With PHP 7.2, each is deprecated. The documentation says:
Warning This function has been DEPRECATED as of PHP 7.2.0. Relying on this function is highly discouraged.
I am working on adapting an e-commerce application and converting all while-each loops to the (supposedly) equivalent foreach. I bumped into this weirdest issue that I have no clue or probably not enough experience to figure out myself, and I have been trying to do that for the past several days.
There is this this function, inside a class/object, that looks like this:
function get_content_type() {
$this->content_type = false;
if ( (DOWNLOAD_ENABLED == 'true') && ($this->count_contents() > 0) ) {
// reset($this->contents);
// while (list($products_id, ) = each($this->contents)) {
foreach(array_keys($this->contents) as $products_id) {
if (isset($this->contents[$products_id]['attributes'])) {
// reset($this->contents[$products_id]['attributes']);
// while (list(, $value) = each($this->contents[$products_id]['attributes'])) {
foreach ($this->contents[$products_id]['attributes'] as $value) {
As you can see above, I have already replaced the 2 reset & while loops with an equivalent ("equivalent" to the best of my knowledge) foreach
It mostly worked fine. However, we had a customer with very long list of items in her cart that tried to checkout and complained that she gets error 502 from the server. I tried to reproduce that and found that only her cart fails, it takes over 2 minutes for the checkout page to load. I then started debugging a lot of files, trial and error, until I found out that the issue is with this specific function. Whenever I switch the first foreach loop back to the while loop, she can load the checkout page in less than a second. Switching back to foreach - and again it take minutes, but php times out before it ends execution.
I did do tests of course on the output of that foreach vs the while loop (var_dump $products_id and $this->contents for example) and they all seem identical. I already rewrote the code to make it work smoothly and to stay PHP 7.2 compatible, but I still can't figure out why this happens. I am reaching out to the PHP experts here for help. Hopefully you can shed some light on this mystery and/or offer ways to debug this.
In case it's necessary, here is the full function:
function get_content_type() {
$this->content_type = false;
if ( (DOWNLOAD_ENABLED == 'true') && ($this->count_contents() > 0) ) {
// reset($this->contents);
// while (list($products_id, ) = each($this->contents)) {
foreach(array_keys($this->contents) as $products_id) {
if (isset($this->contents[$products_id]['attributes'])) {
// reset($this->contents[$products_id]['attributes']);
// while (list(, $value) = each($this->contents[$products_id]['attributes'])) {
foreach ($this->contents[$products_id]['attributes'] as $value) {
$virtual_check_query = tep_db_query("select count(*) as total from " . TABLE_PRODUCTS_ATTRIBUTES . " pa, " . TABLE_PRODUCTS_ATTRIBUTES_DOWNLOAD . " pad where pa.products_id = '" . (int)$products_id . "' and pa.options_values_id = '" . (int)$value . "' and pa.products_attributes_id = pad.products_attributes_id");
$virtual_check = tep_db_fetch_array($virtual_check_query);
if ($virtual_check['total'] > 0) {
switch ($this->content_type) {
case 'physical':
$this->content_type = 'mixed';
return $this->content_type;
break;
default:
$this->content_type = 'virtual';
break;
}
} else {
switch ($this->content_type) {
case 'virtual':
$this->content_type = 'mixed';
return $this->content_type;
break;
default:
$this->content_type = 'physical';
break;
}
}
}
} elseif ($this->show_weight() == 0) {
// reset($this->contents);
// while (list($products_id, ) = each($this->contents)) {
foreach (array_keys($this->contents) as $products_id) {
$virtual_check_query = tep_db_query("select products_weight from " . TABLE_PRODUCTS . " where products_id = '" . $products_id . "'");
$virtual_check = tep_db_fetch_array($virtual_check_query);
if ($virtual_check['products_weight'] == 0) {
switch ($this->content_type) {
case 'physical':
$this->content_type = 'mixed';
return $this->content_type;
break;
default:
$this->content_type = 'virtual';
break;
}
} else {
switch ($this->content_type) {
case 'virtual':
$this->content_type = 'mixed';
return $this->content_type;
break;
default:
$this->content_type = 'physical';
break;
}
}
}
} else {
switch ($this->content_type) {
case 'virtual':
$this->content_type = 'mixed';
return $this->content_type;
break;
default:
$this->content_type = 'physical';
break;
}
}
}
} else {
$this->content_type = 'physical';
}
return $this->content_type;
}
Thank you
EDIT: here is the array: https://pastebin.com/VawX3XpW
The issue has been tested and reproduced on all the configurations I have tried:
1) High end windows 10 pc + WAMP (Apache 2.4 + MariaDB 10.2 + PHP 5.6+/7+/7.1+/7.2+)
2) High end CentOS/cPanel server + Litespeed + MariaDB 10.1 + PHP 5.6+
Again, just to emphasize, I am not looking to rewrite the code or emulate each and then rewrite the code. I am simply trying to find a logical explanation or a way to solve/debug this mystery. Maybe someone, somewhere, ever bumped into such an issue and can shed some light on this.
