fix: use first exception in exceptionHandler()

[kenjis]

Description
Fixes #7339

Now the last Exception is shown, but showing the first Exception helps for debugging.
This PR shows the first Exception.

<?php

namespace App\Controllers;

use CodeIgniter\HTTP\RequestInterface;
use CodeIgniter\HTTP\ResponseInterface;
use Psr\Log\LoggerInterface;

class Tests extends BaseController
{
    public function initController(RequestInterface $request, ResponseInterface $response, LoggerInterface $logger)
    {
        // Do Not Edit This Line
        parent::initController($request, $response, $logger);

        $this->xx(); // Call to undefined method App\Controllers\Tests::xx()
    }

    public function __destruct()
    {
        dd($this->info); // Undefined property: App\Controllers\Tests::$info
    }

    public function index()
    {
    }
}

Before:

$ php public/index.php tests


[ErrorException]

Undefined property: App\Controllers\Tests::$info

at APPPATH/Controllers/Tests.php:21

Backtrace:
  1    APPPATH/Controllers/Tests.php:21
       CodeIgniter\Debug\Exceptions()->errorHandler(2, 'Undefined property: App\\Controllers\\Tests::$info', '/Users/kenji/work/codeigniter/official/CodeIgniter4/app/Controllers/Tests.php', 21)

  2    SYSTEMPATH/CodeIgniter.php:490
       App\Controllers\Tests()->__destruct()

  3    SYSTEMPATH/CodeIgniter.php:368
       CodeIgniter\CodeIgniter()->handleRequest(null, Object(Config\Cache), false)

  4    FCPATH/index.php:67
       CodeIgniter\CodeIgniter()->run()

After:

$ php public/index.php tests


[Error]

Call to undefined method App\Controllers\Tests::xx()

at APPPATH/Controllers/Tests.php:16

Backtrace:
  1    SYSTEMPATH/CodeIgniter.php:907
       App\Controllers\Tests()->initController(Object(CodeIgniter\HTTP\CLIRequest), Object(CodeIgniter\HTTP\Response), Object(CodeIgniter\Log\Logger))

  2    SYSTEMPATH/CodeIgniter.php:490
       CodeIgniter\CodeIgniter()->createController()

  3    SYSTEMPATH/CodeIgniter.php:368
       CodeIgniter\CodeIgniter()->handleRequest(null, Object(Config\Cache), false)

  4    FCPATH/index.php:67
       CodeIgniter\CodeIgniter()->run()

Checklist:

• Securely signed commits
• Component(s) with PHPDoc blocks, only if necessary or adds value
• Unit testing, with >80% coverage
• User guide updated
• Conforms to style guide

[paulbalandan]

Would it better to display all exceptions in the stack? Something like:

[Exception 1]
Text
Backtrace:
...

Caused by:

[Exception 2]
Text
Backtrace:
...

Caused by:
...
...

[kenjis]

I thought about that, but I think one would be simpler.

By the way, I don't know why the first exception is now hidden in the sample code.
Why is it so?

[paulbalandan]

Not sure about that. Maybe because PHP still called __destruct before calling the exception handler?

[kenjis]

Maybe because PHP still called __destruct before calling the exception handler?

It seems like that.
I guess that if a class fails to instantiate, the destructor is called.