Add free-threaded python to CI including multithreading test

.github/workflows/ci.yml

@@ -6,7 +6,7 @@ jobs:
       fail-fast: false
       matrix:
         os: ["ubuntu-latest"]
-        python-version: ["3.8", "3.9", "3.10", "3.11", "3.12", "3.13", "3.14"]
+        python-version: ["3.8", "3.9", "3.10", "3.11", "3.12", "3.13", "3.14", "3.14t"]
         include:
           - os: macos-latest
             python-version: "3.x"

test/python_magic_test.py

@@ -10,6 +10,12 @@
 
 import pytest
 
+try:
+    from concurrent.futures import ThreadPoolExecutor
+    HAS_CONCURRENT_FUTURES = True
+except ImportError:  # python 2.7
+    HAS_CONCURRENT_FUTURES = False
+
 # for output which reports a local time
 os.environ["TZ"] = "GMT"
 
@@ -321,6 +327,25 @@ def test_symlink(self):
 
             self.assertRaises(IOError, m_follow.from_file, tmp_broken)
 
+    @unittest.skipIf(not HAS_CONCURRENT_FUTURES, "concurrent.futures not available in Python 2.7")
+    def test_thread_safety(self):
+        """Test that concurrent from_file calls don't crash (would SEGV without global lock)"""
+        filename = os.path.join(self.TESTDATA_DIR, "test.pdf")
+
+        m = magic.Magic(mime=True)
+
+        def check_file(_):
+            result = m.from_file(filename)
+            self.assertEqual(result, "application/pdf")
+            return result
+
+        with ThreadPoolExecutor(100) as executor:
+            results = list(executor.map(check_file, range(100)))
+
+        # All calls should complete successfully
+        self.assertEqual(len(results), 100)
+        self.assertTrue(all(r == "application/pdf" for r in results))
+
 
 if __name__ == "__main__":
     unittest.main()

tox.ini

@@ -10,6 +10,8 @@ envlist =
     py311,
     py312,
     py313,
+    py314,
+    py314t,
     mypy
 
 [testenv]