How to resolve : “Undefined variable: crumb” error with openclassifieds

Recently on our website which uses openclassifieds scripts for classifieds, we started getting following errors,

 Undefined variable: crumb 

When we looked at other error logs, we see following errors along with the above primarily visible error in browser,

2018-01-31 10:00:26 — ERROR: ErrorException [ 8 ]: Undefined variable: content ~ APPPATH/common/views/alert_terms.php [ 9 ] in oc/kohana/system/classes/Kohana/Kohana/Exception.php:110
2018-01-31 10:00:26 — ERROR: ErrorException [ 8 ]: Undefined variable: data ~ DOCROOT/themes/reclassifieds3/views/header.php [ 36 ] in oc/kohana/system/classes/Kohana/Kohana/Exception.php:110
2018-01-31 10:00:26 — ERROR: ErrorException [ 8 ]: Undefined variable: crumb ~ APPPATH/common/views/breadcrumbs.php [ 7 ] in oc/kohana/system/classes/Kohana/Kohana/Exception.php:110
2018-01-31 10:00:31 — ERROR: Kohana_Exception [ 0 ]: Required route parameter not passed: category ~ APPPATH/kohana/system/classes/Kohana/Route.php [ 572 ] in oc/kohana/system/classes/Kohana/Kohana/Exception.php:110

When we looked at the code, at oc/common/views/breadcrumbs.php its as below,

<?php defined('SYSPATH') or die('No direct script access.');?>
<? if (count($breadcrumbs) > 0) : ?>
        <ul class="breadcrumb">
        <? foreach ($breadcrumbs as $crumb) : ?>
                <? if ($crumb->get_url() !== NULL) :  ?>
                        <li>
                                <a title="<?=HTML::chars($crumb->get_title())?>" href="<?=$crumb->get_url()?>"><?=$crumb->get_title()?></a>
                        </li>
                <? else : ?>
                        <li class="active"><?=$crumb->get_title()?></li>
                <? endif; ?>
        <?endforeach; ?>
</ul>
<? endif; ?>

So, from code its clear that, the error comes from the php code, like

 <li class="active"><?=$crumb->get_title()?></li> 

which shows its not able to identify crumb veriable, so for try, we removed “=” from before $crumb and the error went, but this is not the correct implementation, so when we further searched into internet, we found that

"<?=$crumb"

is required to have get the variable output. and this =$crumb is nothing but the short form of “echo $crumb” and its further detailed as like below,

short_open_tag boolean
Tells PHP whether the short form (<? ?>) of PHP's open tag should be allowed. If you want to use PHP in combination with XML, you can disable this option in order to use <?xml ?> inline. Otherwise, you can print it with PHP, for example: <?php echo '<?xml version="1.0"?>'; ?>. Also, if disabled, you must use the long form of the PHP open tag (<?php ?>).

Note:
This directive also affected the shorthand <?= before PHP 5.4.0, which is identical to <? echo. Use of this shortcut required short_open_tag to be on. Since PHP 5.4.0, <?= is always available.

Reference : php manual

hence to make sure

 "<?=$crumb"

works well, we need to enable short_open_tag from php.ini so, the final solution is add following line into php.ini

 vim php.ini 

and make sure you have following line,

 short_open_tag = On 

If you are using shared hosting of some servers, the php.ini file will be present in /home/your_user_name/public_html/php.ini