UPDATE 01/Aug/2018
I have been trying to debug this for days, eventually noticed something interesting. I added "echo points" and exit on the first foreach loop and while loop like so:
function get_content_type() {
$this->content_type = false;
if ( (DOWNLOAD_ENABLED == 'true') && ($this->count_contents() > 0) ) {
// reset($this->contents);
// while (list($products_id, ) = each($this->contents)) { echo '1 ';
foreach(array_keys($this->contents) as $products_id) { echo '1 ';
if (isset($this->contents[$products_id]['attributes'])) { echo '2 ';
// reset($this->contents[$products_id]['attributes']);
// while (list(, $value) = each($this->contents[$products_id]['attributes'])) {
foreach ($this->contents[$products_id]['attributes'] as $value) { echo '3 ';
$virtual_check_query = tep_db_query("select count(*) as total from " . TABLE_PRODUCTS_ATTRIBUTES . " pa, " . TABLE_PRODUCTS_ATTRIBUTES_DOWNLOAD . " pad where pa.products_id = '" . (int)$products_id . "' and pa.options_values_id = '" . (int)$value . "' and pa.products_attributes_id = pad.products_attributes_id");
$virtual_check = tep_db_fetch_array($virtual_check_query);
if ($virtual_check['total'] > 0) {
switch ($this->content_type) {
case 'physical':
$this->content_type = 'mixed'; echo '4 ';
return $this->content_type;
break;
default:
$this->content_type = 'virtual'; echo '5 ';
break;
}
} else {
switch ($this->content_type) {
case 'virtual':
$this->content_type = 'mixed'; echo '6 ';
return $this->content_type;
break;
default:
$this->content_type = 'physical'; echo '7 ';
break;
}
}
}
} elseif ($this->show_weight() == 0) {
// reset($this->contents);
// while (list($products_id, ) = each($this->contents)) {
foreach (array_keys($this->contents) as $products_id) {
$virtual_check_query = tep_db_query("select products_weight from " . TABLE_PRODUCTS . " where products_id = '" . $products_id . "'");
$virtual_check = tep_db_fetch_array($virtual_check_query);
if ($virtual_check['products_weight'] == 0) {
switch ($this->content_type) {
case 'physical':
$this->content_type = 'mixed'; echo '8 ';
return $this->content_type;
break;
default:
$this->content_type = 'virtual'; echo '9 ';
break;
}
} else {
switch ($this->content_type) {
case 'virtual':
$this->content_type = 'mixed'; echo '10 ';
return $this->content_type;
break;
default:
$this->content_type = 'physical'; echo '11 ';
break;
}
}
}
} else {
switch ($this->content_type) {
case 'virtual':
$this->content_type = 'mixed'; echo '12 ';
return $this->content_type;
break;
default:
$this->content_type = 'physical'; echo '13 ';
break;
}
}
} exit; //Exiting from the loop to check output
} else {
$this->content_type = 'physical';
}
return $this->content_type;
}
When I was running the loop with while, the output I got was just "1 13" once, meaning the loop is running only once. However, when I changed it to foreach, I got a long list of "1 13 1 13 1 13...", meaning it is looping many times. I have gone to investigate further if there is any difference between breaks of while loops and foreach loops, and I still couldn't find any supporting information. I then rewrote the last break; to be break 2; and tested the foreach again and this time it seems to have been running just once, just like when it was a while loop with a break; (not break 2;) I still don't understand how come this happens and what's the difference between a break inside switch inside a while vs inside a switch inside foreach and would appreciate your responses about this.
Thanks again
from While each is deprecated, Foreach replacement takes a lot more time
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