variables somehow changing across functions...

PortaTela · January 9, 2008

Hi. I have some weird problem which i have not been able to understand for some hours now. I consider myself fairly knowledgeable in php, but this problem must be caused by information i missed somewhere.

I have an array with object values assigned to each of its elements:

<?php
#######################
# fields info
#######################

//field
$field_name = "name";
$form_fields_info[$field_name] -> title = "naam";
$form_fields_info[$field_name] -> input_type = "text";
$form_fields_info[$field_name] -> required = true;
$form_fields_info[$field_name] -> fieldset = "persoonsgegevens";
$form_fields_info[$field_name] -> maxlength = 200;

//field
$field_name = "address";
$form_fields_info[$field_name] -> title = "adres";
$form_fields_info[$field_name] -> input_type = "text";
$form_fields_info[$field_name] -> required = true;
$form_fields_info[$field_name] -> fieldset = "persoonsgegevens";
$form_fields_info[$field_name] -> maxlength = 200;
?>

this array is initiated inside a function. after initiating the array i perform a check on submitted form values through a different function:

<?php
if($_POST['submitted'] == "yes")
{
$submitted_form_fields_info = $form_fields_info;

list($submitted_form_fields_info, $warnings_string) = verify_submitted_info($submitted_form_fields_info, $form_hidden_fields_info, $prefix);

if(!empty($submitted_form_fields_info))
{
	$form_fields_info = $submitted_form_fields_info;
}
}
?>

The problem is that when the verify_submitted_info function has been performed, somehow, even when the returning array $submitted_form_fields_info is empty, $form_fields_info will get the same (new) values which were added to $submitted_form_fields_info in the verify_submitted_info function. I always thought variables are only valid within the function they are used in (except for global variables of course). Yet adding values to elements of a DIFFERENT array in a another function is having its effect on a "lookalike" array in the calling function... Can anyone please help me understand what is causing this behaviour?

beneath you will find teh complete code. Ty in advance.

<?php

if (strpos($_SERVER["SCRIPT_NAME"],basename(__FILE__)) !== false)
{
header("location: " . $_SERVER['host_name'] . "/index.php");
exit;
}

function get_concerts_info()
{
global $db;

$sql =
"
	SELECT *
	FROM `events`
	WHERE	`name` = 'concert'
	ORDER BY `date` ASC, `time` ASC, `city` ASC;
";

$concerts_info = $db -> getAssoc($sql);

return $concerts_info;
}

function book($_max_width)
{
$concerts_info = get_concerts_info();

$prefix = "bk_";

$_measures[1] = $_max_width; //volle breedte hoofddiv
$_measures[2] = 25; //required / inrequired div
$_measures[3] = 20; //line height
$_measures[4] = 165; //title_div width
$_measures[8] = 20; //input spacing
$_measures[7] = $_measures[1] - 20; //row div width
$_measures[5] = $_measures[7] - $_measures[2] - $_measures[4] - 2; //input_div width (-2 for ie)
$_measures[6] = $_measures[5] - $_measures[8]; //input_div width

#######################
# fields info
#######################

//field
$field_name = "name";
$form_fields_info[$field_name] -> title = "naam";
$form_fields_info[$field_name] -> input_type = "text";
$form_fields_info[$field_name] -> required = true;
$form_fields_info[$field_name] -> fieldset = "persoonsgegevens";
$form_fields_info[$field_name] -> maxlength = 200;

//field
$field_name = "address";
$form_fields_info[$field_name] -> title = "adres";
$form_fields_info[$field_name] -> input_type = "text";
$form_fields_info[$field_name] -> required = true;
$form_fields_info[$field_name] -> fieldset = "persoonsgegevens";
$form_fields_info[$field_name] -> maxlength = 200;

//field
$field_name = "postalcode_city";
$form_fields_info[$field_name] -> title = "postcode & woonplaats";
$form_fields_info[$field_name] -> input_type = "text";
$form_fields_info[$field_name] -> required = true;
$form_fields_info[$field_name] -> fieldset = "persoonsgegevens";
$form_fields_info[$field_name] -> maxlength = 200;

