fix interpreter determin output leaf and grad (#4872)

* fix interpreter determin output leaf and grad

* fix GradMode get

* simplify

* add test for no_grad

Co-authored-by: oneflow-ci-bot <69100618+oneflow-ci-bot@users.noreply.github.com>

oneflow/core/framework/op_interpreter/op_interpreter.cpp

@@ -146,18 +146,18 @@ Maybe<void> DetermineRequiresGrad(TensorTuple* outputs, const bool& requires_gra
 Maybe<void> AutogradInterpreter::Apply(const OpExpr& op_expr, const TensorTuple& inputs,
                                        TensorTuple* outputs, const AttrMap& attrs) const {
   bool requires_grad = false;
+  if (autograd::GradMode::is_enabled() && !JUST(op_expr.IsGradDisabled())) {
+    requires_grad =
+        std::any_of(inputs.begin(), inputs.end(),
+                    [](const std::shared_ptr<Tensor>& tensor) { return tensor->requires_grad(); });
+  }
   {
     autograd::AutoGradMode mode(false);
     JUST(internal_->Apply(op_expr, inputs, outputs, attrs));
-    if (!JUST(op_expr.IsGradDisabled())) {
-      requires_grad = std::any_of(
-          inputs.begin(), inputs.end(),
-          [](const std::shared_ptr<Tensor>& tensor) { return tensor->requires_grad(); });
-    }
     JUST(DetermineIsLeaf(outputs, inputs.size() == 0, requires_grad));
     JUST(DetermineRequiresGrad(outputs, requires_grad));
   }
-  if (autograd::GradMode::is_enabled() && requires_grad) {
+  if (requires_grad) {
     const auto& grad_closure = JUST(op_expr.GetOrCreateOpGradClosure());
     grad_closure->Capture(inputs, *outputs, attrs);
 

oneflow/python/test/tensor/test_tensor.py

@@ -160,6 +160,11 @@ class TestTensor(flow.unittest.TestCase):
         test_case.assertTrue(z.requires_grad)
         test_case.assertFalse(z.is_leaf)
 
+        with flow.no_grad():
+            m = x + y
+        test_case.assertTrue(m.is_leaf)
+        test_case.assertFalse(m.requires_grad)
+
         v = flow.Tensor(*shape, requires_grad=True)
         z.retain_grad()
         w = v + z