Hi Lars and list! New facts about the strange bug initially diagnosed as array() returning NULL:
Firstly, the issue is not really about array() returning null, but about full
blown UndefinedBehavior(TM) progressively trashing local variables. It just so
happened that I noticed it first with a variable to which array() had been
assigned just before things began breaking.
Secondly, I proudly present the culprit: things break when I iterate over a
DOMNode's children *by reference* using firstChild and nextSibling:
for($child=&$node->firstChild; $child; $child=&$child->nextSibling) {
//processing...
}
No problems if iteration is done by value or by DOMNodeList (childNodes,
DOMXPath...).
HOWEVER,
I still consider this a bug because it destablizes PHP. After the evil loop
has finished, things happen that should never happen, like a variable being
NULL immediately after being assigned array().
I attach a demonstration. It is a self-contained commented script that you can
execute from command line. Also attached is output on my machine.
Best regards,
Szczepan Hołyszewski
<<attachment: testme.php>>
THE GOOD WAY (DOMNodeList):
Recursion structure:
->render()
->render()
->render()
<-
->render()
<-
<-
<-
Transformation result:
Some text.
[object type='foo' name='bar'][param name='__default_content']
Some parameter text.
Some parameter text.
[object type='bar' name='nested'][param name='__default_content']
Some nested parameter text.
Some nested parameter text.
[object type='baz' name='deeply_nested'][param
name='__default_content']
[/param][param name='bold']true[/param][/object]
More nested parameter text
More nested parameter text
[/param][/object]
[/param][/object]
Some more text
Success!
THE MIXED WAY (DOMNodeList at outermost level, then firstChild/nextSibling by
ref):
Recursion structure:
->render()
->render()
->render()
<-
->render()
<-
<-
<-
Transformation result:
Some text.
[object type='foo' name='bar'][param name='__default_content']
Some parameter text.
Some parameter text.
__default_content[param
name='__default_content']__default_content[/param][/object]
[/param][/object]
Some more text
Is it really a success?
THE EVIL WAY (firstChild/nextSibling by ref):
Recursion structure:
->render()
->render()
->render()
<-
->render()
<-
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