[Resolved] 1 != 1 !!! What?

[davidjam]

OK I have been testing this script for the past 2 hours, and now I come to php builder for help.

if(!$$key->db || $$key->db != $query_table) {continue;}

$$key->db (in this scenario) is 1. It indicates the data source for that particular form element. It could just as well be 2 or 3 or however many tables I reference on a given page.

$query_table is merely a function argument which in this case is also 1

So a simplification of the code would be:

if(!1 || 1 != 1) {continue;}

So, theoretically, the loop should not continue because the condition will not be true.

But here's the kicker. It works if I add a die() statement:

if(!$$key->db || $$key->db != $query_table) {die(); continue;}

😕

[mrhappiness]

if(!$$key->db || $$key->db != $query_table) {
  echo 'inside:<br />';
  echo '$$key->db is: -'.$$key->db.'-';
  echo '<br />';
  echo '$query_table is: -'.$query_table.'-<br />';
}
echo 'outside:<br />';
echo '$$key->db is: -'.$$key->db.'-';
echo '<br />';
echo '$query_table is: -'.$query_table.'-<br />';

output?

[mtmosier]

Can you provide more code? What comes after this line? What do you expect to happen?

But here's the kicker. It works if I add a die() statement:

Please define "it works". You want it to die and it does? Or are you saying it doesn't enter the if statement?

[davidjam]

assuming when you say "outside" that you mean outside the if() (and not the loop)...

btw thanks for the reply. 🙂

Outside the if() both variables == 1

But the moment I put a die(with variables) in the if(), so I can see what their respective values are, then the script starts working properly again?!? (therefore preventing me from seeing the values)

So, out of curiosity, why did you have me test the variables inside and outside the if()?

[davidjam]

Originally posted by mtmosier
Can you provide more code? ... are you saying it doesn't enter the if statement?

That is correct. It doesn't enter the if() statement when I include a die(), but otherwise it does. Here is more code:

function load($query_table=1,$query_id="") {
	global $elements; // elements includes: username, password, password_verify and email_address_1.
	foreach($elements as $type=>$values) {
		foreach($values as $key=>$value) {
			if($key == "password" || $key == "password_verify") {continue;}
			global $$key;
			//die($$key->db . " and the query table is: " . $query_table); // this is the "outside" test I have been using
			// here is the problem line:
			if(!$$key->db || $$key->db != $query_table) {continue;}

		.. other n/a code .. 

		$result[] = $key;
	}
}
// $result *should* contain an array of the elements (username and email address)
$query_string = implode(",",$result); 

.. rest of function ..
}

Essentially I want to build a string of the columns for a database insert (i.e. $query_string == "username, email_address_1")

[mtmosier]

Please give us the actual output mrhappiness asked for, once with the die and once without.

Oh, and just replace your current if statement with all the code he provided as is.

[davidjam]

I have provided that output information in my second post. But here it is, per your instructions:

outside:
$$key->db is: -1-
$query_table is: -1-
outside:
$$key->db is: -1-
$query_table is: -1-

outside twice for the two elements: username and email address. Which proves this: for both elements the property db == 1. BTW this above code was run without the 'continue'. Is it possible that there is a bug in php where in some instances it executes a continue wrongly?

[mtmosier]

When you gave the output the first time you summarized it, and weren't specific on things like whether the word "inside" was ever outputed, or how many times it printed out.

So the if doesn't get executed in this code. Am I correct in saying that this if statement is exactly the same as yours, save the contents? If you add the continue back in (after all the echo lines inside the if) do you get the "inside" section outputted?

It's always possible for there to be a bug, just unlikely. You can seach the php bug tracking system to find out if any such bug was reported for your version of php.

[davidjam]

Thanks MT. 1st question: yes, it's the same as the if() that mr h posted. 2nd question: yes, I was finally able to get the 'inside' stuff outputted and as you can see continue is still there.

First here's the code (adapted so I could see the inside info):

foreach($values as $key=>$value) {
	global $$key;
	$test .= 'outside if() (for '.$key.'): $$key->db is: -'.$$key->db.'- <br/>';
	if(!$$key->db || $query_table != $$key->db) {
		$test .= 'inside if() (for '.$key.'): $$key->db is: -'.$$key->db.'- <br/>';
		continue;}
	..
}

Result:

outside if() (for username): $$key->db is: --
inside if() (for username): $$key->db is: --
outside if() (for email_address_1): $$key->db is: --
inside if() (for email_address_1): $$key->db is: --

OK, so no values show up there at all!

