# error suppression operator and set_error_handler - php

Question

I am following good programming practices and I am logging the PHP errors to file instead of displaying it to user. I use set_error_handler() for that.
Now the problem. For example, I have somewhere:
#file_exists('/some/file/that/is/outside/openbasedir.txt');
But despite the error suppression operator, the error message logs. I don't want that. I want suppressed errors not to pass to my error handler.

Answer 1

This answer applies at PHP 7:
The # operator temporarily sets error_reporting to 0, so you can test the value of error_reporting in your error handler:
if (error_reporting() == 0)
return;
Or even better, log only error types that are in error_reporting:
$error_reporting = error_reporting();
if ( !($error_reporting & $errno) )
return;
Also take a look at the log_errors and error_log options, for automatically logging errors to a file or to syslog.

Answer 2

Solution that also works for PHP 7
According to the PHP docs:
If you have set a custom error handler function with set_error_handler() then it will still get called, but this custom error handler can (and should) call error_reporting() which will return 0 when the call that triggered the error was preceded by an #.
Source: http://php.net/manual/en/language.operators.errorcontrol.php
So you can use the following code in your error handler:
function exception_error_handler($errno, $errstr, $errfile, $errline ) {
if (error_reporting() == 0) {
/// # sign temporary disabled error reporting
return;
}
throw new ErrorException($errstr, 0, $errno, $errfile, $errline);
}
set_error_handler("exception_error_handler");

Answer 3

From manual:
Warning Prior to PHP 8.0.0, the error_reporting() called inside the
custom error handler always returned 0 if the error was suppressed by
the # operator. As of PHP 8.0.0, it returns the value E_ERROR |
E_CORE_ERROR | E_COMPILE_ERROR | E_USER_ERROR | E_RECOVERABLE_ERROR |
E_PARSE.
This means that solutions from other answers will not work :(
The #-operator became completely unusable imho.
To disable errors you will have to do the following:
error_reporting(0); // disable
try {
$res = 10/0;
} catch (Throwable){
$res = false;
}
error_reporting(-1); // enable

Answer 4

PHP8 behavior has changed and checking error_reporting() == 0 in the error handler no longer works. The way to check for errors suppressed with # in PHP8 is as follows:
function errorHandler($err_severity, $err_msg, $err_file, $err_line)
{
// Skip errors suppressed by #
if (!(error_reporting() & $err_severity)) {
return true;
}
// Error handling here
return false;
}

Answer 5

You should actually avoid usage of # operator. First of all, it is slow, and I would as far as to call it harmful.
What you should have instead is in php.ini file have two line:
error_repoting = E_ALL | E_STRICT
display_errors = Off
... or , if you do not have access to the php.ini file , then at the top of index.php (or any other bootstrap file) you should add :
error_reporting( E_ALL | E_STRICT );
ini_set('display_errors', 0);

Answer 6

PHP8 code 4437 for #
function myErrorHandler(int $errno, string $errstr, ?string $errfile, ?int $errline) : void {
if (error_reporting() !== 4437)
{
......
}
}
set_error_handler("myErrorHandler", E_ALL);