Why the show method is called when I try to access to my login view?

I'm learning Rails and I'm trying to do a login feature.

When I try to access to my users/login view, I get this :

I don't understand why the show method is called.

Here is my routes:

Rails.application.routes.draw do
  resources :comments
  resources :advertisements
  resources :users
  get 'users/login' => 'users#login', as: 'login'
  post 'users/login' => 'users#check', as: 'check'
  delete 'users/logout' => 'users#logout', as: 'logout'
end

Here is my controller:

class UsersController < ApplicationController
  before_action :set_user, only: [:show]

  # GET /users
  # GET /users.json
  def index
    @users = User.all
  end

  # GET /users/1
  # GET /users/1.json
  def show
  end

  def login
  end

  def check
    @current_user = User.where(name: params[:name], password: params[:password]).first
    if @current_user
      session[:user_id] = @current_user.id
      flash[:info] = "You're connected !"
      redirect_to root_path
    else
      session[:user_id] = nil
      flash[:info] = "Connection failure"
      redirect_to login_path
    end
  end

  def logout
    session[:user_id] = nil
    flash[:info] = "You're disconnected!"
    redirect_to root_path
  end

  private
    # Use callbacks to share common setup or constraints between actions.
    def set_user
      @user = User.find(params[:id])
    end

    # Never trust parameters from the scary internet, only allow the white list through.
    def user_params
      params.require(:user).permit(:name, :password, :role)
    end
end

Here is my index view:

<%= link_to 'Sign up', new_user_path %>
<%= link_to 'Sign in', login_path %>

Did I miss something?

because you are declaring the users as a resource in your routes, your app thinks that your are trying to acces the user with id 'login'.
when you declare the resource, you get urls like:

users#index => 'users'

users#show => 'users/1'

in that way, your login url is colliding with your resources, i usually create a diferent url like '/login' to prevent this to happen

Fernando is right.
Please move your custom routes above resources so it won't interfere with resources generated routes

  get 'users/login' => 'users#login', as: 'login'
  post 'users/login' => 'users#check', as: 'check'
  delete 'users/logout' => 'users#logout', as: 'logout'
  resources :users

A better way to do this would be to use REST to model sessions as a resource instead of bloating your users controller with a bunch of non-restful (and vague) routes.

Start by setting up ActiveModel::SecurePassword so that you're not storing passwords in plaintext which is a very bad practice.

class SessionsController < ApplicationController
  # GET /users/login
  def new
  end

  # POST /users/login
  def create
    if @user = User.find_by(params[:email]) && @user.authenticate(params[:password])
      session[:user_id] = @user.id
      redirect_to root_path, success: 'You have been signed in.'
    else
      # don't tell the user if the email was in fact valid 
      # to avoid enumeration attacks
      render :new, error: 'Invalid email or password'
    end
  end

  # DELETE /users/logout   
  def destroy
    session.delete(:user_id)
    redirect_to root_path, info: 'You have been signed out.'
  end
end

If you want to create vanity routes like /users/login instead of just resource :session, only: [:new, :create, :destroy] you can do it by:

get '/users/login' => 'session#new', as: :login
post '/users/login' => 'session#create'
delete '/users/logout' => 'session#destroy', as: :logout

# this has to come after
resources :users

You can also use collection to generate routes on the collection instead of a member in resources:

resources :users do
  collection do
    get :login, to: 'session#new', as: :login
    post :login, to: 'session#create'
    delete :logout, to: 'session#destroy', as: :logout
  end
end

But that will generate the named helpers users_login_path instead of just login_path.

You don't have to use a goofy /check path as the new and create routes are differentiated by the HTTP verb.

You can setup the form with:

# app/views/sessions/new.html.erb
<h1>Log in</h1>
<%= form_with(url: login_path, method: :post) do |f| %>
  <div class="field">
    <%= f.label :email %>
    <%= f.email_field :email %>
  </div>
  <div class="field">
    <%= f.label :password %>
    <%= f.password_field :password %>
  </div>
  <%= f.submit %>
<% end %>

And a button to logout:

<%= button_to logout_path, method: :delete %>

you have resources :users above get 'users/login' => 'users#login', as: 'login' and it defines route: GET users/:id and links it with show action in your controller. When you go to users/login rails will look for first matching route in your routes.rb file and it will be show action and login will be interpreted as id param.