Nest the group_children_path inside the canonical group path

app/controllers/groups/children_controller.rb

+module Groups
+  class ChildrenController < Groups::ApplicationController
+    before_action :group
+
+    def index
+      parent = if params[:parent_id].present?
+                 GroupFinder.new(current_user).execute(id: params[:parent_id])
+               else
+                 @group
+               end
+
+      if parent.nil?
+        render_404
+        return
+      end
+
+      setup_children(parent)
+
+      respond_to do |format|
+        format.json do
+          serializer = GroupChildSerializer
+                         .new(current_user: current_user)
+                         .with_pagination(request, response)
+          serializer.expand_hierarchy(parent) if params[:filter].present?
+          render json: serializer.represent(@children)
+        end
+      end
+    end
+
+    protected
+
+    def setup_children(parent)
+      @children = GroupDescendantsFinder.new(current_user: current_user,
+                                             parent_group: parent,
+                                             params: params).execute
+      @children = @children.page(params[:page])
+    end
+  end
+end

app/controllers/groups_controller.rb

@@ -59,31 +59,6 @@ class GroupsController < Groups::ApplicationController
     end
   end
 
-  def children
-    parent = if params[:parent_id].present?
-               GroupFinder.new(current_user).execute(id: params[:parent_id])
-             else
-               @group
-             end
-
-    if parent.nil?
-      render_404
-      return
-    end
-
-    setup_children(parent)
-
-    respond_to do |format|
-      format.json do
-        serializer = GroupChildSerializer
-                       .new(current_user: current_user)
-                       .with_pagination(request, response)
-        serializer.expand_hierarchy(parent) if params[:filter].present?
-        render json: serializer.represent(@children)
-      end
-    end
-  end
-
   def activity
     respond_to do |format|
       format.html
@@ -120,13 +95,6 @@ class GroupsController < Groups::ApplicationController
 
   protected
 
-  def setup_children(parent)
-    @children = GroupDescendantsFinder.new(current_user: current_user,
-                                           parent_group: parent,
-                                           params: params).execute
-    @children = @children.page(params[:page])
-  end
-
   def authorize_create_group!
     allowed = if params[:parent_id].present?
                 parent = Group.find_by(id: params[:parent_id])

config/routes/group.rb

@@ -30,6 +30,8 @@ scope(path: 'groups/*group_id',
     end
 
     resources :variables, only: [:index, :show, :update, :create, :destroy]
+
+    resources :children, only: [:index]
   end
 end
 
@@ -53,9 +55,5 @@ constraints(GroupUrlConstrainer.new) do
     patch '/', action: :update
     put '/', action: :update
     delete '/', action: :destroy
-
-    scope(path: '-') do
-      get :children
-    end
   end
 end