//field
$field_name = "country";
$form_fields_info[$field_name] -> title = "land";
$form_fields_info[$field_name] -> input_type = "text";
$form_fields_info[$field_name] -> required = true;
$form_fields_info[$field_name] -> fieldset = "persoonsgegevens";
$form_fields_info[$field_name] -> maxlength = 200;
$form_fields_info[$field_name] -> value = "Nederland";

//field
$field_name = "email";
$form_fields_info[$field_name] -> title = "email";
$form_fields_info[$field_name] -> input_type = "text";
$form_fields_info[$field_name] -> required = true;
$form_fields_info[$field_name] -> fieldset = "contactgegevens";
$form_fields_info[$field_name] -> maxlength = 200;

//field
$field_name = "phone_nr";
$form_fields_info[$field_name] -> title = "telefoonnummer";
$form_fields_info[$field_name] -> input_type = "text";
$form_fields_info[$field_name] -> required = true;
$form_fields_info[$field_name] -> fieldset = "contactgegevens";
$form_fields_info[$field_name] -> maxlength = 200;


//field
$field_name = "nr_bookings";
$form_fields_info[$field_name] -> title = "aantal reserveringen";
$form_fields_info[$field_name] -> input_type = "text";
$form_fields_info[$field_name] -> required = true;
$form_fields_info[$field_name] -> fieldset = "bestelgegevens";
$form_fields_info[$field_name] -> maxlength = 3;
$form_fields_info[$field_name] -> value = 1;

//field
$field_name = "discount";
$form_fields_info[$field_name] -> title = "korting";
$form_fields_info[$field_name] -> discribtion = "korting geldt alleen voor studenten & genodigden";
$form_fields_info[$field_name] -> input_type = "radio";
$form_fields_info[$field_name] -> required = true;
$form_fields_info[$field_name] -> fieldset = "bestelgegevens";
$form_fields_info[$field_name] -> value[1] = "ja";
$form_fields_info[$field_name] -> value[2] = "nee";
$form_fields_info[$field_name] -> checked = 2;

//field
$field_name = "event";
$form_fields_info[$field_name] -> title = "concert";
$form_fields_info[$field_name] -> input_type = "checkbox";
$form_fields_info[$field_name] -> required = true;
$form_fields_info[$field_name] -> fieldset = "bestelgegevens";

foreach($concerts_info as $concertID => $concert_info)
{
	if(!empty($concert_info -> day_name))
	{
		$concert_title = $concert_info -> day_name;
	}

	if(!empty($concert_info -> date))
	{
		$concert_date = sqlDate2screenDate_2($concert_info -> date);

		if(!empty($concert_title))
		{
			$concert_title .= " ";
		}

		$concert_title .= $concert_date;
	}

	if(!empty($concert_info -> city))
	{
		if(!empty($concert_title))
		{
			$concert_title .= ", ";
		}

		$concert_title .= $concert_info -> city;
	}

	if(!empty($concert_info -> facility_name))
	{
		if(!empty($concert_title))
		{
			$concert_title .= ", ";
		}

		if(!empty($concert_info -> facility_link))
		{
			$concert_title .= "<a href=\"{$concert_info -> facility_link}\" target=\"_blank\">" . $concert_info -> facility_name . "</a>";
		}
		else
		{
			$concert_title .= $concert_info -> facility_name;
		}
	}

	if(!empty($concert_info -> time))
	{
		$concert_time = substr($concert_info -> time, 0, 5);

		if(!empty($concert_title))
		{
			if(empty($concert_info -> facility_name))
			{
				$concert_title .= ", ";
			}
			else
			{
				$concert_title .= " ";
			}
		}

		$concert_title .= $concert_time;
	}

	if(!empty($concert_title))
	{
		$form_fields_info[$field_name] -> value[$concertID] = $concert_title;
	}
}
$form_fields_info[$field_name] -> checked = array();

//field
$field_name = "submit";
$form_fields_info[$field_name] -> value = "verzend";
$form_fields_info[$field_name] -> input_type = "submit";
$form_fields_info[$field_name] -> required = false;
$form_fields_info[$field_name] -> fieldset = "plaats reservering";

