Throw an exception in the constructor of torchscript serialization to avoid double-exception (#44266)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/44266
If PyTorchStreamWriter is writing to a file in a non-existing path, it throws an exception. In unwinding the destructor calls writeEndOfFile() and throws again. To avoid this double-exception, a check and throw is added in the constructor. In such case the destructor will not be called and the exception can go through the unwinding.
Test Plan: python test/test_jit.py TestSaveLoad.test_save_nonexit_file
Reviewed By: dreiss
Differential Revision: D23560770
Pulled By: iseeyuan
fbshipit-source-id: 51b24403500bdab3578c7fd5e017780467a5d06a
