PHP: \Exception or Exception inside a namespace

Question

I am trying to handle some errors in my api. However I tried some so many ways to execute what it's needed to it done?

In the code i used Exception, \Exception, another class extending to Exception, "use \Exception". None of these options works. What i need to do execute the block catch?

  //Piece of source in the begin of file
    namespace Business\Notifiers\Webhook;
    use \Exception;
    class MyException extends \Exception {}

    //Piece of source from my class
    try{

        $products = $payment->getProducts();
        if(count($products) == 0)
            return;
        $flight_id = $products[0]->flight_id;
        $this->message = 'Sir, we have a new request: ';
        $products = null; //Chagind it to null to force an error..
        foreach($products as $product){

            $this->appendAttachment(array(
                'color' => '#432789',
                'text' => 
                    "*Name:* $product->name $product->last_name \n" . 
                    "*Total Paid:*  R\$$product->price\n",
                'mrkdwn_in' => ['text', 'pretext']
            ));
        }
    } catch(Exception $e){
        $this->message = "A exception occurred ";
    } catch(\Exception $e){
        $this->message = "A exception occurred e";
    } catch(MyException $e){
        $this->message = "A exception occurred";
    }

`throw new Exception('throwing an exception...');` https://secure.php.net/Exceptions — Charlotte Dunois, Oct 15 '16 at 21:11
I'm forcing the exception. I changed the $products to null, after this line im using foreach. — Guilherme Soares, Oct 15 '16 at 21:12
This does not throw an exception (or fatal error), it's a warning. `Warning: Invalid argument supplied for foreach()` — Charlotte Dunois, Oct 15 '16 at 21:13

score 22 · Answer 1 · answered Sep 12 '19 at 02:25

The accepted answer above give the real cause of the issue, but did not answer the topic

If in case someone is interested and is looking for

what is the difference between Exception and \Exception inside a namespace?

Still valid against PHP 7.3.5:

\Exception: Refer to Exception in root namespace
Exception: Refer to Exception in current namespace
PHP does not fall back to root namespace, if the class cannot be found in current name space, it emits an error.

<?php
namespace Business;
try {
    throw new Exception("X"); //  Uncaught Error: Class 'Business\Exception' not found
} catch (Exception $e) {
    echo "Exception: " . $e->getMessage();
}

<?php
namespace Business;
class Exception extends \Exception {} // means \Business\Exception extends \Exception

$a = new Exception('hi'); // $a is an object of class \Business\Exception
$b = new \Exception('hi'); // $b is an object of class \Exception

Further clarification can be found at https://stackoverflow.com/a/44867502/2511355. If you haven't extended the global Exception class, you should choose `use \Exception` — Tim Rogers, May 01 '20 at 20:57
The only thing to add: https://www.php.net/manual/en/language.namespaces.global.php — wp78de, Jan 12 '21 at 18:59

score 5 · Accepted Answer · answered Oct 15 '16 at 21:32

First of all, you need to understand the difference between an exception and an error:

Trying to foreach over a null value will not yield an exception, but trigger an error. You can use an error handler to wrap an error in an exception, as such:

<?php

function handle ($code, $message)
{
    throw new \Exception($message, $code);
}

set_error_handler('handle');

// now this will fail
try {
    $foo = null;
    foreach ($foo as $bar) {
    }
} catch(\Exception $e) {
    echo $e->getMessage();
}

However in your code, you can simply check if $products is null and if so, throw an exception:

if (!$products) {
    throw new \Exception('Could not find any products')
}
foreach($products as $product) { ...

Foreaching over a NULL value will not trigger an error. PHP throws a warning. — Charlotte Dunois, Oct 15 '16 at 21:41
Deep down, a warning is just an error with E_WARNING level. The code will work either way. You can monitor for only certain types of errors by specifying the second parameter of the set_error_handler() function - http://php.net/manual/en/function.set-error-handler.php — motanelu, Oct 15 '16 at 21:45

PHP: \Exception or Exception inside a namespace

2 Answers2