v3.16.17 unexpected changes

[Epigene]

Hi, I just upgraded Oj from v3.16.16 to v3.16.17 and some of json-response actions in our Rails app no longer return expected data.
We're setting Oj.optimize_rails.

For example

render json: collection.to_json(only: [:id, :code], methods: %i[company_and_code])

The methods part is no longer included, and company_and_code key is absent.

Any suggestions about how to fix this?

I should mention changing the action code to render json: collection.as_json(only: [:id, :code], methods: %i[company_and_code]) returns the expected data, but I can't be expected to dig through the many actions we have.

[ohler55]

What does the native json do? Does it act the way you expect?

[rlineweaver]

We also experienced this regression in v3.16.17 -- it appears the opts are not getting passed along to subsequent collection items. I was able to demonstrate this issue by overriding as_json in a simple ActiveRecord model like this:

class Role < ApplicationRecord

    def as_json(opts = {})
        return { got_opts: true } if opts[:got_opts]

        super
    end

end

Then, in a Rails console:

> JSON.parse Role.last(3).to_json(got_opts: true)
=> 
[{"got_opts" => true},
 {"id" => "aecec9c6-f983-4891-87aa-560eba6f08b2",
  "name" => "editor",
  "resource_id" => "90c750c7-97fd-4bb6-9d91-f1273a76daa2",
  "resource_type" => "Lesson",
  "created_at" => "2026-03-12T18:08:08.272Z",
  "updated_at" => "2026-03-12T18:08:08.272Z"},
 {"id" => "aa9a4562-17cc-4921-a8f0-e67dd65a5521",
  "name" => "editor",
  "resource_id" => "0f740ee0-8f58-4f7d-8b76-2e7dbbb17a48",
  "resource_type" => "Lesson",
  "created_at" => "2026-03-12T18:17:21.409Z",
  "updated_at" => "2026-03-12T18:17:21.409Z"}]

(as_json received the opts for the first item, but not for the subsequent instances)

If I comment out Oj.optimize_rails, it works as expected:

> JSON.parse Role.last(3).to_json(got_opts: true)
=> [{"got_opts" => true}, {"got_opts" => true}, {"got_opts" => true}] 

This works fine on v3.16.16.

[ohler55]

That is very helpful. It gives me a place to start. Thanks.

[rgaufman]

I've just hit the same bug and had to revert back to an older version:

 # Direct via the encoder Oj installed:
  ActiveSupport::JSON.encode(camera, only: %i[_id], methods: %i[detect_port])
  # => {"_id":"..."}  # <= methods gets stripped

[ohler55]

The change was an attempt to optimize Hash objects and trying to find the balance between optimizing and letting the rails monkey patch have control. I'll try to find a better compromise. Maybe insist on a direct optimize of Hash and not include it in the general optimize. Any thoughts on that?

[ohler55]

Would it be acceptable to call Oj::Rails.deoptimize(Hash) if the optimized behavior is no desired?

[Viktor-Ivliev]

@ohler55 Oj::Rails.deoptimize(Hash) That didn't help either; the problem is solely in methods. Thankfully, there weren't many such instances in our project, so I replaced them by manually creating a hash.