Launch an error with trigger_error or Exception in a different scope

Question

Suppose I have a function in a file called foo.php:

<?php
function foo() {
    trigger_error('Olá mundo!', E_USER_ERROR);
}

And in the index.php file I would use it like this:

<?php
require 'foo.php';

//Chamando erro
foo();

He’ll make a mistake like this:

Fatal error: Hello world! in /path/foo.php on line 3

However I would like to issue the trigger_error in the file I called foo();, for example, see that the path appears /path/foo.php on line 3, but what I would like to get is the way in /path/index.php on line 5 for this line is the line I called foo();.

I know I can create a custom error using echo or printf for example, only that the problem is that these custom errors do not affect the error_get_last and the error_clear_last.

I wonder if it is possible to define in a Exception for example line and error scope.

Answer 1

I found a great example in Soen which allows to somehow use inform what scope the custom method was called.

It will be necessary to use the $trace = debug_backtrace(FALSE); that lets you know where your method was called.

foo.php should look something like:

<?php
function foo() {
    //Pega o escopo de quem chamou foo();
    $trace = debug_backtrace(false);

    $message = 'Olá mundo! ' .
        sprintf('in %s on line %d Triggered', $trace[0]['file'], $trace[0]['line']);

    $trace = NULL;

    trigger_error($message, E_USER_NOTICE);
}

When running index.php:

<?php
require 'foo.php';

//Chamando
foo();

echo '<pre>';
print_r(error_get_last());
echo '</pre>';

You will get the error on the screen and can still use error_get_last() (This will vary from what type of error you are using in trigger_error or if you’re going to capture with set_handler_error), the exit will be something like this:

Notice: Hello world! in /path/index.php on line 5 Triggered in /path/foo.php online 11

Array
(
[type] => 1024
[message] => Hello world! in /path/index.php on line 5 Triggered
[file] => /path/foo.php
[line] => 11
)

Note that in the error_get_last the line the reported file is from foo.php, but you can parse in message if you need.

The idea of creating a custom error like this is to be able to create own functions and if there is any fault the script will be able to inform exactly where the method was executed, for example:

function dividir($a, $b) {
    $err = NULL;

    if (false === is_numeric($a)) {
        $err = 'Primeiro argumento é invalido';
    } else if (false === is_numeric($b)) {
        $err = 'Segundo argumento é invalido';
    } else if ($b == 0) {
        $err = 'Não pode dividir por zero';
    }

    if ($err) {
       $trace = debug_backtrace(false);

       $message = $err .
           sprintf('in %s on line %d Triggered', $trace[0]['file'], $trace[0]['line']);

       $trace = NULL;
       trigger_error($message, E_USER_NOTICE);
       return NULL;
    }

    return $a / $b;
}

In this case we have 3 possible errors, so if we use the method like this in index.php:

<?php
require 'foo.php';

echo dividir(10, 0);

We’ll have the following mistake:

Notice: Can’t divide by zero in index.php on line 4 Triggered in foo.php on line 20

Some details in this other debug_backtrace answer: /a/78168/3635