ensure Py handles are inaccessible after PythonException is disposed (#1055)

lostmsu · web-flow · commit a424998ec6d5 · 2020-02-23T18:01:19.000+01:00
diff --git a/src/runtime/pythonexception.cs b/src/runtime/pythonexception.cs
@@ -21,7 +21,7 @@ public class PythonException : System.Exception, IPyDisposable
         public PythonException()
         {
             IntPtr gs = PythonEngine.AcquireLock();
-            Runtime.PyErr_Fetch(ref _pyType, ref _pyValue, ref _pyTB);
+            Runtime.PyErr_Fetch(out _pyType, out _pyValue, out _pyTB);
             if (_pyType != IntPtr.Zero && _pyValue != IntPtr.Zero)
             {
                 string type;
@@ -161,12 +161,23 @@ public void Dispose()
                 if (Runtime.Py_IsInitialized() > 0 && !Runtime.IsFinalizing)
                 {
                     IntPtr gs = PythonEngine.AcquireLock();
-                    Runtime.XDecref(_pyType);
-                    Runtime.XDecref(_pyValue);
+                    if (_pyType != IntPtr.Zero)
+                    {
+                        Runtime.XDecref(_pyType);
+                        _pyType= IntPtr.Zero;
+                    }
+
+                    if (_pyValue != IntPtr.Zero)
+                    {
+                        Runtime.XDecref(_pyValue);
+                        _pyValue = IntPtr.Zero;
+                    }
+
                     // XXX Do we ever get TraceBack? //
                     if (_pyTB != IntPtr.Zero)
                     {
                         Runtime.XDecref(_pyTB);
+                        _pyTB = IntPtr.Zero;
                     }
                     PythonEngine.ReleaseLock(gs);
                 }
diff --git a/src/runtime/runtime.cs b/src/runtime/runtime.cs
@@ -1933,7 +1933,7 @@ internal static IntPtr PyMem_Realloc(IntPtr ptr, long size)
         internal static extern IntPtr PyErr_Occurred();
 
         [DllImport(_PythonDll, CallingConvention = CallingConvention.Cdecl)]
-        internal static extern void PyErr_Fetch(ref IntPtr ob, ref IntPtr val, ref IntPtr tb);
+        internal static extern void PyErr_Fetch(out IntPtr ob, out IntPtr val, out IntPtr tb);
 
         [DllImport(_PythonDll, CallingConvention = CallingConvention.Cdecl)]
         internal static extern void PyErr_Restore(IntPtr ob, IntPtr val, IntPtr tb);

Original file line number	Diff line number	Diff line change
`@@ -21,7 +21,7 @@ public class PythonException : System.Exception, IPyDisposable`
`21`	`21`	`public PythonException()`
`22`	`22`	`{`
`23`	`23`	`IntPtr gs = PythonEngine.AcquireLock();`
`24`		`- Runtime.PyErr_Fetch(ref _pyType, ref _pyValue, ref _pyTB);`
	`24`	`+ Runtime.PyErr_Fetch(out _pyType, out _pyValue, out _pyTB);`
`25`	`25`	`if (_pyType != IntPtr.Zero && _pyValue != IntPtr.Zero)`
`26`	`26`	`{`
`27`	`27`	`string type;`
`@@ -161,12 +161,23 @@ public void Dispose()`
`161`	`161`	`if (Runtime.Py_IsInitialized() > 0 && !Runtime.IsFinalizing)`
`162`	`162`	`{`
`163`	`163`	`IntPtr gs = PythonEngine.AcquireLock();`
`164`		`- Runtime.XDecref(_pyType);`
`165`		`- Runtime.XDecref(_pyValue);`
	`164`	`+ if (_pyType != IntPtr.Zero)`
	`165`	`+ {`
	`166`	`+ Runtime.XDecref(_pyType);`
	`167`	`+ _pyType= IntPtr.Zero;`
	`168`	`+ }`
	`169`	`+`
	`170`	`+ if (_pyValue != IntPtr.Zero)`
	`171`	`+ {`
	`172`	`+ Runtime.XDecref(_pyValue);`
	`173`	`+ _pyValue = IntPtr.Zero;`
	`174`	`+ }`
	`175`	`+`
`166`	`176`	`// XXX Do we ever get TraceBack? //`
`167`	`177`	`if (_pyTB != IntPtr.Zero)`
`168`	`178`	`{`
`169`	`179`	`Runtime.XDecref(_pyTB);`
	`180`	`+ _pyTB = IntPtr.Zero;`
`170`	`181`	`}`
`171`	`182`	`PythonEngine.ReleaseLock(gs);`
`172`	`183`	`}`