Mini_Spinach issues

Results 3 issues of


                                            Mini_Spinach

Why only SCOPE_SUCCESS macro accepts the default non-noexcept lambda？

In [ScopeGuard.h](https://github.com/facebook/folly/blob/fe501cc8a66f432c405d16fc348e83cb56c563da/folly/ScopeGuard.h#L304)，i can figure out that： 1. **ExecuteOnException in ScopeGuardForNewException** corresponds to **InvokeNoexcept in ScopeGuardImpl**. 2. **InvokeNoexcept(true) via SCOPE_EXIT and SCOPE_FAIL** makes dtor() and execute() noexcept in ScopeGuardImpl，so after function_...

Why ref_counter of HdfsFileSystem isn't designed with atomic_int_type ？

If last HDFSStream or singleton HdfsFilesystem object is descructed, i'm confused about "ref_counter_[0] -= 1" might not achieve the desired effect, which will lead to hdfsFS not disconnected. Could you...

A question about minibatch.py::_remove_isolated

When generating train_edges in _remove_isolated() function, the legal edges seem like: node(train) node(train) node(train) node(test) node(valid) node(test) node(test) node(test) node(train) represents the node with train symbol. Why those 4 types...