Use sub scope in tensor_array_to_tensor op. (#14524)

test=develop

paddle/fluid/framework/executor.cc

@@ -392,8 +392,8 @@ void Executor::RunPreparedContext(ExecutorPrepareContext* ctx, Scope* scope,
 
   int64_t max_memory_size = GetEagerDeletionThreshold();
   std::unique_ptr<GarbageCollector<Tensor>> gc;
-  // WhileOp would set keep_kids to false
-  // WhileGradOp would need the scopes created in WhileOp
+  // WhileOp would set keep_kids to true,
+  // because WhileGradOp needs the scopes created in WhileOp.
   // Perhaps, we should not perform eager deletion in WhileOp
   // The scopes and variables created by WhileOp would be deleted
   // in WhileGradOp.

paddle/fluid/inference/api/analysis_predictor.cc

@@ -174,7 +174,6 @@ bool AnalysisPredictor::Run(const std::vector<PaddleTensor> &inputs,
   inference::Timer timer;
   timer.tic();
   // set feed variable
-  std::vector<framework::LoDTensor> feeds;
   framework::Scope *scope = sub_scope_ ? sub_scope_ : scope_.get();
   if (!SetFeed(inputs, scope)) {
     LOG(ERROR) << "fail to set feed";

paddle/fluid/inference/api/api_impl.cc

@@ -138,7 +138,6 @@ bool NativePaddlePredictor::Run(const std::vector<PaddleTensor> &inputs,
   Timer timer;
   timer.tic();
   // set feed variable
-  std::vector<framework::LoDTensor> feeds;
   framework::Scope *scope = sub_scope_ != nullptr ? sub_scope_ : scope_.get();
   if (!SetFeed(inputs, scope)) {
     LOG(ERROR) << "fail to set feed";

paddle/fluid/operators/tensor_array_to_tensor_op.cc

@@ -106,9 +106,9 @@ class LoDTensorArray2TensorOp : public framework::OperatorBase {
     out_inx_dim[0] = inx.size();
     out_inx.Resize(out_inx_dim);
 
+    auto &local_scope = scope.NewScope();
     std::string var_name = "out_index";
-    framework::Variable *tmp_index_var =
-        const_cast<framework::Scope &>(scope).Var(var_name);
+    framework::Variable *tmp_index_var = local_scope.Var(var_name);
     auto &tmp_index_tensor =
         *(tmp_index_var->GetMutable<paddle::framework::LoDTensor>());
     tmp_index_tensor.Resize(out_inx_dim);
@@ -128,12 +128,12 @@ class LoDTensorArray2TensorOp : public framework::OperatorBase {
     out_dims[axis] = out_dim_sum;
     out.Resize(out_dims);
 
-    LodTensorArray2LodTensorVector(scope, base_name, Input("X"), &names);
-    // Invoke Reshape Op
+    LodTensorArray2LodTensorVector(local_scope, base_name, Input("X"), &names);
+    // Invoke concat Op
     auto concat_op = framework::OpRegistry::CreateOp(
         "concat", {{"X", names}}, {{"Out", {Output("Out")}}}, attrs);
 
-    concat_op->Run(scope, place);
+    concat_op->Run(local_scope, place);
   }
 };