Bug #50688 [Com]: Using exceptions inside usort() callback function causes a warning

Edit report at https://bugs.php.net/bug.php?id=50688&edit=1 ID: 50688 Comment by: m at rtin dot so Reported by: jcampbell at remindermedia dot com Summary: Using exceptions inside usort() callback function causes a warning Status: Assigned Type: Bug Package: Arrays related Operating System: Fedora Core 12 PHP Version: 5.*, 6 Assigned To: stas Block user comment: N Private report: N New Comment: I ran into a similar issue, i'm sure it'll require the same patch as it's the backtrace causing the problem but worth noting it doesn't require an exception to trigger this, just a backtrace. $ cat usort.php <?php set_error_handler(function($errno, $errstr) { $bt = debug_backtrace(); var_dump($errstr); }); $arr = [1, 2]; usort($arr, function($a, $b) use ($arr) { trigger_error('test'); return $a > $b; }); $ php usort.php string(4) "test" string(59) "usort(): Array was modified by the user comparison function" Previous Comments: ------------------------------------------------------------------------ [2013-07-09 07:21:19] jakub dot lopuszanski at nasza-klasa dot pl I'd like to add, that you do not have to throw an exception to get this warning. Mere creating it, also triggers the warning, as in: <?php function comp($a,$b){ @new Exception("dupa"); } $a =array(1,2,3); usort($a, 'comp'); var_dump($a); ?> PHP Warning: usort(): Array was modified by the user comparison function in /home/jlopuszanski/test.php on line 6 ------------------------------------------------------------------------ [2013-06-17 11:11:07] andrejs dot verza at gmail dot com Php 5.4.16 also fails with this. Still the same status for 3 and a half years old bug?! ------------------------------------------------------------------------ [2012-08-08 17:53:58] mbrowne83 at gmail dot com This will probably be obvious to most, but I just wanted to mention that you can always prefix the usort function with the @ symbol to prevent the warning...of course that would also suppress any other types of notices or warnings that might occcur anywhere within the sorting function... ------------------------------------------------------------------------ [2012-02-24 18:04:02] keith at breadvault dot com This same problem arises when using Mockery to mock the object whose method is being used by usort(), even though the method itself neither is mocked nor handles any exceptions. The proxy generated by Mockery must wrap the target class's methods with some exception-handling code. Unfortunately this forced me to code a workaround that would not use usort. My hack extracts from the objects in the array the values being sorted on, sorts that array of values using asort() (to preserve the keys), and finally rebuilds the list of objects using the keys in the order that they appear in the asorted list of values. Yuck. ------------------------------------------------------------------------ [2012-02-21 22:56:31] eric_haney at yahoo dot com It took me a while to figure out that some code called from usort was throwing, catching, and (gracefully) handling an Exception. Then I found this post. Quite frustrating. I turned off warnings with ini_set before calling usort, then turned them on again after. This is an effective workaround for now, but I'd love to clean that nastiness out of my code. It is also my opinion that usort should be allowed to change the elements in the array. EG: an instance variable of an object may be lazy-loaded as a result of a method call from within a usort callback. Should a warning really be issued in that case? ------------------------------------------------------------------------ The remainder of the comments for this report are too long. To view the rest of the comments, please view the bug report online at https://bugs.php.net/bug.php?id=50688 -- Edit this bug report at https://bugs.php.net/bug.php?id=50688&edit=1