Avoid confusion with class methods and protected/private modifiers (#…

…1512)

Working on something else, I saw the following:

```ruby
  protected

  # ...

  def self.field_type
    to_s.split("::").last.underscore
  end
```

This code can lead to misunderstanding, as the `protected` modifier doesn't
apply to class methods like `self.field_type`.

On this PR, I move two such class methods behind the modifier, near the top of
the class, to avoid this confusion.

I also move three other class methods to the top of the class, as I feel class
methods should go together in general, in order to clarify interfaces and avoid
future instances of this anti-pattern.

lib/administrate/field/base.rb

@@ -16,6 +16,14 @@ def self.searchable?
         false
       end
 
+      def self.field_type
+        to_s.split("::").last.underscore
+      end
+
+      def self.permitted_attribute(attr, _options = nil)
+        attr
+      end
+
       def initialize(attribute, data, page, options = {})
         @attribute = attribute
         @data = data
@@ -24,10 +32,6 @@ def initialize(attribute, data, page, options = {})
         @options = options
       end
 
-      def self.permitted_attribute(attr, _options = nil)
-        attr
-      end
-
       def html_class
         self.class.html_class
       end
@@ -41,12 +45,6 @@ def to_partial_path
       end
 
       attr_reader :attribute, :data, :options, :page, :resource
-
-      protected
-
-      def self.field_type
-        to_s.split("::").last.underscore
-      end
     end
   end
 end

lib/administrate/field/has_one.rb

@@ -3,13 +3,6 @@
 module Administrate
   module Field
     class HasOne < Associative
-      def nested_form
-        @nested_form ||= Administrate::Page::Form.new(
-          resolver.dashboard_class.new,
-          data || resolver.resource_class.new,
-        )
-      end
-
       def self.permitted_attribute(attr, options = nil)
         associated_class_name =
           if options
@@ -24,6 +17,13 @@ def self.permitted_attribute(attr, options = nil)
         { "#{attr}_attributes": related_dashboard_attributes }
       end
 
+      def nested_form
+        @nested_form ||= Administrate::Page::Form.new(
+          resolver.dashboard_class.new,
+          data || resolver.resource_class.new,
+        )
+      end
+
       private
 
       def resolver

lib/administrate/field/polymorphic.rb

@@ -3,6 +3,10 @@
 module Administrate
   module Field
     class Polymorphic < BelongsTo
+      def self.permitted_attribute(attr, _options = nil)
+        { attr => %i{type value} }
+      end
+
       def associated_resource_grouped_options
         classes.map do |klass|
           [klass.to_s, candidate_resources_for(klass).map do |resource|
@@ -11,10 +15,6 @@ def associated_resource_grouped_options
         end
       end
 
-      def self.permitted_attribute(attr, _options = nil)
-        { attr => %i{type value} }
-      end
-
       def permitted_attribute
         { attribute => %i{type value} }
       end

lib/administrate/view_generator.rb

@@ -5,15 +5,15 @@ module Administrate
   class ViewGenerator < Rails::Generators::Base
     include Administrate::GeneratorHelpers
 
-    private
-
     def self.template_source_path
       File.expand_path(
         "../../../app/views/administrate/application",
         __FILE__,
       )
     end
 
+    private
+
     def copy_resource_template(template_name)
       template_file = "#{template_name}.html.erb"