Bugsnag shouldn’t report silenced errors

[gchtr]

Expected behavior

When error reporting is set to Warning, then Bugsnag shouldn’t report silenced PHP errors. For example, the following code shouldn’t report a warning:

@unlink( '/path/to/inexistent/file.jpg' );

Observed behavior

Bugsnag reports PHP warnings for code that is silenced with an @.

Steps to reproduce

1. Put this code in functions.php of your theme and reload the page.

   @unlink( '/path/to/inexistent/file.jpg' );

2. See error in the dashboard.

I’m not sure, but this logic might be what causes the warning to be reported:

https://github.com/bugsnag/bugsnag-php/blob/e50a26a5535f5e4ffb386a449710f2ce9c050287/src/Configuration.php#L543-L550

PHP’s documentation for error control operators clearly states:

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 @.

In shouldIgnoreErrorCode(), the function might return without checking error_reporting(). So I’m guessing that this is why silenced errors are reported.

Version

Bugsnag: 1.3.1
WordPress: 5.0.3

Additional information

Tell me if you need some more information.

[Cawllec]

Thanks for the report @gchtr. It's an issue where if you've set an errorReportingLevel, we only check that, and not the error_reporting method. We're aware of the issue and will release a fix as soon as we can.

As a temporary fix, you could create a callback function that returns false if error_reporting is 0.
Something like:

$bugsnagWordpress->setBeforeNotifyFunction(function ($report) {
  if (error_reporting() === 0) {
    return false;
  }
});

[fiskhandlarn]

Any news on when bugsnag/bugsnag-php#537 can be made available in bugsnag-wordpress (i.e. bump the bundled https://github.com/bugsnag/bugsnag-php/ from 2.10.0 to at least 3.18.0)?

[mattdyoung]

Hi @fiskhandlarn

bugsnag-wordpress will need a fair amount of rework to pull in bugsnag-php v3.x. We don't have a timeframe yet but hope to do this when priorities allow.

For the time being the suggested workaround of modifying the behavior in a callback should still work.

[fiskhandlarn]

if anyone's interested, i'm using this to at least silence lines that begins with @:

add_action('plugins_loaded', function() {
    global $bugsnagWordpress;
    if (isset($bugsnagWordpress) && is_callable([$bugsnagWordpress, 'setBeforeNotifyFunction'])) {
        try {
            // Bugsnag reports PHP warnings for code that is silenced with an @.
            // https://github.com/bugsnag/bugsnag-wordpress/issues/35#issuecomment-457130639
            $bugsnagWordpress->setBeforeNotifyFunction(function ($report) {
                $stacktrace = $report->stacktrace->toArray() ?? null;
                if ($stacktrace) {
                    $line = trim($stacktrace[1]['code'][$stacktrace[1]['lineNumber']] ?? '');
                    if (strpos($line, '@') === 0) {
                        return false;
                    }
                }
            });
        } catch (\BadMethodCallException $e) {
            // bugsnag api key probably not set, ignore
        }
    }
});