@Frederik-Baetens SOrry for the long delay in responding here. By default the gem will attempt to use cache_key_with_version or cache_key on the object. In a Rails environment this corresponds to the ActiveRecord implementations of these methods. As to why inspect has an effect on the caching behavior...I have no idea. I will look into why that may be the case. My gut says that fetch is likely not returning the flat value but some kind of wrapper 🤷‍♂️

Can you update here with the versions you are using for Rails, graphql-ruby, and graphql-cache?

graphql-cache (0.6.0)
rails (5.1.7)
graphql (1.9.4)
ruby 2.6.3p62

Sorry for the late response, we aren't really looking into caching anymore, because we realized that our heaviest queries can't be cached anyways. But i do wish you good luck in solving this issue.

Maybe the other people that have liked my issue can provide you with some more context on exactly what they were doing when they had this issue.

i did see something in the rails 6.0.1 release that seems very relevant to this:

Fixed that mutating a value returned by a memory cache store would unexpectedly change the cached value.