I recently (2 weeks ago) utilized ArrayObject in a project. Works very well for certain use cases. I hear some of the negatives presented in the comments. Right, array_* functions don’t work. OK, so…use ArrayObject for what it is useful for and skip it when it fails to be useful :)

Here you say:
“when you execute $a = $b, the value of $b is copied, and then assigned to $a”. But this is correct for scalar values only, and is wrong for objects, resources and arrays.
I said, “$a = $b does not copy the object, but copies the reference to the object”. The article you link to is nice, but does not cure the flimsiness of your blogpost.

Call it “semantics”. Talking about content, meaning and understanding. People too often tend to ignore it. I can’t see, how copy-on-write and copy-on-assignment could be considered to share the same “bottom line behaviour”.

http://blog.libssh2.org/index.php?/archives/51-Youre-being-lied-to..html

So what you’re arguing here is that PHP handles arrays in a particular fashion, and only duplicates the data when you read/write to the array? So the bottom line behavior is the same? Sounds like we’re arguing semantics.

That’s not correct:
If $b is an object, $a = $b does not copy the object, but copies the reference to the object.
If $b is an array, $a = $b does not copy the array, but copies the reference to the array. Then, when either $a or $b is writing to the array, the array is copied:
<?php
$foo = array();
$bar = $foo; // both variables referencing the same array

// reading the array through $bar or $foo reads the same array!

// copy on write:
$bar[] = '';
// now there are two arrays in memory,
// one for $foo; one for $bar.

Your other points about ArrayObject are valid; you would have to typehint for ArrayObject instead of Array. There are inconsistencies in the PHP API, which are extremely frustrating but a part of how PHP works.

Andrei, I’m not sure what you’re looking for here. The 6th paragraph does in fact express that there is a ticket, and explains that the array_* functions don’t work as you would expect. I’m not about to advocate that people go vote up a ticket just because I’d like to see it resolved; that’s not professional in my opinion.

Besides that ArrayObject is not supported by PHP’s array-functions, it does not pass an array-typehint (nor does an array pass an ArrayObject-typehint).

IMHO ArrayObject is massively overestimated (and – as a concrete class – depending on it should be avoided).

If I had my way I’d have all the array functions take ArrayObjects and treat them like arrays; I voted up the change request put in by Christian Wenske.