
 from mypy.test.update_data import update_testcase_output
 
 try:
-    import lxml  # type: ignore[import-untyped]
+    if sys.version_info >= (3, 14) and bool(sysconfig.get_config_var("Py_GIL_DISABLED")):
+        # lxml doesn't support free-threading yet
+        lxml = None
+    else:
+        import lxml  # type: ignore[import-untyped]
 except ImportError:
     lxml = None
 

mypy/test/testcmdline.py

@@ -10,6 +10,7 @@
 import re
 import subprocess
 import sys
+import sysconfig
 
 from mypy.test.config import PREFIX, test_temp_dir
 from mypy.test.data import DataDrivenTestCase, DataSuite
@@ -20,7 +21,11 @@
 )
 
 try:
-    import lxml  # type: ignore[import-untyped]
+    if sys.version_info >= (3, 14) and bool(sysconfig.get_config_var("Py_GIL_DISABLED")):
+        # lxml doesn't support free-threading yet
+        lxml = None
+    else:
+        import lxml  # type: ignore[import-untyped]
 except ImportError:
     lxml = None
 

mypy/test/testreports.py

@@ -2,13 +2,19 @@
 
 from __future__ import annotations
 
+import sys
+import sysconfig
 import textwrap
 
 from mypy.report import CoberturaPackage, get_line_rate
 from mypy.test.helpers import Suite, assert_equal
 
 try:
-    import lxml  # type: ignore[import-untyped]
+    if sys.version_info >= (3, 14) and bool(sysconfig.get_config_var("Py_GIL_DISABLED")):
+        # lxml doesn't support free-threading yet
+        lxml = None
+    else:
+        import lxml  # type: ignore[import-untyped]
 except ImportError:
     lxml = None