So I just add this debug die() in the above code, like this:

foreach($values as $key=>$value) {
	global $$key;

// added this:
die($key . " --> value for db --> " . $$key->db);

$test .= 'outside if() (for '.$key.'): $$key->db is: -'.$$key->db.'- <br/>';
if(!$$key->db || $query_table != $$key->db) {
	$test .= 'inside if() (for '.$key.'): $$key->db is: -'.$$key->db.'- <br/>';
	continue;}
..
}

Result:

username --> value for db --> 1

(btw I have to leave my workstation until tomorrow. Thanks for the help. Hope to hear from you again by morning!)

[mtmosier]

Wow, that makes no sense whatsoever. I mean obviously "inside" will print if $$key->db is empty, but why would $$key->db be empty now when it's been 1 before this? You didn't do anything else differently between these two runs, did you? Out of curiousity, what's $$key->db represent anyway?

How about moving your die below your if statement. Can't be both 1 and empty. 🙂

[davidjam]

Originally posted by mtmosier
Wow, that makes no sense whatsoever. I mean obviously "inside" will print if $$key->db is empty, but why would $$key->db be empty now when it's been 1 before this? You didn't do anything else differently between these two runs, did you? Out of curiousity, what's $$key->db represent anyway?

How about moving your die below your if statement. Can't be both 1 and empty. 🙂

No, I did nothing different. I always make sure that I reset my session variables and start fresh. All I did was add the die() function.

$$key->db explained (using example): $key = "username", therefore, $$key is the object "username". The property "db" is created when the object "username" is first created (via the constructor). Essentially the constructor "finds" the number I have associated with that element -- username -- and assigns it to ->db. For this example, the number 1 is a default, as I had not assigned any number (i.e. when there is only one table referenced on a given page). The number then references an array from the parent script that says what database table this belongs to: $tables = array(1 => "user", 2 => "another table", etc).

I put the die() below the if() per your instructions and, of course, it never runs because of the continue in the if() statement.

[mtmosier]

But you get inside printing out with values of course, cause the continue couldn't run without hitting the echos. Please post the full output of that.

[davidjam]

Exactly the same as before:

outside if() (for username): $$key->db is: --
inside if() (for username): $$key->db is: --
outside if() (for email_address_1): $$key->db is: --
inside if() (for email_address_1): $$key->db is: --

One test I am working on is to change the number of the database to, like "2" or something to make sure the "1" isn't just a "true" value and not an actual integer. Seems like an easy change? Nope. I discovered a glitch in my code flow (due to recent improvements), so I have to do a little re-write of a section. :rolleyes:

[mtmosier]

1 does get type casted to true in comparisons against booleans, but even a boolean true prints out as a 1 when echoed, so it shouldn't matter in this code. In this run either $$key->db isn't 1, or there's a typo which I just can't see.

Do a var_export of $$key. Inside the if, before the continue, would be a good place.

[davidjam]

I did the var_export() and found that $key->db didn't exist at all. In place of it was another property $key->new_db (used for new forms): var "new_db" = 1. This is the re-write that I mentioned was necessary (now new and existing data forms are implied based on existance of an "id").

So db didn't exist at all. That got me wondering. So I went to the validation/execution section of my script and at the end of it (after the new insert had been done) there is a header("Location: " . $SERVER['PHP_SELF']); statement, because the page needs to be refreshed as the form is now an existing data form and that is when ->db is established. Here's the scoop (and I have to admit I ran across this problem before):

If you don't put a die() statement after a re-direct then sometimes the script just ignores it and proceeds on without the re-direct.

Thus:

header("Location: " . $SERVER['PHP_SELF']);
die();

Thanks so much mtmossier for your patience and help "unlocking" the mystery! 🙂

[mtmosier]

Yeah, definitely need to stop script execution after a header redirect. But instead of die I'd recommend using exit after the header("Location..."). If nothing else it's more logical, since the script isn't encountering an error condition.

Oh, and the script would always continue after the header redirect if you don't exit or die. The question is whether the additional code being executed will be a harmless waste of cpu cycles or will cause some weird bug (or perhaps seeming bug) like this.

[davidjam]

Exactly! It "seemed" like I had a bug near where I was looking. Of course the place it was showing up was symptomatic of a problem somewhere else.

OK, from now on:

header("Location: redirect.php");
exit();

On the side I just read something about adding the following to an exit():

exit("Line: " . __LINE__);

There were some more like FUNCTION FILE. That looked interesting...

Thanks mtmosier and mrhappiness! Insert smiley of appreciation here --> 🙂