pytorch

010b9c52 - Skip None submodule during JIT-tracing (#49765)

Skip None submodule during JIT-tracing (#49765) Summary: Pull Request resolved: https://github.com/pytorch/pytorch/pull/49765 Some PyTorch module can have None as submodule, which causes the following error in JIT-tracing: Repro script: ``` import torch class TestModule(torch.nn.Module): def __init__(self): super().__init__() self.submod = torch.nn.Linear(3, 4) self.submod = None def forward(self, inputs): return inputs m = TestModule() tm = torch.jit.trace(m, torch.tensor(1.)) ``` Error: ``` Traceback (most recent call last): File "<stdin>", line 1, in <module> File "/data/miniconda3/envs/master_nightly/lib/python3.7/site-packages/torch/jit/_trace.py", line 742, in trace _module_class, File "/data/miniconda3/envs/master_nightly/lib/python3.7/site-packages/torch/jit/_trace.py", line 928, in trace_module module = make_module(mod, _module_class, _compilation_unit) File "/data/miniconda3/envs/master_nightly/lib/python3.7/site-packages/torch/jit/_trace.py", line 560, in make_module return _module_class(mod, _compilation_unit=_compilation_unit) File "/data/miniconda3/envs/master_nightly/lib/python3.7/site-packages/torch/jit/_trace.py", line 1039, in __init__ submodule, TracedModule, _compilation_unit=None File "/data/miniconda3/envs/master_nightly/lib/python3.7/site-packages/torch/jit/_trace.py", line 560, in make_module return _module_class(mod, _compilation_unit=_compilation_unit) File "/data/miniconda3/envs/master_nightly/lib/python3.7/site-packages/torch/jit/_trace.py", line 988, in __init__ assert isinstance(orig, torch.nn.Module) AssertionError ``` This pull request changes the JIT-tracing logic to skip the None submodule when tracing. Test Plan: `buck test mode/dev //caffe2/test:jit -- test_trace_skip_none_submodule` Reviewed By: wanchaol Differential Revision: D25670948 fbshipit-source-id: 468f42f5ddbb8fd3de06d0bc224dc67bd7172358