Unexpected 'NoMethodError' when accessing nested attributes in Rails 7.1 with polymorphic associations
I'm writing unit tests and I've hit a wall trying to I've looked through the documentation and I'm still confused about I'm working with a `NoMethodError` when trying to access nested attributes of a polymorphic association in my Rails 7.1 application... I have two models, `Comment` and `Post`, where `Comment` belongs to a `commentable` polymorphic interface (it can belong to either a `Post` or another model). The scenario arises when I attempt to create or update a `Comment` with nested attributes for `Post` in my controller. Here’s the relevant part of my `Comment` model: ```ruby class Comment < ApplicationRecord belongs_to :commentable, polymorphic: true accepts_nested_attributes_for :commentable end ``` And my `Post` model looks like this: ```ruby class Post < ApplicationRecord has_many :comments, as: :commentable end ``` In my controller, I have the following action to create a new comment: ```ruby class CommentsController < ApplicationController def create @comment = Comment.new(comment_params) if @comment.save redirect_to @comment.commentable else render 'new' end end private def comment_params params.require(:comment).permit(:content, commentable_attributes: [:id, :title]) end end ``` When I send a POST request to create a comment with nested `Post` attributes like this: ```json { "comment": { "content": "This is a comment.", "commentable_attributes": { "id": 1, "title": "New Title" } } } ``` I get the following behavior: ``` NoMethodError - undefined method `commentable_attributes' for #<Comment:0x00007fe8e3b9a5b8> ``` I've already verified that my routes are correctly set up, and I've tried changing `accepts_nested_attributes_for :commentable` to include `:post` specifically, but that doesn't seem to help. I also checked that the `Post` model has the proper attributes defined. Is there something I'm missing about how to structure this polymorphic relationship or how to use nested attributes correctly in this context?