Edit report at https://bugs.php.net/bug.php?id=39579&edit=1
ID: 39579
Comment by: v dot picture at free dot fr
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:
*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 !
Previous Comments:
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[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($var) to something other than
boolean or changing the way that types are cast when comparing a string and an int to each other OR;
b) Changing the value that a string is cast to when cast as either a boolean or an int, to be
consistent
Both of these changes would wreak unspeakable havoc on existing applications, and probably
wouldn't make any tremendous difference overall to the uninitiated.
HOWEVER, I do think that it would be acceptable to emit a NOTICE when a string is implicitly cast to
(int) during a comparison using == and suggesting they use an explicit type cast or strict equals to
suppress the notice (see my comments above).
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[2013-10-22 18:42:18] mirroredfate at gmail dot com
> It's not a problem -- it's a feature, and it's documented at the address
> I've just quoted
And I could document a webserver sometimes crashing when you click a button and call it a
"feature", but that doesn't make it so.
This is clearly counter-intuitive behavior and should be beaten to death with an iron rod after
being water-boarded. It is terrible. If you are defending this, you should probably take a long,
hard look at your life and your principles.
Making zero equal any string is just wrong. I completely goes against how PHP operates in every
other instance, and no doubt causes developers no end of distress and frustration. It's a
feature like how getting beaten up in a dark alley is a feature of that alley.
This needs to be fixed, people.
------------------------------------------------------------------------
[2013-07-03 00:36:56] iain at workingsoftware dot com dot au
Hey xtalviper, the reason it does this is because in the case of:
if($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
------------------------------------------------------------------------
[2013-02-15 10:08:27] radamanf at gmail dot com
Hi Nick, Thanks for your answers on both related bugs.
I apologize for my expressions.
But I'm still thinking this bug should be fixed one day, maybe on later day when a few
backwards compatible bugs will be found, so it makes more sense to fix it as a bunch. I hear that
PHP 5.3 was breaking release and some old code was not working since, it was the right time to fix
this bug.
The general logic should be: Convert less complicated variable type into more complicated type, so
convert Int up to String not bringing String down to Int. This need to be universal and according to
KISS logic. If geeks need to use strings for octal or hexadecimal then they know what they are doing
and need to cast such string as Int! To bring string down to Int.
v dot picture at free dot fr ->
"
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.
"
Someone need to write a great exploit to hack into eCommerce shops and produce unseen damage across
the Globe :) then this will not be funny at all.
I wish this patch could happen one day! Temporarily it could be at least a Warning, Iain suggested
to give a notice, but I believe this bug got a great hidden potential.
------------------------------------------------------------------------
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