Req #39579 [Com]: Comparing zero & string values in boolean comparison has unexpected behaviour

Edit report at https://bugs.php.net/bug.php?id=39579&edit=1 ID: 39579 Comment by: mirroredfate at gmail dot com Reported by: iain at workingsoftware dot com dot au Summary: Comparing zero & string values in boolean comparison has unexpected behaviour Status: Not a bug Type: Feature/Change Request Package: Variables related Operating System: FreeBSD 6.1 PHP Version: 5.2.0 Block user comment: N Private report: N New Comment: There is another option: when a string casting to an int fails inside a conditional statement, the conditional evaluates to false. >Both of these changes would wreak unspeakable havoc on existing applications, and probably >wouldn't make any tremendous difference overall to the uninitiated. Really? I am genuinely curious as to why anyone would actually use '(0 == 'string') to determine if a string could not be cast to an int. This seems kind of like a "rip the band-aid off" situation to me. Let people know a few patches ahead of time, then go ahead with the change. After all, PHP had no problem removing JSON. The fact that it could cause problems is one of the biggest reasons why one should not design stupid, counter-intuitive stuff the first place. Previous Comments: ------------------------------------------------------------------------ [2013-10-22 21:33:09] v dot picture at free dot fr *Sighh* Do I have to open a separate bug report ? Everybody seems to ignore the comment I made about a year ago about the fact that: ((string) "10" == (string) "1e1") => true So okay, ("test" == 0) => true, let's pretend it's a feature (and insult the intelligence of about every PHP developer) but there is no way that a comparison between two strings could end up being evaluated as numbers ! There is clearly something very wrong with that ! ------------------------------------------------------------------------ [2013-10-22 20:45:43] iain at workingsoftware dot com dot au Hi mirroredfate at gmail dot com, I really don't think this should be changed. Take a look at my note above about why this happens, it's because in one case the string is cast as boolean, and in another case cast as an int. Changing this would require either: a) Changing the type that you cast a variable to when you do if($var) to something other than boolean or changing the way that types are cast when comparing a string and an int to each other OR; b) Changing the value that a string is cast to when cast as either a boolean or an int, to be consistent Both of these changes would wreak unspeakable havoc on existing applications, and probably wouldn't make any tremendous difference overall to the uninitiated. HOWEVER, I do think that it would be acceptable to emit a NOTICE when a string is implicitly cast to (int) during a comparison using == and suggesting they use an explicit type cast or strict equals to suppress the notice (see my comments above). ------------------------------------------------------------------------ [2013-10-22 18:42:18] mirroredfate at gmail dot com > It's not a problem -- it's a feature, and it's documented at the address > I've just quoted And I could document a webserver sometimes crashing when you click a button and call it a "feature", but that doesn't make it so. This is clearly counter-intuitive behavior and should be beaten to death with an iron rod after being water-boarded. It is terrible. If you are defending this, you should probably take a long, hard look at your life and your principles. Making zero equal any string is just wrong. I completely goes against how PHP operates in every other instance, and no doubt causes developers no end of distress and frustration. It's a feature like how getting beaten up in a dark alley is a feature of that alley. This needs to be fixed, people. ------------------------------------------------------------------------ [2013-07-03 00:36:56] iain at workingsoftware dot com dot au Hey xtalviper, the reason it does this is because in the case of: if($string) then the string is cast to a boolean. If you do: if($int == $string) then the string is cast to an int. You can see this more clearly by doing this: <?php $boolstring = (boolean)"string"; $intstring = (int)"string"; var_dump($boolstring); var_dump($intstring); ------------------------------------------------------------------------ [2013-07-02 21:31:57] xtalviper at yahoo dot com Here's the basic problem of logic that doesn't follow for me: If I do if(0) { //...is false, this will never run } and I do if("string") { //...is true, will always run } Then how the hell can true == false ------------------------------------------------------------------------ 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=39579 -- Edit this bug report at https://bugs.php.net/bug.php?id=39579&edit=1