Edit report at https://bugs.php.net/bug.php?id=39579&edit=1
ID: 39579
Updated by: ni...@php.net
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: Bug
Package: Variables related
Operating System: FreeBSD 6.1
PHP Version: 5.2.0
Block user comment: N
Private report: N
New Comment:
@radamanf: Stop shouting. Shouting does not help.
I agree that this behavior ('foo' == 0) is counter-productive. I think most
people would agree on that. But even if everyone agrees that it's the wrong
behavior, changing it isn't so easy. Changing this behavior will probably break
existing software.
If you really want to change this, then there is only one way: Make the change
and then test a shitload of code against it. See how many tests will fail in
major PHP projects and how easy things are to fix.
If you can provide sufficient data that this change (which goes rather deep
into the core semantics of the language) won't affect existing projects
heavily, then I see no problem with doing it.
Previous Comments:
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[2013-02-14 17:14:35] radamanf at gmail dot com
Related To: Bug #39579
------------------------------------------------------------------------
[2013-02-14 17:14:35] radamanf at gmail dot com
This is a epic FAIL in pure logic of comparing formats not having explicitly
defining them, whole beauty of PHP disappear! This is BROKEN LOGIC.
Connected BUGS
Bug #44990
Bug #39579
Different people are coming across this BUG and thinking the same as me, so
please CHANGE your documentation, it's WRONG! Who is this "GENIES" to make
possible converting String to Integer NOT INT TO STRING!
Guys, I'm very disappointed! :)
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[2012-08-01 10:31:16] v dot picture at free dot fr
Hi, I'm wondering why this comparison should be evaluated in a numeric context
and not a string context, after all
there is no loss with string casting whereas there is a huge risk of doing
mistakes with numeric casting:
(string) 0 => "0"
(string) 42.5 => "42.5"
(int) "test" => 0
But ok, let's say it's a normal behavior.
"If you compare a number with a string or the comparison involves numerical
strings, then each string is converted to
a number"
Then why would PHP decide to do that in a string context ? I mean, when I
compare two strings I don't expect PHP to
convert everything to numbers !
"10" == "1e1" => true
Sorry folks, this really seems like a string context to me.
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[2006-11-22 11:36:19] m...@php.net
It's not a problem -- it's a feature, and it's documented at the address I've
just quoted, which describes evaluation of a string in any numeric context.
------------------------------------------------------------------------
[2006-11-22 11:14:47] iain at workingsoftware dot com dot au
it's not the behaviour of how a string is cast to an integer that i'm talking
about, but if i have a comparison:
if($value == Class::CONSTANT)
and the class constant is a string, it's not immediately apparent that if
$value == 0 then this will evaluate to true. maybe warning is too strong, but a
notice might be good in the event that a non-strict == operation returns true
because one of the operands is 0 and the other operand is a value that
evaluates to 0 when cast as an int.
anyway, i guess if php has been around for this long without anyone mentioning
it yet ... i mean, this is the first time i've come across the problem. if a
notice had been emitted it would have been a time saver.
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