Edit report at https://bugs.php.net/bug.php?id=64320&edit=1
ID: 64320 User updated by: php at richardneill dot org Reported by: php at richardneill dot org Summary: Proposal: deprecate the "leading 0 means octal" behaviour -Status: Feedback +Status: Closed Type: Feature/Change Request Package: Math related Operating System: All PHP Version: 5.4.12 Block user comment: N Private report: N New Comment: You know, that bug has annoyed me for ages, since I got badly bitten by it about 7 years ago. In the meantime, I think it's been fixed! At any rate, I now agree with you that the current behaviour is correct, and that: PHP now treats strings with leading zeros (eg "0123") as decimal (123), rather than octal, even when automatically casting them. The documentation (in the sections: integers, casting) could perhaps be more explicit, given that: $a = 0x123; $b = "0x123" + 0; // $a and $b are equal $c = 0123; $d = "0123" + 0; // $c and $d are not equal. Sorry for the confusion - my bad. Previous Comments: ------------------------------------------------------------------------ [2013-02-28 17:14:36] ni...@php.net Could you maybe provide a testcase for the behavior you are referring to? I tried out the following and "010" wasn't interpreted as octal in any case: var_dump((int) "010", intval("010"), "010" == 8); // Outputs: int(10) int(10) bool(false) 010 is only treated as an octal if you write it out plainly (in the source code), like $foo = 010; ------------------------------------------------------------------------ [2013-02-28 13:41:48] php at richardneill dot org Description: ------------ PHP assumes that a string with a leading zero should be interpreted as octal. In my experience, this is almost never useful, desirable, or intentional, however, it is a frequent trap for the beginner (or more experienced programmer), especially when parsing user-submitted data. The only reason for this behaviour seems to be historical, and compatibility with strtol(). When non-programmer humans write numbers with leading zeros, they don't usually mean base 8. My proposal is: 1. Introduce a new string format, 0o#### (letter o), to explicitly mean "this is an octal number". This is similar to the recent introduction of 0b#### for binary numbers. [This part should be simple to do, and would also make the intentional use of octal notation explicit, increasing code-readability] 2. Add an option to raise E_NOTICE any time a number is implicitly interpreted as octal (for example "$x = 0100"). 3. In a few years time, (PHP 7?), it may finally be possible to change the default behaviour. Test script: --------------- Here's an illustration of a naive program that has data-dependent bugs that are really hard to track down. $mass_kg = "0.314" //user-submitted data, known to begin "0." $mass_g = substr ($mass_kg, 2); Yes, this is a silly thing to write. But it's a nasty trap for the unwary. The above example does what is expected, and might pass many tests. But if the user subsequently enters $mass_kg = "0.031", this will turn into 25 grams, not 31 grams. As a result, we have created a very subtle and hard to find bug. ------------------------------------------------------------------------ -- Edit this bug report at https://bugs.php.net/bug.php?id=64320&edit=1