(Firstly: I hasten to add that the "weirdness" is "weird to me". It might be completely predictable to everyone else in the PHP world).
This is a follow-on from my earlier article "PHP: accessing an undefined array element yields a notice. Or does it? WTF, PHP?". Now before I start: Kalle Sommer Nielsen has come back to me in a comment on that article and mentions it's expected behaviour, and explained it... but I don't quite follow yet. I'm hoping some ensuing experimentation will cast some light on the scene.
My next variation of this has me scratching my head more. Well: it's demonstrating the same thing, but perhaps more clearly.
<?php
echo PHP_EOL . "Test with array" . PHP_EOL;
$a = [1, 2, 3];
var_dump($a[0]);
var_dump($a[0]['id']);
var_dump($a[0][0]['id']);
var_dump($a[0]['id'][0]);
echo PHP_EOL . "Test with int" . PHP_EOL;
$i = 1;
var_dump($i['id']);
var_dump($i[0]['id']);
var_dump($i['id'][0]);
echo PHP_EOL;
echo PHP_EOL . "Test with string" . PHP_EOL;
$s = '1';
var_dump($s['id']);
var_dump($s[0]['id']);
var_dump($s['id'][0]);
This yields:
C:\temp>php test.php
Test with array
C:\temp\test.php:6:
int(1)
C:\temp\test.php:7:
NULL
C:\temp\test.php:8:
NULL
C:\temp\test.php:9:
NULL
Test with int
C:\temp\test.php:13:
NULL
C:\temp\test.php:14:
NULL
C:\temp\test.php:15:
NULL
Test with string
PHP Warning: Illegal string offset 'id' in C:\temp\test.php on line 21
PHP Stack trace:
PHP 1. {main}() C:\temp\test.php:0
Warning: Illegal string offset 'id' in C:\temp\test.php on line 21
Call Stack:
0.0002 356384 1. {main}() C:\temp\test.php:0
C:\temp\test.php:21:
string(1) "1"
PHP Warning: Illegal string offset 'id' in C:\temp\test.php on line 22
PHP Stack trace:
PHP 1. {main}() C:\temp\test.php:0
Warning: Illegal string offset 'id' in C:\temp\test.php on line 22
Call Stack:
0.0002 356384 1. {main}() C:\temp\test.php:0
C:\temp\test.php:22:
string(1) "1"
PHP Warning: Illegal string offset 'id' in C:\temp\test.php on line 23
PHP Stack trace:
PHP 1. {main}() C:\temp\test.php:0
Warning: Illegal string offset 'id' in C:\temp\test.php on line 23
Call Stack:
0.0002 356384 1. {main}() C:\temp\test.php:0
C:\temp\test.php:23:
string(1) "1"
C:\temp>
OK, so here I factor-out the top-level array from the mix. That test was always referring to the first element of the array, which is just the integer 1, so we might as well just test with that. Needless to say, there's the same results as with the first array element. But I still don't get it. What is using array notation to dereference an integer supposedly doing? It's a non-sensical operation, as far as I understand things. And if it is a nonsensical operation: it should error.
For completeness I also try a variation with a string "1". This does error like I'd expect. Well: it gives a warning and then returns an inappropriate (IMO) result anyhow. This is probably PHP doing it's combo of telling me I did it wrong but then going ahead and guessing what I meant anyhow. Grrr.
I'm gonna mess around with de-referencing integers some more when I get a moment, and try to work out WTF.
Righto.
--
Adam
