Bug #62097 [Wfx->Csd]: New behavior of string == has a compatibility problem

From: Date: Tue, 07 Oct 2014 23:25:20 +0000
Subject: Bug #62097 [Wfx->Csd]: New behavior of string == has a compatibility problem
References: 1  Groups: php.bugs 
Request: Send a blank email to php-bugs+get-187937@lists.php.net to get a copy of this message
Edit report at https://bugs.php.net/bug.php?id=62097&edit=1

 ID:                 62097
 Updated by:         stas@php.net
 Reported by:        kazuo at o-ishi dot jp
 Summary:            New behavior of string == has a compatibility
                     problem
-Status:             Wont fix
+Status:             Closed
 Type:               Bug
 Package:            Scripting Engine problem
 Operating System:   Gentoo Linux
 PHP Version:        5.4.4RC1
 Assigned To:        stas
 Block user comment: Y
 Private report:     N

 New Comment:

Automatic comment on behalf of cataphract
Revision: http://git.php.net/?p=php-src-security.git;a=commit;h=acd711685a592c52be200e248154283c6c49c9f8
Log: Fixed bug #62097


Previous Comments:
------------------------------------------------------------------------
[2012-06-15 00:42:42] hholzgra@php.net

Ok, so the problem is not only with leading zeros but also with trailing decimals
, eg.

  "12345678901234567890" == "12345678901234567890.0"

will now return false while it returned true before (that is the essence of the pgsql example
further above).

This in combination with NUMERIC or DECIMAL fixed point values in databases does indeed look like a
more likely BC issue to run into than the leading zero case. 

On the other hand we're in "never compare floats for equality" land here ...

------------------------------------------------------------------------
[2012-06-01 21:26:20] stas@php.net

OK, we got trolls here, so I'm blocking comments to it. If you want to continue 
discussion, you're welcome to raise it on the list.

------------------------------------------------------------------------
[2012-06-01 20:44:31] steve at home dot com

kazuo at o-ishi dot jp:

Just don't expect the PHP type system to make any sense, it's easier than trying to
understand it at this point. Obviously the developer you are talking to does not understand this
issue. If you want to have reliable behavior, PHP is not for you (unless you stick to a single
version and work out the oddities).

------------------------------------------------------------------------
[2012-05-31 06:23:30] stas@php.net

I believe I did explain the reason and I believe this is reason enough. If you 
disagree, please feel free to raise it on internals list and if enough of the 
community supports you it will be reversed. So far I did not hear any more 
complaints about it. I think it is clear that there is a disagreement between us 
about how to handle this, and more discussion is not going to bring any 
improvement. I am closing this bug, if you feel more discussion is required 
please raise it on the list.

------------------------------------------------------------------------
[2012-05-31 02:36:51] kazuo at o-ishi dot jp

I have shown test cases that work on released version 5.4.3
but not work on developing version.

Now, YOU need explain real merit of this backward incompatible change.
md5() is not enough reason, because it should always be compared by
=== instead of ==.

Generally, at the case when new behavior (memcmp for large
value) is acceptable, we can and we should just use ===.


> If you have such code 
> sample and can explain what data it accepts, what it does and why it relies on 
> string comparisons cutting numbers, please do so. Your database example is 
> missing data, so I can not see what is going on there and why you think it works 
> differently in 5.4.3 and 5.4.4.

(I'm sorry but I cannot understand what you say in this two sentence.
Could you explain detail?)


In JPY (Japan Yen), we normally use it in integer (e.g. 100 yen).
But sometimes it take fraction (e.g. foreign exchange 1 USD = 78.80 JPY).
So database column type with fraction is reasonable.
And set to / get from the column in integer form is also reasonable.

Again, I just report incompatibility from PHP 5.4.3 to PHP 5.4.4RC.

This is wrong way if you want to fix security problem, because
incompatible change makes the users difficult to migrate to new version.

------------------------------------------------------------------------


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=62097


--
Edit this bug report at https://bugs.php.net/bug.php?id=62097&edit=1


Thread (26 messages)

« previous php.bugs (#187937) next »