NoMethodError in Associated model's form object - ruby-on-rails

Question

I am building a project management app.
My System is like- A project has many features, A feature has many tasks.
And the routes.rb is defined as
resources :projects do
resources :features do
resources :tasks
end
end
The first level , that is project to feature is working fine for new feature form , but when I try to implement new tasks form as ->
<%= form_for([#feature, #feature.tasks.build], class: "form-group row") do |form| %>
<%= form.label :name %>
<%= form.text_field :name, required:true, class: "form-control" %>
<%= form.submit class: "btn btn-primary m-2" %>
<% end %>
Now its showing error as
Here is my models->
class Task < ApplicationRecord
belongs_to :feature
end
class Feature < ApplicationRecord
belongs_to :project
has_many :tasks
end
And the controller for tasks looks like->
class TasksController < ApplicationController
before_action :set_feature
def new
#task = #feature.tasks.new
end
def create
#task = #feature.tasks.new(task_params)
if #task.save
redirect_to project_features_path
else
render :new
end
end
def edit
end
def update
if #task.update(task_params)
redirect_to project_feature_tasks_path
else
render :edit
end
end
def complete
#task.update(completed: true)
redirect_to project_feature_tasks_path
end
def destroy
#feature.task.destroy
redirect_to project_feature_tasks_path
end
private
def set_feature
#feature = Feature.find(params[:feature_id])
end
def task_params
params.require(:task).permit(:name,:completed, :project_id,:feature_id)
end
end
Any help is very much appreciated - I am stuck with this error for days now.

Answer 1

If you try running $ rails routes you can see why your current routes are failing you.
Prefix Verb URI Pattern Controller#Action
project_feature_tasks GET /projects/:project_id/features/:feature_id/tasks(.:format) tasks#index
POST /projects/:project_id/features/:feature_id/tasks(.:format) tasks#create
new_project_feature_task GET /projects/:project_id/features/:feature_id/tasks/new(.:format) tasks#new
edit_project_feature_task GET /projects/:project_id/features/:feature_id/tasks/:id/edit(.:format) tasks#edit
project_feature_task GET /projects/:project_id/features/:feature_id/tasks/:id(.:format) tasks#show
PATCH /projects/:project_id/features/:feature_id/tasks/:id(.:format) tasks#update
PUT /projects/:project_id/features/:feature_id/tasks/:id(.:format) tasks#update
DELETE /projects/:project_id/features/:feature_id/tasks/:id(.:format)
You would have to call:
form_for([#project, #feature, #feature.tasks.build], ...) do |form|
A better idea is to unnest the routes. You can do this by using the shallow option:
resources :projects do
resources :features, shallow: true do
resources :tasks
end
end
Or you can do it like so if you for some reason want to keep the member routes (show, edit, update, destroy) for features nested:
resources :projects do
resources :features
end
resources :features, only: [] do
resources :tasks
end