why devise is generating this format of confirmation URL?

devise keep on generating this format of confirmation URL

http://something.com/users/confirmation/divyanshu-rawat?confirmation_token=CV3zV1wAWsb3RokHHEKN

I don't know why it is not generating something like this.

http://something.com/users/confirmation?confirmation_token=CV3zV1wAWsb3RokHHEKN

This is how my confirmation_instructions.html.haml looks like.

%p Welcome #{@resource.first_name}!
%p You can confirm your account email through the link below:
%p= link_to 'Confirm my account', user_confirmation_url(@resource, :confirmation_token => @resource.confirmation_token)

In Devise gem, routes for confirmation are created as below,

#  # Confirmation routes for Confirmable, if User model has :confirmable configured
#  new_user_confirmation GET    /users/confirmation/new(.:format) {controller:"devise/confirmations", action:"new"}
#      user_confirmation GET    /users/confirmation(.:format)     {controller:"devise/confirmations", action:"show"}
#                        POST   /users/confirmation(.:format)     {controller:"devise/confirmations", action:"create"}

So if you want to create url like,

http://something.com/users/confirmation?confirmation_token=CV3zV1wAWsb3RokHHEKN

Use

user_confirmation_url(confirmation_token: @resource.confirmation_token)`

Instead of

user_confirmation_url(@resource, confirmation_token: @resource.confirmation_token)`

Also check routes.rb

If you want to pass user_name or name db attribute of @resource in confirmation url (as you asked by passing 'divyanshu-rawat' in your url), You can create own custom route which will point to same controller & action as below,

  # config/routes.rb
  devise_for :users

  as :user do
    get  '/users/confirmation/:name' => "devise/confirmations#show", as: 'user_confirm'
  end 

And if in your case, @resource.user_name = 'divyanshu-rawat', update confirmation_instructions.html.haml as below,

%p Welcome #{@resource.first_name}!
%p You can confirm your account email through the link below:
%p= link_to 'Confirm my account', user_confirm_url(name: @resource.user_name, confirmation_token: @resource.confirmation_token)

Which will produce url like,

http://something.com/users/confirmation/divyanshu-rawat?confirmation_token=CV3zV1wAWsb3RokHHEKN