GILState.Dispose is safe to be called multiple times (pythonnet#1037)

lostmsu · AlexCatarino · commit a35d5469fd6f · 2020-06-27T02:56:37.000+01:00
* GILState.Dispose is safe to be called multiple times
* test multiple class to GILState.Dispose
diff --git a/src/embed_tests/TestGILState.cs b/src/embed_tests/TestGILState.cs
@@ -0,0 +1,21 @@
+namespace Python.EmbeddingTest
+{
+    using NUnit.Framework;
+    using Python.Runtime;
+
+    public class TestGILState
+    {
+        /// <summary>
+        /// Ensure, that calling <see cref="Py.GILState.Dispose"/> multiple times is safe
+        /// </summary>
+        [Test]
+        public void CanDisposeMultipleTimes()
+        {
+            using (var gilState = Py.GIL())
+            {
+                for(int i = 0; i < 50; i++)
+                    gilState.Dispose();
+            }
+        }
+    }
+}
diff --git a/src/runtime/pythonengine.cs b/src/runtime/pythonengine.cs
@@ -645,7 +645,8 @@ public static PyScope CreateScope(string name)
         
         public class GILState : IDisposable
         {
-            private IntPtr state;
+            private readonly IntPtr state;
+            private bool isDisposed;
 
             internal GILState()
             {
@@ -654,8 +655,11 @@ internal GILState()
 
             public void Dispose()
             {
+                if (this.isDisposed) return;
+
                 PythonEngine.ReleaseLock(state);
                 GC.SuppressFinalize(this);
+                this.isDisposed = true;
             }
 
             ~GILState()

Original file line number	Diff line number	Diff line change
`@@ -645,7 +645,8 @@ public static PyScope CreateScope(string name)`
`645`	`645`
`646`	`646`	`public class GILState : IDisposable`
`647`	`647`	`{`
`648`		`- private IntPtr state;`
	`648`	`+ private readonly IntPtr state;`
	`649`	`+ private bool isDisposed;`
`649`	`650`
`650`	`651`	`internal GILState()`
`651`	`652`	`{`
`@@ -654,8 +655,11 @@ internal GILState()`
`654`	`655`
`655`	`656`	`public void Dispose()`
`656`	`657`	`{`
	`658`	`+ if (this.isDisposed) return;`
	`659`	`+`
`657`	`660`	`PythonEngine.ReleaseLock(state);`
`658`	`661`	`GC.SuppressFinalize(this);`
	`662`	`+ this.isDisposed = true;`
`659`	`663`	`}`
`660`	`664`
`661`	`665`	`~GILState()`