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To: Steven Wade <stevenwadejr@gmail.com>,
 PHP Internals <internals@lists.php.net>
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Date: Thu, 6 Feb 2020 22:33:34 +0000
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Subject: Re: [PHP-DEV] [RFC - discussion] __toArray()
From: php.lists@allenjb.me.uk (AllenJB)

What happens if I perform array-like operations on an object 
implementing __toArray() from this RFC?

For example:

$obj["foo"] = 42;

or:

$bar = $obj["foo"];

(Imagine these examples are perhaps within a loop iterating a collection 
of objects)

Which operations do and do not work? As they'd be operating on a new 
from-cast array, I assume they would not be able to effect the original 
object (properties), but is this what people expect?

What I'm trying to get at here is: Does this RFC create opportunities 
for bugs arising because objects are accidentally treated as arrays and 
users would no longer receive any kind of warning or error from such 
code when they would have in the past?

(Aside: Could this get even more interesting where a loop involving 
references being (ab)used is involved? Experienced developers know you 
should avoid references, but many newer developers use them - either 
through misunderstanding the language or copying others and not actually 
understanding what they're doing. While, anecdotally from helping others 
in various channels, this occurs less than it did in the PHP 5 era, it 
does still occur.)

If so, I believe this is obviously bad. If not, I believe this is also 
bad because the above example do not work as someone (particularly newer 
users) might expect. The language is creating something which sometimes, 
maybe, acts like an array, but not always.


The other problem I have with this type of magic on objects is that 
people don't usually mean "to array", they mean "to array for specific 
purpose" - eg. "to array for database record" or "to array for API 
output". Using a magic method for this obfuscates the purpose of the 
returned array and could lead to problems, such as accidental data 
leakage, from cross-usage.

AllenJB


On 04/02/2020 13:03, Steven Wade wrote:
> Hi all,
>
> I’d like to officially open my __toArray() RFC <https://wiki.php.net/rfc/to-array> up to discussion. I’ve delayed changing the status until I had more time to respond to the discussion, but since it’s been brought up again <https://externals.io/message/108351>, I figured now is the best time.
>
> https://wiki.php.net/rfc/to-array <https://wiki.php.net/rfc/to-array>
>
> Cheers,
>
> Steven Wade