On Thu, Nov 24, 2011 at 1:38 AM, David Muir <davidkm...@gmail.com> wrote:
> On 24/11/11 06:25, Stas Malyshev wrote:
> > Hi!
> >
> >> The only case where the 5.4 branch works differently as before if you
> >> reference a string type(int, float, etc. won't trigger this) variable
> >> using an associative index and you expect it that to be undefined
> >> variable even though that the documentation explicitly states that the
> >
> > Actually, the only change 5.4 did was to make $a['foo']['bar'] work
> > like ($a['foo'])['bar'] - i.e. chained offsets work the same way as if
> > they were applied separately. That's it. All the rest has been there
> > since forever. I can't see how one could argue it should stay this way.
> >
> > Now I'm sorry somebody used the fact that chained offsets didn't work
> > to do a check "do we have any strings there" but that's not how PHP is
> > supposed to work and it's clearly a side-effect of a bug.
>
> One thing that I wasn't aware of was the string to int conversion for
> string offsets. IMO, that should trigger a notice or something. Good to
> be reminded of though.
>
> Just to clarify, the changes introduced in 5.4 will result in the
> following:
>
> <?php
>
> $string = 'foo';
> $array = array(
> 'foo' => array(
> 'bar' => 'baz',
> //expected structure
> //'bar' => array('baz' => array('values'))
> ));
>
> var_dump(
> isset($string['foo']), //true
> isset($string[0][0]), //false, true in 5.4
> isset($array['foo']['bar'][0]), //true
> isset($array['foo']['bar']['baz']), //true
> isset($array['foo']['bar']['baz']['0']) //false, true as of 5.4
> isset($string['foo']['bar']['baz']['0']) //false, true as of 5.4
> );
>
you are missing a comma from the end of the
isset($array['foo']['bar']['baz']['0']) //false, true as of 5.4
line
isset($string['foo']['bar']['baz']['0']) //false, true as of 5.4
gives me a fatal error on 5.3 ("PHP Fatal error: Cannot use string offset
as an array" as you can't "chain" string offsets before 5.4)
> If so, then it's a major BC break.
> Maybe it's a bugfix, but it's a bugfix that allows for behaviour that
> 1. doesn't really make sense
>
I think Stas and Etienne summed up the benefits and the reason of this
change pretty much(mostly internals related).
> 2. has little to no practical benefit (when are you ever going to be
> chaining offsets on strings?)
>
I agree that there are not (m)any usecase for the ability for method
chaining in it's current form.
> 3. introduces new, hard-to-detect bugs in live code.
>
the bugs are there already(you expect an array where you get a string), it
will just fail differently.
>
> What used to be a one-liner, now effectively needs a crapload of
> boilerplate code.
>
yeah, if you can't trust the data structures in your code, then you have to
validate it.
don't forget that this bug could also bite you with 5.3:
// you expect $foo to be an array
$foo = 'string';
//this will echo 's'
echo $foo['bar'];
Personally I think that the main issue is that we silently convert
$foo['bar'] to $foo[0] for strings, which imo rarely the intended behavior
and doesn't really makes much sense (except that the offset expects the
index to be int, and this is how we type juggle between string and int), so
I think it would be a good idea to raise a notice here, so the developer
can fix his code, or add some input validation.
--
Ferenc Kovács
@Tyr43l - http://tyrael.hu