//hidden fields

#######################

if($_POST['submitted'] == "yes")
{
	$submitted_form_fields_info = $form_fields_info;

	list($submitted_form_fields_info, $warnings_string) = verify_submitted_info($submitted_form_fields_info, $form_hidden_fields_info, $prefix);

	if(!empty($submitted_form_fields_info))
	{
		$form_fields_info = $submitted_form_fields_info;
	}
}

$fields = create_fields($form_fields_info, $form_hidden_fields_info, $prefix, $_measures);

$parent_div = <<<HERE
<div class="floatLeft" style="width: {$_measures[1]}px; clear: both; margin-top: 5px;">
	<div class="floatLeft warning" style="width: {$_measures[1]}px; clear: both;">
			$warnings_string
	</div>
	<div class="floatLeft" style="width: {$_measures[1]}px; clear: both;">
		<form name="book_form" method="POST">
			$fields
		</form>	
	</div>
</div>
HERE;

return $parent_div;
}

function verify_submitted_info($submitted_form_fields_info, $form_hidden_fields_info, $prefix)
{
$noSucces = false;

foreach($submitted_form_fields_info as $field_name => $field_attributes)
{
	unset($checked_values);

	switch($field_attributes -> input_type)
	{
		case 'text':
			if(empty($_POST[$prefix . $field_name]))
			{
				if($field_attributes -> required)
				{
					$noSucces = true;
					$warnings_string .= "het volgende veld is niet ingevuld: " . $field_attributes -> title . "<br />";
					$submitted_form_fields_info[$field_name] -> classes = "warning";
				}

				$submitted_form_fields_info[$field_name] -> value = "";
			}
			else
			{
				$submitted_form_fields_info[$field_name] -> value = $_POST[$prefix . $field_name];
			}
		break;

		case 'radio':
			if(empty($_POST[$prefix . $field_name]))
			{
				if($field_attributes -> required)
				{
					$noSucces = true;
					$warnings_string .= "het volgende veld is niet ingevuld: " . $field_attributes -> title . "<br />";
					$submitted_form_fields_info[$field_name] -> classes = "warning";
				}

				$submitted_form_fields_info[$field_name] -> checked = "";
			}
			else
			{
				$submitted_form_fields_info[$field_name] -> checked = $_POST[$prefix . $field_name];
			}
		break;

		case 'checkbox':
			foreach($field_attributes -> value as $value => $option_title)
			{
				if($_POST[$prefix . $field_name . "_" . $value] == "on")
				{
					 $checked_values[] = $value;
				}
			}

			if(empty($checked_values))
			{
				if($field_attributes -> required)
				{
					$noSucces = true;
					$warnings_string .= "het volgende veld is niet ingevuld: " . $field_attributes -> title . "<br />";
					$submitted_form_fields_info[$field_name] -> classes = "warning";
				}

				$submitted_form_fields_info[$field_name] -> checked = array();
			}
			else
			{
				$submitted_form_fields_info[$field_name] -> checked = $checked_values;
			}
		break;
	}
}

if($noSucces)
{
	//return array($submitted_form_fields_info, $warnings_string);
}
else
{
	return NULL;
}

}

function create_fields($form_fields_info, $form_hidden_fields_info, $prefix, $_measures)
{

$required_div = <<<HERE
<div class="floatLeft required" style="width: {$_measures[2]}px; height: {$_measures[3]}px; padding: 0px;" title="verplicht"><!-- --></div>
HERE;

$inrequired_div = <<<HERE
<div class="floatLeft" style="width: {$_measures[2]}px; height: {$_measures[3]}px; padding: 0px;"><!-- --></div>
HERE;

foreach($form_fields_info as $field_name => $field_attributes)
{
	$fieldset_string = "";

	if(empty($last_fieldset))
	{
		$last_fieldset = $field_attributes -> fieldset;
		$fieldset_string = "<fieldset><legend>{$field_attributes -> fieldset}</legend>";
	}
	else
	{
		if(!($last_fieldset == $field_attributes -> fieldset))
		{
			$fieldset_string = "</fieldset><fieldset><legend>{$field_attributes -> fieldset}</legend>";
		}

