Rails session after migrate from PHP (improved)

previusly I make a post for Session Logic for User Verification in Rails Migration. Now the improvement version following advice of the comments is here.

The problem was the use of `` for executing in shell on a RoR application when making the log in. I remove it and change for system method.

module Shared
  extend ActiveSupport::Concern

  def password_regex
    /
      \A # The string must
        (?=.*[a-z]) # contain at least 1 lowercase alphabetical character
        (?=.*[A-Z]) # contain at least 1 uppercase alphabetical character
        (?=.*[0-9]) # contain at least 1 numeric character
        (?=.*[!@#$%^&*]) # contain at least one special character
        .{8,}   # Be eight characters or longer
      \z
    /x
  end
end

class SessionsController < ApplicationController
  include Shared

  layout 'modal-wrapper'

  def new
    @user = User.new
  end

  def create
    @user = User.find_by(username: username)

    if valid_params?(password)
      session[:user_id] = @user.id
      redirect_to root_path
    else
      flash[:error] = 'Invalid user or password.'
      redirect_to login_path
    end
  end

  private

  def legacy_authenticate(pass_plain)
    php_file = 'app/scripts/legacy_authenticate.php'

    if pass_plain =~ password_regex
      system('php', php_file, pass_plain, @user.password_php)
    else
      false
    end
  end

  def valid_params?(pass_plain)
    if @user&.password_php
      legacy_authenticate(pass_plain)
    elsif @user&.password_digest
      @user.authenticate(pass_plain)
    else
      false
    end
  end

  def username
    params[:user][:username]
  end

  def password
    params[:user][:password]
  end
end

legacy_authenticate.php

$password = $argv[1];
$hased_password = $argv[2];

if (password_verify($password, $hased_password)) {
  exit(0);
} else {
  exit(1);
}

the form that call the method

<%= form_for(@user, html: { class: 'log-form' }) do |f| %>
  <%= f.text_field :firstname, placeholder: 'First Name' %>
  <%= f.text_field :lastname, placeholder: 'Last Name' %>
  <%= f.text_field :username, placeholder: 'Username', required: true %>
  <%= f.email_field :email, placeholder: 'Email', required: true %>
  <%= f.password_field :password, placeholder: 'Password', required: true %>
  <%= f.password_field :password_confirmation, placeholder: 'Confirm Password', required: true %>
  <%= f.submit 'Log Up', class: 'btn btn-submit' %>
<% end %>

the unit test with 0 failures

require 'test_helper'

class SessionsControllerTest < ActionDispatch::IntegrationTest
  setup do
    @user = users(:one)
  end

  test 'should get new' do
    get login_path
    assert_response :success
  end

  test 'should login' do
    post login_path, params: { user: { username: @user.username, password: 'MyString#123' } }
    assert_response :redirect
    assert_redirected_to root_path
  end

  test 'should logout' do
    delete logout_path
    assert_response :redirect
    assert_redirected_to root_path
  end
end

and the tested data yml file

one:
  username: MyString
  email: [email protected]
  password_php: $2y$10$FYJ5PvFRPaFWWZPhFYlxEuiETZwlk5PmoehlOiR93r3.4M3gU8QVy
  password_digest: <%= BCrypt::Password.create('MyString#123') %>

Fell free to check the other post, all the modification were following the advice of J_H including the writing of this post