Use a local Status variable

Using a local reference ensure that the Status object cannot be disposed before the Dispose. This way it's also possible to use an external Status instance instead of the static one, if needed.

Author: Superpiffer

src/TensorFlowNET.Core/Sessions/BaseSession.cs

@@ -30,6 +30,7 @@ namespace Tensorflow
     public class BaseSession : DisposableObject
     {
         protected Graph _graph;
+        protected Status _status;
         public Graph graph => _graph;
 
         public BaseSession(IntPtr handle, Graph g)
@@ -48,9 +49,9 @@ public BaseSession(string target = "", Graph g = null, ConfigProto config = null
             }
 
             using var opts = new SessionOptions(target, config);
-            status = status ?? tf.Status;
-            _handle = c_api.TF_NewSession(_graph, opts.Handle, status.Handle);
-            status.Check(true);
+            _status = status ?? tf.Status;
+            _handle = c_api.TF_NewSession(_graph, opts.Handle, _status.Handle);
+            _status.Check(true);
         }
 
         public virtual void run(Operation op, params FeedItem[] feed_dict)
@@ -217,8 +218,6 @@ private unsafe NDArray[] _call_tf_sessionrun(KeyValuePair<TF_Output, Tensor>[] f
             // Ensure any changes to the graph are reflected in the runtime.
             _extend_graph();
 
-            var status = tf.Status;
-
             var output_values = fetch_list.Select(x => IntPtr.Zero).ToArray();
 
             c_api.TF_SessionRun(_handle,
@@ -232,9 +231,9 @@ private unsafe NDArray[] _call_tf_sessionrun(KeyValuePair<TF_Output, Tensor>[] f
                 target_opers: target_list.Select(f => (IntPtr)f).ToArray(),
                 ntargets: target_list.Count,
                 run_metadata: IntPtr.Zero,
-                status: status.Handle);
+                status: _status.Handle);
 
-            status.Check(true);
+            _status.Check(true);
 
             var result = new NDArray[fetch_list.Length];
 
@@ -246,8 +245,6 @@ private unsafe NDArray[] _call_tf_sessionrun(KeyValuePair<TF_Output, Tensor>[] f
 
         public unsafe Tensor eval(Tensor tensor)
         {
-            var status = tf.Status;
-
             var output_values = new IntPtr[1];
             var fetch_list = new[] { tensor._as_tf_output() };
 
@@ -262,9 +259,9 @@ public unsafe Tensor eval(Tensor tensor)
                 target_opers: new IntPtr[0],
                 ntargets: 0,
                 run_metadata: IntPtr.Zero,
-                status: status.Handle);
+                status: _status.Handle);
 
-            status.Check(true);
+            _status.Check(true);
 
             return new Tensor(new SafeTensorHandle(output_values[0]));
         }
@@ -291,15 +288,7 @@ private void _extend_graph()
         protected override void DisposeUnmanagedResources(IntPtr handle)
         {
             // c_api.TF_CloseSession(handle, tf.Status.Handle);
-            if (tf.Status == null || tf.Status.Handle.IsInvalid)
-            {
-                using var status = new Status();
-                c_api.TF_DeleteSession(handle, status.Handle);
-            }
-            else
-            {
-                c_api.TF_DeleteSession(handle, tf.Status.Handle);
-            }
+            c_api.TF_DeleteSession(handle, _status.Handle);
         }
     }
 }