ruby - Breaking changes in Rails 4 JSON rendering? -

i started new app atop rails 4 , i've noticed seems breaking change in how json rendering implemented default, can't find written anywhere wondering if can give me insight on (1) whether api has changed , (2) how can obtain behavior need (namely, old behavior).

in particular, i'm seeing that, in rails 3

@answer.as_json 

...would return...

{   id: 1,   body: "lorem ipsum..."   .... } 

in rails 4 seems same method returning:

{   'answer':     {       id: 1,       body: "lorem ipsum..."       ...     } } 

can else confirm behavior has changed? there way old behavior short of overriding as_json every model?

this new implementation making more cumbersome return json responses containing multiple models (which either have done hash merge in "render :json ..." call in controller action or overriding as_json).

there option activerecord::base.include_root_in_json controls top-level behaviour of as_json method. name self-explanatory, guess.

as breaking api change: if dig source, can see default value option changed true in rails 4.0.0.beta1 later reverted false in rails 4.0.0.rc1.

if want sure json not contain root node, specify include_root_in_json option in config/initializers/wrap_parameters.rb:

activesupport.on_load(:active_record)   self.include_root_in_json = false end