Add Python 3.12 / 3.13 / 3.14 support

.github/workflows/main.yml

@@ -22,7 +22,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        python: ["3.8", "3.9", "3.10", "3.11"]
+        python: ["3.8", "3.9", "3.10", "3.11", "3.12", "3.13", "3.14"]
 
     steps:
       - name: Checkout code
@@ -49,7 +49,16 @@ jobs:
           echo PYTHONHOME=$(python -c 'import sys; print(sys.prefix)') >> $GITHUB_ENV
 
       - name: Embedding tests
-        run: dotnet test --runtime any-x64 --logger "console;verbosity=detailed" src/embed_tests/
+        run: dotnet test --runtime any-x64 --logger "console;verbosity=detailed" src/embed_tests/ --filter "FullyQualifiedName!~SetPythonPath"
+
+      # SetPythonPath exercises PythonEngine.PythonPath, which uses the deprecated Py_SetPath
+      # to pin a fixed module search path. CPython 3.13+ keeps that path config in _PyRuntime
+      # across Py_Finalize and provides no way to reset it back to auto-computation without the
+      # PyConfig API, so once this test runs, every later interpreter re-initialization in the
+      # same process is forced onto the pinned path and eventually fails to import encodings.
+      # Run it in its own process so it cannot pollute the rest of the suite.
+      - name: Embedding tests (SetPythonPath, isolated process)
+        run: dotnet test --runtime any-x64 --logger "console;verbosity=detailed" src/embed_tests/ --filter "FullyQualifiedName~SetPythonPath"
 
       - name: Python Tests (.NET Core)
         run: pytest --runtime netcore tests

pyproject.toml

@@ -13,7 +13,7 @@ dependencies = [
     "clr_loader>=0.2.2,<0.3.0"
 ]
 
-requires-python = ">=3.7, <3.12"
+requires-python = ">=3.7, <3.15"
 
 classifiers = [
     "Development Status :: 5 - Production/Stable",

src/embed_tests/ClassManagerTests.cs

@@ -965,7 +965,14 @@ private class TestClass2 : TestClass1
         {
             public PyObject Get(PyObject o)
             {
-                return "PyObject Get(PyObject o)".ToPython();
+                // This managed method is invoked by pythonnet with the GIL released
+                // (MethodBinder uses allow_threads around managed calls). Re-entering
+                // Python here - creating a str via ToPython() - requires re-acquiring
+                // the GIL; on CPython 3.12+ allocating without the GIL is fatal.
+                using (Py.GIL())
+                {
+                    return "PyObject Get(PyObject o)".ToPython();
+                }
             }
 
             public dynamic Get(Type t)

src/embed_tests/Codecs.cs

@@ -361,6 +361,14 @@ from datetime import datetime
         [Test]
         public void ExceptionDecodedNoInstance()
         {
+            if (Runtime.PyVersion >= new Version(3, 12))
+            {
+                // Python 3.12+ eagerly normalizes the error indicator, so an exception
+                // always reaches the decoder with an instance ("value"). The instanceless
+                // error scenario this decoder targets can no longer be produced by CPython.
+                Assert.Ignore("Instanceless exceptions are not produced on Python 3.12+ (eager normalization).");
+            }
+
             PyObjectConversions.RegisterDecoder(new InstancelessExceptionDecoder());
             using var scope = Py.CreateScope();
             var error = Assert.Throws<ValueErrorWrapper>(() => PythonEngine.Exec(