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Date: Fri, 7 Mar 2014 17:12:17 +0100
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To: Julien Pauli <jpauli@php.net>
Cc: Tjerk Meesters <tjerk.meesters@gmail.com>, PHP Internals <internals@lists.php.net>
Content-Type: multipart/alternative; boundary=089e014940784eecc004f4068689
Subject: Re: [PHP-DEV] [PR 614] ArrayObject and isset() / empty() behaviour
From: colder@php.net (Etienne Kneuss)

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On Fri, Mar 7, 2014 at 4:58 PM, Etienne Kneuss <colder@php.net> wrote:

>
>
> On Fri, Mar 7, 2014 at 3:15 PM, Julien Pauli <jpauli@php.net> wrote:
>
>> On Fri, Mar 7, 2014 at 11:14 AM, Tjerk Meesters
>> <tjerk.meesters@gmail.com> wrote:
>> > Hi,
>> >
>> > I come across the following bug: https://bugs.php.net/bug.php?id=66834
>> >
>> > With an extended ArrayObject instance, the behaviour of `isset()` and
>> > `empty()` is as follows:
>> >
>> > 1. Call `static::offsetExists()`
>> > 2. If return value is truthy, then
>> >   a. isset() returns true
>> >   b. empty() returns false
>> >   c. spl_array_has_property() returns true
>> >
>> > However, if the ArrayObject instance is not overridden:
>> >
>> > 1. Fetch value (either via string or long key)
>> > 2. If key is found, then:
>> >   a. isset() returns false if value is `null`, true otherwise.
>> >   b. empty() returns true if value is truty, false otherwise.
>> >   c. spl_array_has_property() returns true
>> >
>> > That's counterintuitive, so my patch addresses this by also calling
>> > `offsetGet()` if applicable. I wanted to bring this to the attention of
>> the
>> > group first, because it may affect performance to achieve this goal:
>>
>
> I have always been annoyed by this dichotomy between offsetExists() which
> is functionning like array_key_exists() and isset() which is returning
> false on defined, null values. Especially since isset() calls
> offsetExists() only.
>
> I would argue that the correct way to fix it is to have isset()/empty()
> call offsetGet() as well if it exists. So in that sense I feel like your
> patch is not addressing the right issue. In a sense ArrayObject does a hack
> to circumvent that in the first place, and you are trying to fix the hack
> to make it look more like what is supposed to happen.
>
>
Apart from this underlying "design" issue, it is true an overridden version
of ArrayObject is not functionally equivalent to the original class. So it
seems worth fixing independently from this hack.
-- 
Etienne Kneuss

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