stackshareio/graphql-cache

"singleton can't be dumped" exception when trying to cache a BatchLoader field

bill-kolokithas opened this issue · 4 comments

bill-kolokithas commented

Hello. When using BatchLoader gem to... batch load a field, the following error is returned when trying to cache it:


  singleton can't be dumped
    /home/billk/.gem/ruby/2.3.0/gems/activesupport-5.1.6/lib/active_support/cache.rb:665:in `dump'
    /home/billk/.gem/ruby/2.3.0/gems/activesupport-5.1.6/lib/active_support/cache.rb:665:in `dup_value!'
    /home/billk/.gem/ruby/2.3.0/gems/activesupport-5.1.6/lib/active_support/cache/memory_store.rb:130:in `write_entry'
    /home/billk/.gem/ruby/2.3.0/gems/activesupport-5.1.6/lib/active_support/cache.rb:400:in `block in write'
    ...

I haven't tested with https://github.com/Shopify/graphql-batch. Maybe there is a problem with lazy fields in general?

uzzer commented

I have the same issue when using Rails.cache without this gem, so the problem is somewhere outside of graphql-cache.

uzzer commented

In my case, the reason was the fact that only serializable objects could be cached. e.g. I did try to cache FactoryBot build_stubbed thing. @freestyl3r please check is it your case

bill-kolokithas commented

Yeah, it's a limitation of Marshal used internally by rails cache.

Some objects cannot be dumped: if the objects to be dumped include bindings, procedure or method objects, instances of class IO, or singleton objects, a TypeError will be raised.

If we provide marshal_dump & marshal_load methods, maybe we can make this work.

thebadmonkeydev commented

Since this is a problem with Rails.cache and not graphql-cache, I'm going to close this issue.