CMSMadeSimple upgrade to Smarty Templating - unexpected attribute - upgrade

Question

I'm new to CMSMS and taking an older installation through a painful upgrade path to get it to the current version. One of the major changes involves using Smarty 3 for it's templating engine. This change has broken a couple of the existing templates.
The related CMSMS module is called "Product and Inventory Manager" which looks like it's part of "Calguys Module Extensions"
Here's the error message I'm getting:
Syntax Error in template "module_db_tpl:ProductsWithLocation;summary_default" on line 26 "<h2 style="float:left;margin-right:10px;color:"#fff">{$products_path_names.$key parent=$tmp|ltrim:'-1'}</h2>" unexpected "parent" attribute
Here's the entire template that's throwing it:
{if !isset($items)}
{cgerror}<h2>Sorry! There is No material matched the query</h2>{/cgerror}
<p>Please try browsing our "full catalog" here. </p>
{else}
{if empty($products_path_names)}
{assign var='products_pagelimit' value=$actionparams.pagelimit|default:'25'}
{assign var='products_parent' value=$actionparams.hierarchyid|default:$actionparams.parent}
{assign var='products_hier_info' value=$ProductsWithLocation->GetHierarchyInfo($products_parent)}
{assign var='products_path_ids' value='.'|explode:$products_hier_info.hierarchy}
{assign var='products_path_names' value=' | '|explode:$products_hier_info.long_name}
{if !empty($products_parent) }<div style="overflow:hidden">
<h2 style="float:left;margin-right:10px">Browsing </h2>
{foreach from=$products_path_ids key='key' item='tmp' }
{if !$smarty.foreach.default.last}
{module_action_link module='ProductsWithLocation' action='hierarchy' text=$products_path_names.$key page=$page_alias parent=$tmp|ltrim:'0' pagelimit=$products_pagelimit}
{else}
<h2 style="float:left;margin-right:10px;color:"#fff">{$products_path_names.$key parent=$tmp|ltrim:'-1'}</h2>
{/if}
{/foreach}<h2 style="float:left"> Colors...</h2></div>
{/if}
{/if}
<div id="status-bar"
{if isset($pagecount) && $pagecount gt 1}
<span class="page-text">{$curpage} {$oftext} {$pagecount} {$pagetext} </span>
<ul class="paging">
<li>{$firstlink}</li><li>{$prevlink}</li> <li>{$nextlink}</li><li>{$lastlink}</li></ul>
{/if}
Switch Thumb
{if $products_parent !=13 }
<a class="a-z" href="{$products_path_names.$key}_Index.htm">{$products_path_names.$key}</a>
{else}
{/if}
</div>
<ul class="gallery">
{foreach from=$items item=entry}
{*
the summary template has access to custom fields via the $entry->fields hash
and to categories via the $entry->categories array of objects. Also
attribute information is available via $entry->attributes.
you should use the get_template_vars and the print_r modifier to see
what is available
*}
{if $products_parent == 13 }
<li>
<dl>
<dt><a class="tip_trigger more-stone-info" href="{$entry->detail_url}">{$entry->product_name}<span class="tip">More information about <strong style="color:#9BD8EB">{$entry->product_name}</strong></span></a></dt>
{* accessing all of the fields in a list *}
{if isset($entry->fields)}
{foreach from=$entry->fields key='name' item='field'}
{if isset($field->value)}
{if $field->type == 'checkbox' or $field->type == 'image' && isset($field->thumbnail)}
{else}
{/if}
{if $field->type == 'image' && isset($field->thumbnail)}
<span class="tip">More information about <strong style="color:#9BD8EB">{$entry->product_name}</strong></span><img src="{$entry->file_location}/{$field->thumbnail}" alt="{$field->value}"/>
{/if}
{/if}
{/foreach}
{/if}
{assign var='hinfo' value=$ProductsWithLocation->GetHierarchyInfo($entry->hierarchy_id)}
<dd><em>Stone Type: </em>Cambria Quartz</dd>
<dd><em>Collection: </em>{module_action_link module=ProductsWithLocation action=default hierarchyid=$entry->hierarchy_id text=$hinfo.name}</dd>
</dl>
</li>
{else}
<li>
<dl>
<dt><a class="tip_trigger more-stone-info" href="{$entry->detail_url}">{$entry->product_name}<span class="tip">More information about <strong style="color:#9BD8EB">{$entry->product_name}</strong></span></a></dt>
{* accessing all of the fields in a list *}
{if isset($entry->fields)}
{foreach from=$entry->fields key='name' item='field'}
{if isset($field->value) && $field->name != 'GalleryFolder'}
{if $field->type == 'checkbox' or $field->type == 'image' && isset($field->thumbnail)}
{else}
<dd><em>
{$name}
</em>
{if is_array($field->value)}
{if !empty($field->value) }
{foreach from=$field->value item='val'}
{if $field->type == 'image' && isset($field->thumbnail)}
{else}
{module_action_link module=$mod->GetName() action=default fieldid=$field->id fieldval=$val text=$val} {/if}
{/foreach}
{/if}
{else}
{if $field->type == 'image' && isset($field->thumbnail)}
{else}
{module_action_link module=$mod->GetName() action=default fieldid=$field->id fieldval=$field->value text=$field->value} {/if}
{/if}
</dd>
{/if}
{if $field->type == 'image' && isset($field->thumbnail)}
<span class="tip">More information about <strong style="color:#9BD8EB">{$entry->product_name}</strong></span><img src="{$entry->file_location}/{$field->thumbnail}" alt="{$field->value}"/>
{/if}
{/if}
{/foreach}
{/if}
{assign var='hinfo' value=$ProductsWithLocation->GetHierarchyInfo($entry->hierarchy_id)}
<dd><em>Stone Type: </em>{module_action_link module=ProductsWithLocation action=default hierarchyid=$entry->hierarchy_id text=$hinfo.name}</dd>
</dl>
</li>
{/if}
{/foreach}
</ul>{/if}
Here's the relevant snip of that template where the error occurs:
{$products_path_names.$key parent=$tmp|ltrim:'-1'}</h2>
From what I understand we're calling a custom function with a name based on products we have in our database. We're sending it an attribute "parent" which it's not expecting. If I remove that attribute the error goes away but the output gets weird.
Short of a magic bullet I think any clues where to look for this function being defined would help me. I'm also baffled by the use of what appears to be ltrim("-1") so any explanation of that would also be nice. Maybe I can replace this line with a longer if block to correct the function call?
Edit - Here's some sample values for the variables:
$products_path_names.$key holds string 'Granite'
$tmp holds string 00017
Thanks!

Answer 1

I more or less solved it. I got rid of the parent attribute entirely and fixed the weird output by changing this line:
{if !$smarty.foreach.default.last}
to
{if $smarty.foreach.default.last != ''}
It was not counting an empty string as false.
Seems to work now.