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Merge pull request pythonnet#692 from amos402/pyobject-finalizer
PyObject finalizer
2 parents 5ee234a + 4eff81e commit f83c884

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+903
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‎CHANGELOG.md

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@@ -21,10 +21,12 @@ This document follows the conventions laid out in [Keep a CHANGELOG][].
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- Catches exceptions thrown in C# iterators (yield returns) and rethrows them in python ([#475][i475])([#693][p693])
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- Implemented GetDynamicMemberNames() for PyObject to allow dynamic object members to be visible in the debugger ([#443][i443])([#690][p690])
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- Incorporated reference-style links to issues and pull requests in the CHANGELOG ([#608][i608])
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- Added PyObject finalizer support, Python objects referred by C# can be auto collect now ([#692][p692]).
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- Added detailed comments about aproaches and dangers to handle multi-app-domains ([#625][p625])
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- Python 3.7 support, builds and testing added. Defaults changed from Python 3.6 to 3.7 ([#698][p698])
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### Changed
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- PythonException included C# call stack
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- Reattach python exception traceback information (#545)
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- PythonEngine.Intialize will now call `Py_InitializeEx` with a default value of 0, so signals will not be configured by default on embedding. This is different from the previous behaviour, where `Py_Initialize` was called instead, which sets initSigs to 1. ([#449][i449])

‎src/embed_tests/Python.EmbeddingTest.csproj

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<Compile Include="TestCustomMarshal.cs" />
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<Compile Include="TestDomainReload.cs" />
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<Compile Include="TestExample.cs" />
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<Compile Include="TestFinalizer.cs" />
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<Compile Include="TestPyAnsiString.cs" />
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<Compile Include="TestPyFloat.cs" />
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<Compile Include="TestPyInt.cs" />

