3.0 Custom exception handling method name

[glafarge]

I used a vendor API (=Mailchimp) which had it's own Exception naming conventions.

I want to change how Mailchimp_List_AlreadySubscribed (exception) is rendered and I used a custom exception handler.

namespace App\Error;

use Cake\Error\ExceptionRenderer;

class AppExceptionRenderer extends ExceptionRenderer
{
    public function mailchimpListAlreadySubscribed($error)
    {
        return 'Oops the user is already subscribed to the list !';
    }
}

Never called.

When I saw how CakePHP gets the method name, I understand why it doesn't works...

cakephp/src/Error/ExceptionRenderer.php

Line 201 in e236933

$baseClass = substr($baseClass, 0, -9);

    protected function _method(\Exception $exception) {
        list(, $baseClass) = namespaceSplit(get_class($exception));
        $baseClass = substr($baseClass, 0, -9);
        $method = Inflector::variable($baseClass) ?: 'error500';
        return $this->method = $method;
    }

It searches for mailchimpListAlreadyS() method instead of the complete name because of substr().

What do you think about this ?
I have already made a change to it but I don't know if it's a good approach.

[jadb]

Closing as #5771 is now open.