Fix blank product page for WP e-Commerce and Thesis

Quick Fix  please copy and past the code below, into custom_functions.php

if(function_exists('wpsc_enable_page_filters')){
function temp_remove_filter(){
remove_filter( 'the_content', 'wpsc_products_page', 1 );
}
add_action('wp_loaded','temp_remove_filter',1);

function return_filter(){
add_filter( 'the_content', 'wpsc_products_page', 1 );
}
add_action('thesis_hook_after_header','return_filter',10);
}

after pasting,  do the following 2 steps

(you may comment below while yawning)

PS: if you are not a geek   DO NOT READ FURTHER.  have a nice day

The specifications  are:  Thesis version 1.8  and WP e-Commerce Version 3.8.8.

At this point, we shall go through some basics so as to get a clear understanding on this bug.

WP e-commerce (which is abbreviated WPEC), displays the product page and other pages using the_content filter.

All this action can be found in  ..\wp-content\plugins\wp-e-commerce\wpsc-includes\theme.functions.php on line 1248 or there about.

This  content  filter “add_filter( ‘the_content’, ‘wpsc_products_page’, 1 );” and many others  are added using a function called wpsc_enable_page_filters.

By observing the code you will notice that  the function hooked to the_content filter is  wpsc_products_page.  This is the function responsible for displaying the product page.

on scrutinizing this function you will come across the following logic

$wp_query->current_post = $wp_query->post_count;  (by the way we are still in the same file ” theme.functions.php “, on line 1028 or there about)

i can not claim to know why the above line of code is necessary  (actually i would greatly appreciate getting some insight on that) however i can ascertain that  this line of code  is the basis of our problem.

Analyzing the code from a thesis perspective, we can follow its  execution  up to a point,  where by thesis is building the page header.

The line of code that we are interested in can be found in …\wp-content\themes\thesis_18\lib\classes\head.php on line 12 or there about. On that line  you will find the following function call , $head->meta();. In this function we can jump up to line 146. On this line we find the following line $excerpt = trim(str_replace(‘[...]‘, ”, wp_trim_excerpt(”))); being executed.

in this line we will focus on the wp_trim_excerpt(”) function call. the code for this function is located in ..\wp-includes\formatting.php

In this function we are interested in line 2003. on this line, the execution calls $text = apply_filters(‘the_content’, $text);

At this point (kaboom),  Thesis and WPEC  collied.

By applying  “the_content” filter, essentially the code also executes wpsc_products_page which was hooked using “add_filter( ‘the_content’, ‘wpsc_products_page’, 1 ); ” at the wrong place and time. This is further aggravated by the fact that  ‘wpsc_products_page‘  function runs  $wp_query->current_post = $wp_query->post_count;  Note: this code sets  $wp_query->current_post and gives it a value of 1

As thesis continues to execute we reach a point where the content is rendered.  Lets take it from  thesis_loop::page(); the code is located in ..\wp-content\themes\thesis_18\lib\classes\loop.php.

On Line 27 we have while (have_posts()) { … .

looking at  the execution of  have_posts() on line 746 in  ..\wp-includes\query.php

we find that the code calls $wp_query->have_posts(), which takes as to line 2810 in the same file. On this line we have the following condition check if ( $this->current_post + 1 < $this->post_count ) {.

$this->current_post is already set to 1 by previous code execution.($wp_query->current_post = $wp_query->post_count;),  and  $this->post_count  will always be equal to 1.  So the condition above is similar to  if ( 1 + 1 < 1) {,  therefore the condition fails and the loop is not executed, this  results to  a blank page.

moral of the story:   Quick Fix above simply removes the  ( ‘the_content’, ‘wpsc_products_page’)  filter and then adds it back after the creation of the page header. .

 

Note: if you set the product page as the home page, the code execution follows a different path, therefore the   page is successfully displayed without the quick fix.

 

Cost: as a professional software developer i would have charged around $230 to sort out the above bug