Is `circular` option expected to work with `rails` mode and ActiveSupport loaded ?

[lioneldebauge]

Hello 👋

While using Oj I found out it was not able to handle circular references when ActiveSupport was loaded in rails mode. I was wondering if this was expected. I could not find a mention of this special case in the documentation at least.

require("bundler/inline")

gemfile do
  source("https://rubygems.org")
  gem("oj", "3.16.11")
  gem("activesupport", "8.0.3")
end

require("oj")
require("active_support/all")

begin
  a = []
  b = []
  a.push(b)
  b.push(a)
  Oj.dump(a, mode: :rails, circular: true)
  puts("SUCCESS: handled circular reference with circular: true")
rescue SystemStackError
  puts("ERROR: SystemStackError triggered because of circular reference")
end

Thanks a lot for any help you can give me 🙏

[ohler55]

The docs might be confusing as the modes table seems to indicated the :circular option is supported in all modes when the support is different for each mode as described in https://github.com/ohler55/oj/blob/develop/pages/Options.md#circular-boolean.

[lioneldebauge]

Shouldn't :circular option allow to avoid triggering SystemStackError despite the various support for rails mode though ? It seems to not work if ActiveSupport is loaded.

While loading ActiveSupport

require("bundler/inline")

gemfile do
  source("https://rubygems.org")
  gem("oj", "3.16.11")
  gem("activesupport", "8.0.3")
end

require("oj")
require("active_support/all")

begin
  a = []
  b = []
  a.push(b)
  b.push(a)
  Oj.dump(a, mode: :rails, circular: true)
  puts("SUCCESS: handled circular reference with circular: true") # this will be returned
rescue SystemStackError
  puts("ERROR: SystemStackError triggered because of circular reference")
end

Without loading ActiveSupport

require("bundler/inline")

gemfile do
  source("https://rubygems.org")
  gem("oj", "3.16.11")
  gem("activesupport", "8.0.3")
end

require("oj")
# require("active_support/all")

begin
  a = []
  b = []
  a.push(b)
  b.push(a)
  Oj.dump(a, mode: :rails, circular: true)
  puts("SUCCESS: handled circular reference with circular: true")
rescue SystemStackError
  puts("ERROR: SystemStackError triggered because of circular reference") # this will be returned
end

[ohler55]

ActiveSupport monkey patches all objects to add or over-write any existing JSON encoding methods. What yiou are most likely seeing if you look at the stack are calls to the ActiveSupport methods.