I need to call session() if I want to be able to use old() in the forms.

[daljit3]

---

name: Bug report

Describe the bug
If you fill only username and leave password empty below, then the testone() below doesn't retain the entered username. However, if I just call the session() method in the testtwo(), then it keeps the username.

It's a bit confusing for a new user as it's not suggested in the documentation.

Is this the correct behaviour?

public function testone()
{
	//This test fails to keep the old value
	$data_post = $this->request->getPost();
	$username = $data_post['username'] ?? '';
	$password = $data_post['password'] ?? '';
	
	if($username == '' || $password == '')
	{
		return redirect()->back()->withInput();
	}
	echo view('login');
}

public function testtwo()
{
	//This test preserves the old value
	
	$session = session();
	
	$data_post = $this->request->getPost();
	$username = $data_post['username'] ?? '';
	$password = $data_post['password'] ?? '';
	
	if($username == '' || $password == '')
	{
		return redirect()->back()->withInput();
	}

	echo view('login');
}

//Views/login.php
<form method="post" class="text-center border border-light p-5">
	<p class="h4 mb-4">Sign in</p>

	<input type="text" name="username" id="defaultLoginFormEmail" class="form-control mb-4" placeholder="Username" value="<?= old('username') ?>" />
	<input type="password" name="password" id="defaultLoginFormPassword" class="form-control mb-4" placeholder="Password" value="">

	<!-- Sign in button -->
	<button class="btn btn-info btn-block my-4" type="submit">Sign in</button>
</form>

CodeIgniter 4 version
Latest CI4 Beta.1

[cesar-calvo]

Session must be initiated to with() and withInput() methods works!

<?php namespace App\Controllers;

class Auth extends \CodeIgniter\Controller
{
    public function __construct()
    {
        $this->session = service('session');
    }

    public function login()
    {
        //getPost() method return NULL if variable is not set
        if($this->request->getPost('username') == '' || $this->request->getPost('password') == '')
        {
            return redirect()->back()->withInput();
        }
        echo view('login')
    }

}