how to update nested attribute in form - ruby-on-rails

Question

I wanna update the nested attribute but failed, for example there is a Article, and a book has many comments. when I find the comment I have written has some mistakes, so I wanna modify it.
here is my code.
In code_snippet.rb:
class CodeSnippet < ApplicationRecord
has_many :annotations, dependent: :destroy
accepts_nested_attributes_for :annotations ,update_only: true ,reject_if: :all_blank, allow_destroy: true
end
In annotation.rb:
class Annotation < ApplicationRecord
belongs_to :code_snippet
end
In code_snippet_controller.rb:
def edit
#code_snippet = CodeSnippet.find(params[:id])
end
def update
#code_snippet = CodeSnippet.find(params[:id])
if #code_snippet.update(code_snippet_params)
redirect_to #code_snippet
else
render 'edit'
end
end
private
def code_snippet_params
params.require(:code_snippet).permit(:snippet)
end
In annotation.rb:
def edit
#code_snippet = CodeSnippet.find(params[:code_snippet_id])
#annotation = #code_snippet.annotations.find(params[:id])
end
def update
#code_snippet = CodeSnippet.find(params[:id])
#annotation = #code_snippet.annotations.find(params[:id])
if #annotation.update(annotation_params)
redirect_to #code_snippet
else
render 'edit'
end
end
In 'views/code_snippets/show.html.rb'
<div>
<h2>Annotations</h2>
<%= render #code_snippet.annotations %>
</div>
In 'views/annotations/_annotation.html.erb'
<p>
<strong>User:</strong>
<%= annotation.user %>
</p>
<p>
<strong>Line:</strong>
<%= annotation.line %>
</p>
<p>
<strong>Body:</strong>
<%= annotation.body %>
</p>
<p>
<%= link_to "Edit", edit_code_snippet_annotation_path(annotation.code_snippet,annotation) ,controller: 'annotation'%>
</p>
In 'views/annotations/edit.html.erb':
<%= form_for(#code_snippet) do |f| %>
<%= f.fields_for :annotation,method: :patch do |builder| %>
<p>
<%= builder.label :user %><br>
<%= builder.text_field :user %>
</p>
<p>
<%= builder.label :line %><br>
<%= builder.text_field :line %>
</p>
<p>
<%= builder.label :body %><br>
<%= builder.text_area :body %>
</p>
<p>
<%= builder.submit %>
</p>
<% end %>
<% end %>
what I wanna update the annotation without change the codesnippets. what should I do to change my code.

Answer 1

So.... There's a lot going on here so I'm going to start by suggesting a careful look at the docs
Firstly, let's look at your form:
CodeSnippet has_many :annotations
So your fields_for statement should be for :annotations, not :annotation. The fields for statement also should not take a method options key.
Next your code_snippets_controller:
As indicated by the docs, the parameter sent back from the nested attributes form will be under the key: annotations_attributes and will contain a hash of arrays.
You need to allow this attribute, and any attribute you wish to pass onto the annotation model with strong parameters:
params.require(:code_snippet).permit(annotations_attributes: [:some, : permitted, :params])
I believe this is all you need to get your example working. But, if you run into more troubles, I recommend a spending some quality time with a few binding.pry statements to introspect on the actual behaviour of your code.