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Date: Fri, 7 Mar 2014 16:58:51 +0100
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To: Julien Pauli <jpauli@php.net>
Cc: Tjerk Meesters <tjerk.meesters@gmail.com>, PHP Internals <internals@lists.php.net>
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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 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.

-- 
Etienne Kneuss

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