php array access on boolean

Question

I recently stumbled across the following:

<? $d=false; var_dump($d[123]); ?>

which yielded NULL, but (unexpected to me) without any notice, as for example

<? $d=array(); var_dump($d[123]); ?>

does produce the well known

Notice: Uninitialized string offset:  123 in - on line 1

What is going on here? Is there any documentation of this behavior?

That's pretty sad behaviour, if you ask me.

tacone
– tacone

2011-03-24 23:33:07 +00:00
Commented Mar 24, 2011 at 23:33 — tacone
– tacone, Commented Mar 24, 2011 at 23:33

meze · Accepted Answer · 2011-03-24 23:17:56Z

4

From here:

Accessing variables of other types (not including arrays or objects implementing the appropriate interfaces) using [] or {} silently returns NULL.

answered Mar 24, 2011 at 23:17

meze

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Community · Accepted Answer · 2017-05-23 12:11:53Z

2

I guess that is what you would call undefined behaviour.

It makes sense, as a boolean can not have an offset.

error_reporting(E_ALL);
$d = TRUE; 
var_dump($d[0]);

This also produces NULL (if FALSE was coerced to an empty string, it would make sense that TRUE would be 1).

Plus what meze said :)

edited May 23, 2017 at 12:11

CommunityBot

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answered Mar 24, 2011 at 23:16

alex

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Comments

NikiC · Accepted Answer · 2011-03-24 23:20:33Z

1

Quick look at the source code shows that this is expected behavior. But don't ask me why they did it this way...

answered Mar 24, 2011 at 23:20

NikiC

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