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To: "Sherif Ramadan" <theanomaly.is@gmail.com>, "Anthony Ferrara"
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Cc: "Igor Wiedler" <igor@wiedler.ch>, "PHP Internals"
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Date: Mon, 24 Dec 2012 18:58:38 -0000
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Subject: Re: [PHP-DEV] PHP-5.5 unpack change broke pecl/pear
From: glopes@nebm.ist.utl.pt ("Gustavo Lopes")

On Mon, 24 Dec 2012 12:13:35 -0000, Anthony Ferrara <ircmaxell@gmail.com=
>  =

wrote:

> You're right. It does break BC, but this was a bug fix.
>> https://bugs.php.net/bug.php?id=3D61038
>>
>> The behavior is incorrect in that regard.
>
> However in this case that *bug* does have fairly significant BC
> implications.
>
> In fact, how I read the specification is that the original binary form=
at  =

> is NULL padded, not the resulting string. Therefore, you could make th=
e
> argument that the new behavior is wrong.

The Perl docs say:

> =C2=B4A=C2=B4 strips trailing whitespace and nulls, =C2=B4Z=C2=B4 stri=
ps everything after  =

> the first null, and =C2=B4a=C2=B4 returns data with no stripping at al=
l.

PHP docs are silent on this matter.

Yes, PHP does not have to follow Perl's specification, but
1) PHP's pack/unpack was clearly modeled after Perl
2) is desirable to have close semantics to Perl's implementation as it  =

benefits those who use both languages like the submitter of #61038

Given 1), perl's docs and implementation and the absence of evidence to =
 =

the contrary (like PHP tests and documentation), it's clear to me that  =

pre-5.5 behavior is a bug (no quotes).

Now you may think that the cost of fixing this bug does not cover its  =

benefits, possibly given alternative solutions.

What I can say about that is that I think that the alternative solution =
 =

that you propose (switching the behavior of "a" and "Z") would be tradin=
g  =

a relatively minor short term inconvenience (this will affect several  =

orders of magnitude less people than the htmlentities() change in 5.4) f=
or  =

one that will exist indefinitely and I consider that a poor choice.

-- =

Gustavo Lopes