Reply to Re: [PHP] Assistance debugging php 5.x.x

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Posted by "Eric" on 11/22/05 22:37

That's just one of the problems, it's about a project with over tens of
thousands lines of code. As I said before, I don't know whats the exact
cause. There are so many variables that contribute to this issue and of most
of them I don't understand why they contribute. However, I'm convinced the
php compiler screws up "really" bad. Now I have to find out why it screws
up, to be able to file a complete bug-report or to find a work around.

As posting code isn't an option I will try to explain the issue more
thoroughly, tomorrow, I'll discuss the possibility of access to one of our
development servers with my employer.

A more thorough explanation:

As I said before, I have a very complex model of objects. First, I will
describe the piece of the model thats involved and how it works.

We have object A, B and C, they are children of each other in this order
Also we have property objects P1, P2 and PX P1 handles textbased property
changes, P2 and PX represent other types of properties, which types is not
interesting, the way they handle input is the same as defined in the parent
class P, the only difference is how they visually represent theirselfs.

Object A has properties:
(int) status
(array) properties
(object) B

Object B has properties:
(string) title
(array) properties
(object) C

Object C has properties:
(array) properties

Each object as a "properties" array. These arrays contain the objects P1, P2
and/or PX. When object A and B wakeup (in reversed order ofcourse) they both
call a function, giving themselve ($this) as parameter. This function,
checks the P-objects in the properties array, for changed values. If a value
is changed, the function will change the value on the object.

For example:
Object B has a P1 property with the name "title" in it's properties array.
The P1 object get's on wakeup a new value from $_POST or whatever, puts this
value in it's "value" property and sets it's "changed" flag.
Now Object B wakes up and calls "the function", this functions loops through
the properties array and sees the P1 object with name "title" has it's
"changed" flag set. Now, the function copies the value from the P1 object to
the "title" property of Object B

So far so good, no errors there however, I'm doing some strange to the
model, call me stupid, but it just was de easiest way to fix this as Object
C handles to visual representation:

Object A has a PX object for it's state
Object B has a P1 object for it's title
Object C doesn't have any property objects (yet, perhaps future types of C
will)

Now Object B has set its "C" child and want C to have it's parental
properties so they can be displayed.
Object B creates references in the properties array of C to all the
properties of A and B, this is no problem as Object C doens't call "the
function" on wakeup so it won't do anything with the properties values and
even if it did, I really wouldn't care if C's nonexisting "state" or "title"
got set.

This all still works fine.

Now, Object B get's a new property of type P2, Object B doesn't care about
it's value, but has to initially set it. After it's set you might see P2 as
a "read-only" property object.
Still no issue, the P2 object is nicely, visually represented and we don't
care if it's value would change, Object B doesn't use a property with the P2
object name.

I repeated this trick and added another P2 object. Everything seemed fine
but then, when the P1 title object from Object B got it's value changed, an
error was generated: Object A noticed it's "state" property object PX
doens't exist and tries to add a new one to it's properties array. However,
this is no longer an array (which generated the error in the first place).
Objects B title get's changed correctly. My prove for php screwing up is the
following:

I "never", reset the properties array, I just don't (which is proven by
ZendPlatform)

seccond: my error handler, displays backtraces of errors, and the backtrace
just didn't make sense. I have a "helper function" to add property objects
to the properties array of objects, the error was generated in this
function. De backtrace gave me a correct line-number for the error, a
correct filename for the error, but an incorrect function name, it repeated
the Object A function instead of showing the name of "helper function".

Third: The issue seems only to occur when P1 changes and that magical third
property is of type P2 (that the 2nd property is also P2 doesn't seem to
mather also their order don't mather) and the name of this third property
contains something like "keyword". (original name "ssl_keywords" but
"keyword" and even "keywoord" caused an error while "key" didn't) (when
using ZendPlatform, the name of the key doesn't matter anymore, the new
value of the P1 object "title" seems to leak into another not related array
and everything else seems to work fine. However, this script, with these
parameters can't be debugged with ZendPlatform, as httpd will segfault, all
other scripts, even this, without that "title" parameter debug just fine)

The fourth reason is even more vague. In the beginning I solved the above
issue quite fast, by just "trying" something. I got bored and wasn't really
looking into the issue as I thought it was a stupid mistake by my own
making. I accidentally fixed the issue by letting "the function" (the one
that applies properties objects values to an object) work on references in
the foreach loop that looped through the properties array (
foreach($object->properties as $object) --> foreach($object->properties as
&$object) )
I did not thrust this fix, as it didn't seem related enough and even more
when you realize that objects in php5 always are references, zo putting that
& sign there seems a bogus to me.
Then again, at that time everything seemed to work.... not! Something else
began to screw, Object A again. In the real-life situation, Object A may
contain multiple Bs, during wakeup, it loops through it's Bs for
maintenance. The array for these B's is an associative one, where the keys
are the language that the Bs represent. Now the code looks like this:

$keys=array_keys($this->B);
foreach($keys as $key) {
// First statement
// Seccond statement
}

In the real-life situaties, there is just one B with key "Nederlands" which
is "Dutch" in dutch. In the first statement, Object A takes Object Bs title,
similiar to this:
$this->title=$this->B[$key]->title;
Works fine, now the secconds statement is executed, A tries to copy the path
to the icon of B, similiar to this:
$this->icon=$this->B[$key]->icon;
This statement fails telling me the element "Nederlancs" doesn't exists.
This is not a typo, the key mysterialy changed to "Nederlancs"! The "d"
became a "c".

Enough prove for me, however, there is still the problem of finding the
cause and a solution.

I'm going to double check if everything I said above is correct and I will
try to create simple reproduce code in order to pinpoint the cause, however,
if the problem is subject to specific "keynames" I think there is a lot more
to the issue than meets the eye. So other parts of my code may be involved.

If anyone is still interested in helping me, please let me know, tell me
what you need, what you intend to check, a guess about the cause of the
issue?

Thank you!
Eric van Blokland

"Jay Blanchard" <jay.blanchard@THERMON.com> wrote in message
news:0CEC8258A6E4D611BE5400306E1CC9270915AB01@smtmb.tmc.local...
> [snip]
> This is "globally" what happens. If you're insterested in this issue,
> willing to help me and if you think yourself to be cappable of helping me.
> Please contact me by responding to this post or contact me directly:
> [/snip]
>
> There are several on this list who are willing and capable of helping. Put
> it out here on the list, you'll get a better response. Let's see the code.

[Back to original message]


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