commit 0a3864f81e3f660151ce452b228dbce0338c553e
author Shihao Xu <shihaoxu@fb.com> Wed Mar 25 18:36:48 2020 -0700
committer Facebook GitHub Bot <facebook-github-bot@users.noreply.github.com> Wed Mar 25 18:40:05 2020 -0700
tree 12995fde853f94fc2ab23d9419ed773d94b2aea7
parent efbd6b8533bfa42f9e57d11b453b8a8bf4cf18ea

Throw an actionable error message on user call rref<ScriptModule>.to_here() in torchscript (#35369)

Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/35369

For issue, https://github.com/pytorch/pytorch/issues/35367

Test Plan:
```
buck build mode/dev-nosan //caffe2/test/distributed/rpc/jit:rpc_fork \
&& buck-out/gen/caffe2/test/distributed/rpc/jit/rpc_fork\#binary.par \
-r test_remote_script_module

buck build mode/dev-nosan //caffe2/test/distributed/rpc/jit:rpc_fork \
&& buck-out/gen/caffe2/test/distributed/rpc/jit/rpc_fork\#binary.par \
-r test_torchscript_functions_not_supported
```

Differential Revision: D7870906

fbshipit-source-id: 2e78f2e620a5cc7c8f26ab35400ba33bb303788d

torch/csrc/distributed/rpc/rref_impl.cpp

diff --git a/torch/csrc/distributed/rpc/rref_impl.cpp b/torch/csrc/distributed/rpc/rref_impl.cpp
index f6fe2bd..42341be 100644
--- a/torch/csrc/distributed/rpc/rref_impl.cpp
+++ b/torch/csrc/distributed/rpc/rref_impl.cpp
@@ -115,6 +115,19 @@
       " and ForkId=",
       forkId(),
       " has been deleted. Cannot call to_here() on it after deletion.");
+  TORCH_CHECK(
+      !type_->is_module(),
+      "User RRef with RRefId=",
+      rrefId(),
+      " and ForkId=",
+      forkId(),
+      " is an RRef to a ScriptModule. "
+      "It can't be sent through RPC "
+      "from owner, ",
+      ownerName(),
+      ", to user, ",
+      RpcAgent::getCurrentRpcAgent()->getWorkerInfo().name_,
+      ".");
 
   auto agent = RpcAgent::getCurrentRpcAgent();
 

torch/testing/_internal/distributed/rpc/jit/rpc_test.py

diff --git a/torch/testing/_internal/distributed/rpc/jit/rpc_test.py b/torch/testing/_internal/distributed/rpc/jit/rpc_test.py
index e5c75a7..7e95168 100644
--- a/torch/testing/_internal/distributed/rpc/jit/rpc_test.py
+++ b/torch/testing/_internal/distributed/rpc/jit/rpc_test.py
@@ -691,6 +691,16 @@
         )
         self.assertEqual(ret, local_ret)
 
+        # pass rref arg to self/user
+        with self.assertRaisesRegex(
+            RuntimeError, "is an RRef to a ScriptModule. It can't be sent through RPC from owner,"
+        ):
+            ret = rpc.rpc_sync(
+                worker_name(self.rank),
+                run_ref_script_module,
+                args=(remote_ref, torch.ones(self.rank)),
+            )
+
     @dist_init
     def test_rref_is_owner(self):
         n = self.rank + 1