		$last_fieldset = $field_attributes -> fieldset;
	}

	if($field_attributes -> required)
	{
		$requirency = $required_div;
	}
	else
	{
		$requirency = $inrequired_div;
	}

	unset($input_field);
	unset($ckecked_options);

	switch($field_attributes -> input_type)
	{
		case 'text':
			$input_field = <<<HERE
			<input id="input_id_{$field_name}" type="text" name="{$prefix}{$field_name}" value="{$field_attributes -> value}" maxlength="{$field_attributes -> maxlength}" class="floatRight" style="width: {$_measures[6]}px;">
HERE;
		break;

		case 'radio':

			$ckecked_options[$field_attributes -> checked] = "CHECKED";

			foreach($field_attributes -> value as $value => $option_title)
			{
				$input_field .= <<<HERE
				<label><input type="radio" name="{$prefix}{$field_name}" value="$value" $ckecked_options[$value]>
				$option_title</label><br />
HERE;
			}

			$input_field = <<<HERE
			<div class="floatLeft" style="margin-left: {$_measures[8]}px;">$input_field </div>
HERE;
		break;

		case 'checkbox':
			foreach($field_attributes -> checked as $checked_value)
			{
				$ckecked_options[$checked_value] = "CHECKED";
			}

			foreach($field_attributes -> value as $value => $option_title)
			{
				$input_field .= <<<HERE
				<label><input type="checkbox" name="{$prefix}{$field_name}_{$value}" $ckecked_options[$value]>
				$option_title</label><br />
HERE;
			}

			$input_field = <<<HERE
			<div class="floatLeft" style="margin-left: {$_measures[8]}px;">$input_field </div>
HERE;
		break;

		case 'submit':
			$input_field = <<<HERE
			<input class="floatRight" type="submit" value="{$field_attributes -> value}">
HERE;
		break;
	}

	$fields .= <<<HERE
	$fieldset_string
	<div class="floatLeft" style="width: {$_measures[7]}px; clear: both;">
		$requirency
		<div class="floatLeft {$form_fields_info[$field_name] -> classes}" style="width: {$_measures[4]}px; line-height: {$_measures[3]}px;">
			<label for="input_id_{$field_name}">
				{$field_attributes -> title}<br /><span class="attention_form">{$field_attributes -> discribtion}</span>
			</label>
		</div>
		<div class="floatLeft" style="width: {$_measures[5]}px; line-height: {$_measures[3]}px;">
			$input_field
		</div>
	</div>
HERE;
}

if(!empty($form_hidden_fields_info))
{
	foreach($form_hidden_fields_info as $field_name => $value)
	{
		$fields .= <<<HERE
		<input type="hidden" name="$field_name" value="$value">
HERE;
	}
}

$fields .= <<<HERE
		<input type="hidden" name="submitted" value="yes">
HERE;

$fields .= "</fieldset>";

return $fields;
}

?>

PortaTela · January 10, 2008

Since there was no answer for a day i may assume that none knows the explanation for this phenomenon? Or is my description of the problem so crappy that none bothered to even check it out :/

For now i solved the problem in a not-so-gentle way, so im not hasty for an answer. However, just out of personal interest i still would like to understand how the storage of object variables works ($variable[array_element_key] -> object = value). I have had trouble with it before, also concerning the values being changed across different functions. If my explanation was too crappy i will try to write a simple and short script sometime soon in which i can point out the problem i came across.

any wisdom shared with me on this subject still greatly appreciated.

btherl · January 10, 2008

See this script:

<?php
$a->val = 1;
f($a);

function f($a) {
  $a->val = 2;
}

var_dump($a);
?>

So it just passes an object and alters it inside. Run it under php 4 and you'll find the output is 1, but run it under php 5 and the output is 2. The point is that php 5 passes objects by reference, but php 4 passes them copy-on-write.

Since you seem to be using objects to store data only, you might want to use an array instead of an object. Arrays will still be passed copy-on-write even in php 5.

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variables somehow changing across functions...

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