From:
Operating system:
PHP version: 5.4.0
Package: *General Issues
Bug Type: Bug
Bug description:User-defined error handler run despite at sign (@) error control operator
Description:
------------
The at sign operator allows to "ignore" error messages, as explained in
http://ca3.php.net/manual/en/language.operators.errorcontrol.php
When prepended to an expression in PHP, any error messages that might be
generated by that expression will be ignored.
However, as reported in #61091, user-defined error handlers registered with
set_error_handler() are nevertheless run when @ is used, which often causes
such messages to show, as in the below example, where a custom error
handler is used to customize the display of error messages.
As http://ca3.php.net/manual/en/language.operators.errorcontrol.php#98895
and http://ca3.php.net/manual/en/language.operators.errorcontrol.php#85042
show, this problem is not new. This behavior appears to be by design, and
might be wanted in some cases.
Therefore, please either:
Stop calling user-defined error handlers when suppressing errors. This
needs serious consideration for backwards-compatibility.
Allow specifying whether user-defined error handlers should be called when
suppressing errors.
Make the documentation reflect the current state of things.
Alternatively, if the documentation of the @ operator isn't amended because
custom error handlers are considered a corner case, then the
set_error_handler() documentation should warn developers tempted to use
custom error handlers that they are non-standard, not
recommended/supported, and try to explain the pitfalls. In short, tell
developers they should only use a custom error handler if they know what
they're doing.
However, this alternative should be avoided since set_error_handler() is
already used in several applications whose developers didn't receive the
warning.
Test script:
---------------
<?php
function myErrorHandler($errno, $errstr) {
switch ($errno) {
case E_USER_ERROR:
echo "<b>My ERROR</b> [$errno] $errstr<br />\n";
echo " Fatal error on line $errline in file $errfile";
echo ", PHP " . PHP_VERSION . " (" . PHP_OS . ")<br
/>\n";
echo "Aborting...<br />\n";
exit(1);
break;
case E_USER_WARNING:
echo "<b>My WARNING</b> [$errno] $errstr<br />\n";
break;
case E_USER_NOTICE:
echo "<b>My NOTICE</b> [$errno] $errstr<br />\n";
break;
default:
echo "Unknown error type: [$errno] $errstr<br />\n";
break;
}
}
// function to test the error handling
function scale_by_log($vect, $scale)
{
if (!is_numeric($scale) || $scale <= 0) {
trigger_error("log(x) for x <= 0 is undefined, you used: scale =
$scale", E_USER_ERROR);
}
if (!is_array($vect)) {
trigger_error("Incorrect input vector, array of values expected",
E_USER_WARNING);
return null;
}
$temp = array();
foreach($vect as $pos => $value) {
if (!is_numeric($value)) {
trigger_error("Value at position $pos is not a number, using 0
(zero)", E_USER_NOTICE);
$value = 0;
}
$temp[$pos] = log($scale) * $value;
}
return $temp;
}
$a = array(2, 3, "foo", 5.5, 43.3, 21.11);
/* Value at position $pos is not a number, using 0 (zero) */
scale_by_log($a, M_PI);
@scale_by_log($a, M_PI);
set_error_handler("myErrorHandler");
@scale_by_log($a, M_PI);
?>
Expected result:
----------------
Notice: Value at position 2 is not a number, using 0 (zero) in
/var/www/atoperator.php on line 42
Call Stack:
0.0005 339192 1. {main}() /var/www/atoperator.php:0
0.0005 339836 2. scale_by_log(array (0 => 2, 1 => 3, 2 => 'foo',
3 => 5.5, 4 => 43.3, 5 => 21.11), 3.1415926535898)
/var/www/atoperator.php:55
0.0006 340648 3. trigger_error('Value at position 2 is not a
number, using 0 (zero)', 1024) /var/www/atoperator.php:42
Actual result:
--------------
Notice: Value at position 2 is not a number, using 0 (zero) in
/var/www/atoperator.php on line 42
Call Stack:
0.0005 339192 1. {main}() /var/www/atoperator.php:0
0.0005 339836 2. scale_by_log(array (0 => 2, 1 => 3, 2 => 'foo',
3 => 5.5, 4 => 43.3, 5 => 21.11), 3.1415926535898)
/var/www/atoperator.php:55
0.0006 340648 3. trigger_error('Value at position 2 is not a
number, using 0 (zero)', 1024) /var/www/atoperator.php:42
<b>My NOTICE</b> [1024] Value at position 2 is not a number, using 0
(zero)<br />
--
Edit bug report at https://bugs.php.net/bug.php?id=61747&edit=1
--
Try a snapshot (PHP 5.4): https://bugs.php.net/fix.php?id=61747&r=trysnapshot54
Try a snapshot (PHP 5.3): https://bugs.php.net/fix.php?id=61747&r=trysnapshot53
Try a snapshot (trunk): https://bugs.php.net/fix.php?id=61747&r=trysnapshottrunk
Fixed in SVN: https://bugs.php.net/fix.php?id=61747&r=fixed
Fixed in SVN and need be documented: https://bugs.php.net/fix.php?id=61747&r=needdocs
Fixed in release: https://bugs.php.net/fix.php?id=61747&r=alreadyfixed
Need backtrace: https://bugs.php.net/fix.php?id=61747&r=needtrace
Need Reproduce Script: https://bugs.php.net/fix.php?id=61747&r=needscript
Try newer version: https://bugs.php.net/fix.php?id=61747&r=oldversion
Not developer issue: https://bugs.php.net/fix.php?id=61747&r=support
Expected behavior: https://bugs.php.net/fix.php?id=61747&r=notwrong
Not enough info: https://bugs.php.net/fix.php?id=61747&r=notenoughinfo
Submitted twice: https://bugs.php.net/fix.php?id=61747&r=submittedtwice
register_globals: https://bugs.php.net/fix.php?id=61747&r=globals
PHP 4 support discontinued: https://bugs.php.net/fix.php?id=61747&r=php4
Daylight Savings: https://bugs.php.net/fix.php?id=61747&r=dst
IIS Stability: https://bugs.php.net/fix.php?id=61747&r=isapi
Install GNU Sed: https://bugs.php.net/fix.php?id=61747&r=gnused
Floating point limitations: https://bugs.php.net/fix.php?id=61747&r=float
No Zend Extensions: https://bugs.php.net/fix.php?id=61747&r=nozend
MySQL Configuration Error: https://bugs.php.net/fix.php?id=61747&r=mysqlcfg