Caching improvements

[dirk]

Implementation of the serialization-deserialization-overhead-eliminating strategy outlined in #289. Please see that issue for an outline and general details of the strategy.

[rails-bot]

Thanks for the pull request, and welcome! The Rails team is excited to review your changes, and you should hear from @rwz (or someone else) soon.

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[dirk]

Please see this comment on the proposal pull request for performance results.

[peteygao]

Is this an oversight? We shouldn't need to bring in the entire Rails gem into jbuilder, right?

[rromanchuk]

@dirk would love to try this out, do you have a fork you are maintaining for your own projects?

[rromanchuk]

have you seen before?

ActionView::Template::Error (can't add a new key into hash during iteration): occurs when there is another nested cache!

[mactkg]

@rromanchuk I think the error is raised when a template call same template itself.

# model/_template.jbuilder
if model[:child].present?
  json.child model[:child], partial: 'model/template', as: :model
else
  json.child []
end