"an uninitialized array"? i don't see anything like that in your example.
there's just one nonexistent (null, if you must) variable. no array.

$a is an unitialized variable. It is not an empty variable ($a = "").

It is declared but not initialized. It has no value since the function returns nothing.

The problem is that PHP cannot tell that $a is supposed to be an array since $a has no value or content whatsoever.

What is the documented/expected behaviour for foreach on "null" arrays?

PHP has not problems with statements such as:

echo "$a";

So I don't see why it should have a problem with:

foreach ($a as $val) {};

Actaully I *do* understand why it is a problem :) I just would like it to suggest that foreach be able to handle null arrays. It would be *such* a nice feature ;)

if you insist on neglectful coding, lower your error_reporting level.

Neglectful coding? Why do you consider it neglectful coding if I do this for an array but good coding for a string? PHP treats null strings as empty strings, why doesn't it do the same for arrays?

All I want to know is, what is the documented behaviour for foreach on a null array. If there is no documented behaviour, let's add to the documentation. Something like:

"foreach will fail on an unitialized (null) array".

I had assumed that since PHP is usually treats null strings as empty strings it would do the same with null arrays. I was wrong. I tried to find documentation on what foreach will do in the case of a null array and could not find any.

I agree with you that this is neglectfull coding. It would be nice if there was documentation to back it up :)

FYI: I clearified this in the manual, it will show up in a few days online.

Derick

I second jc. It would be nice not to have to do if ( is_array() ) before every 
foreach(), like you don't have to with while(), when the variable is null.

Often that points to a bug. If you are ok with it, just cast it. No need for an 
is_array() check. eg.

foreach( (array)$a as $val ) ...

I found this idea somewhere on the net, thanks, it's pretty neat, still, it was a 
surprise to find out this is how foreach() behaves after years of using while() 
to loop through an array of database results.