‎src/embed_tests/TestFinalizer.cs

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using NUnit.Framework;
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using Python.Runtime;
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using System;
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using System.Linq;
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using System.Threading;
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namespace Python.EmbeddingTest
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{
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public class TestFinalizer
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{
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private int _oldThreshold;
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[SetUp]
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public void SetUp()
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{
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_oldThreshold = Finalizer.Instance.Threshold;
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PythonEngine.Initialize();
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Exceptions.Clear();
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}
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[TearDown]
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public void TearDown()
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{
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Finalizer.Instance.Threshold = _oldThreshold;
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PythonEngine.Shutdown();
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}
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private static void FullGCCollect()
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{
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GC.Collect(GC.MaxGeneration, GCCollectionMode.Forced);
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GC.WaitForPendingFinalizers();
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}
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[Test]
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public void CollectBasicObject()
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{
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Assert.IsTrue(Finalizer.Instance.Enable);
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int thId = Thread.CurrentThread.ManagedThreadId;
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Finalizer.Instance.Threshold = 1;
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bool called = false;
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EventHandler<Finalizer.CollectArgs> handler = (s, e) =>
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{
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Assert.AreEqual(thId, Thread.CurrentThread.ManagedThreadId);
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Assert.GreaterOrEqual(e.ObjectCount, 1);
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called = true;
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};
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WeakReference shortWeak;
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WeakReference longWeak;
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{
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MakeAGarbage(out shortWeak, out longWeak);
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}
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FullGCCollect();
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// The object has been resurrected
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Assert.IsFalse(shortWeak.IsAlive);
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Assert.IsTrue(longWeak.IsAlive);
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{
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var garbage = Finalizer.Instance.GetCollectedObjects();
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Assert.NotZero(garbage.Count);
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Assert.IsTrue(garbage.Any(T => ReferenceEquals(T.Target, longWeak.Target)));
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}
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Assert.IsFalse(called);
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Finalizer.Instance.CollectOnce += handler;
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try
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{
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Finalizer.Instance.CallPendingFinalizers();
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}
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finally
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{
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Finalizer.Instance.CollectOnce -= handler;
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}
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Assert.IsTrue(called);
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}
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private static void MakeAGarbage(out WeakReference shortWeak, out WeakReference longWeak)
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{
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PyLong obj = new PyLong(1024);
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shortWeak = new WeakReference(obj);
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longWeak = new WeakReference(obj, true);
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obj = null;
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}
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private static long CompareWithFinalizerOn(PyObject pyCollect, bool enbale)
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{
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// Must larger than 512 bytes make sure Python use
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string str = new string('1', 1024);
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Finalizer.Instance.Enable = true;
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FullGCCollect();
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FullGCCollect();
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pyCollect.Invoke();
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Finalizer.Instance.Collect();
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Finalizer.Instance.Enable = enbale;
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// Estimate unmanaged memory size
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long before = Environment.WorkingSet - GC.GetTotalMemory(true);
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for (int i = 0; i < 10000; i++)
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{
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// Memory will leak when disable Finalizer
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new PyString(str);
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}
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FullGCCollect();
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FullGCCollect();
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pyCollect.Invoke();
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if (enbale)
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{
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Finalizer.Instance.Collect();
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}
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FullGCCollect();
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FullGCCollect();
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long after = Environment.WorkingSet - GC.GetTotalMemory(true);
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return after - before;
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}
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/// <summary>
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/// Because of two vms both have their memory manager,
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/// this test only prove the finalizer has take effect.
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/// </summary>
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[Test]
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[Ignore("Too many uncertainties, only manual on when debugging")]
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public void SimpleTestMemory()
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{
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bool oldState = Finalizer.Instance.Enable;
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try
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{
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using (PyObject gcModule = PythonEngine.ImportModule("gc"))
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using (PyObject pyCollect = gcModule.GetAttr("collect"))
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{
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long span1 = CompareWithFinalizerOn(pyCollect, false);
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long span2 = CompareWithFinalizerOn(pyCollect, true);
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Assert.Less(span2, span1);
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}
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}
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finally
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{
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Finalizer.Instance.Enable = oldState;
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}
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}
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class MyPyObject : PyObject
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{
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public MyPyObject(IntPtr op) : base(op)
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{
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}
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protected override void Dispose(bool disposing)
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{
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base.Dispose(disposing);
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GC.SuppressFinalize(this);
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throw new Exception("MyPyObject");
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}
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internal static void CreateMyPyObject(IntPtr op)
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{
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Runtime.Runtime.XIncref(op);
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new MyPyObject(op);
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}
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}
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[Test]
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public void ErrorHandling()
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{
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bool called = false;
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EventHandler<Finalizer.ErrorArgs> handleFunc = (sender, args) =>
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{
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called = true;
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Assert.AreEqual(args.Error.Message, "MyPyObject");
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};
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Finalizer.Instance.Threshold = 1;
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Finalizer.Instance.ErrorHandler += handleFunc;
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try
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{
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WeakReference shortWeak;
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WeakReference longWeak;
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{
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MakeAGarbage(out shortWeak, out longWeak);
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var obj = (PyLong)longWeak.Target;
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IntPtr handle = obj.Handle;
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shortWeak = null;
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longWeak = null;
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MyPyObject.CreateMyPyObject(handle);
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obj.Dispose();
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obj = null;
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}
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FullGCCollect();
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Finalizer.Instance.Collect();
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Assert.IsTrue(called);
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}
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finally
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{
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Finalizer.Instance.ErrorHandler -= handleFunc;
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}
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}
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[Test]
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public void ValidateRefCount()
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{
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if (!Finalizer.Instance.RefCountValidationEnabled)
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{
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Assert.Pass("Only run with FINALIZER_CHECK");
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}
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IntPtr ptr = IntPtr.Zero;
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bool called = false;
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Finalizer.IncorrectRefCntHandler handler = (s, e) =>
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{
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called = true;
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Assert.AreEqual(ptr, e.Handle);
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Assert.AreEqual(2, e.ImpactedObjects.Count);
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// Fix for this test, don't do this on general environment
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Runtime.Runtime.XIncref(e.Handle);
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return false;
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};
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Finalizer.Instance.IncorrectRefCntResolver += handler;
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try
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{
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ptr = CreateStringGarbage();
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FullGCCollect();
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Assert.Throws<Finalizer.IncorrectRefCountException>(() => Finalizer.Instance.Collect());
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Assert.IsTrue(called);
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}
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finally
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{
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Finalizer.Instance.IncorrectRefCntResolver -= handler;
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}
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}
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private static IntPtr CreateStringGarbage()
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{
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PyString s1 = new PyString("test_string");
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// s2 steal a reference from s1
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PyString s2 = new PyString(s1.Handle);
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return s1.Handle;
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}
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}
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}

‎src/embed_tests/TestPyAnsiString.cs

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const string expected = "foo";
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var t = new PyAnsiString(expected);
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Runtime.Runtime.XIncref(t.Handle);
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var actual = new PyAnsiString(t.Handle);
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Assert.AreEqual(expected, actual.ToString());

‎src/embed_tests/TestPyFloat.cs

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public void IntPtrCtor()
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{
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var i = new PyFloat(1);
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Runtime.Runtime.XIncref(i.Handle);
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var ii = new PyFloat(i.Handle);
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Assert.AreEqual(i.Handle, ii.Handle);
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}

‎src/embed_tests/TestPyInt.cs

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@@ -86,6 +86,7 @@ public void TestCtorSByte()
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public void TestCtorPtr()
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{
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var i = new PyInt(5);
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Runtime.Runtime.XIncref(i.Handle);
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var a = new PyInt(i.Handle);
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Assert.AreEqual(5, a.ToInt32());
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}
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public void TestCtorPyObject()
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{
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var i = new PyInt(5);
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Runtime.Runtime.XIncref(i.Handle);
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var a = new PyInt(i);
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Assert.AreEqual(5, a.ToInt32());
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}

‎src/embed_tests/TestPyLong.cs

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@@ -102,6 +102,7 @@ public void TestCtorDouble()
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public void TestCtorPtr()
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{
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var i = new PyLong(5);
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Runtime.Runtime.XIncref(i.Handle);
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var a = new PyLong(i.Handle);
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Assert.AreEqual(5, a.ToInt32());
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}
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public void TestCtorPyObject()
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{
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var i = new PyLong(5);
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Runtime.Runtime.XIncref(i.Handle);
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var a = new PyLong(i);
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Assert.AreEqual(5, a.ToInt32());
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}

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