Modify Marshal to dump objects larger than 2 GiB
Using a gem called Numo-array to handle matrix operations, I found the following error while saving a large matrix:
in `dump': long too big to dump (TypeError)
Github thread is https://github.com/ruby-numo/numo-narray/issues/144. Digging with the authors, I found the following code that reproduces the error:
ruby -e 'Marshal.dump(" "*2**31)'
ruby 2.7.0dev (2019-11-12T12:03:22Z master 3816622fbe) [x86_64-linux]
The marshal library has a limit based on constant
SIZEOF_LONG. This check is performed in here. I don't understand the motivation of this limit. It has a great impact on libraries that need to serialize large objects such as numeric matrix. In this case, the limit >= 2 GiB is reached easily, and it blocks ruby development. I found another related bug report: #1560, but the Marshal problem was not addressed in it.