Nested Looper Skips Index 0 on Frontend for Penultimate Post - "$post->ID on null" Error in FrontEnd.php Line 201

Support
#1

Hello themeco,

I’ve encountered a critical bug with nested loopers in Cornerstone where the first iteration (index 0) of a child looper is consistently skipped on the frontend for the penultimate post in the parent looper, accompanied by a PHP error.

Environment:

  • Pro Theme/Cornerstone: 6.7.11
  • WordPress: 6.9
  • Caching: FlyingPress

Looper Structure:

  1. Grid (Looper Provider: Custom Post Type “cursussen”)
    └─ Cell (Looper Consumer)
    └─ Div (Looper Provider: {{dc:acf:post_field field=“cursusdata_jaar”}})
    └─ Text (Looper Consumer displaying year)
    └─ Div (Looper Provider: {{dc:looper:field key=“cursus_data”}})
    └─ Text (displaying dates)

The Bug:

  • Works perfectly in Cornerstone builder - all data displays for all posts
  • On frontend: For the penultimate post (second-to-last) in the parent looper:
    • Only index 1 of “cursusdata_jaar” renders
    • Index 0 is completely skipped (not in HTML source)
    • Using {{dc:looper:debug_consumer}} confirms only index 1 exists on frontend
  • All other posts (including the last post) work correctly
  • When I duplicate the problematic post, it works fine, but then the new penultimate post exhibits the same bug

PHP Error in error_log: Got error ‘PHP message: PHP Warning: Attempt to read property “ID” on null in /home/xxx/domains/xxxxxx/public_html/wp-content/themes/pro/cornerstone/includes/classes/Services/FrontEnd.php on line 201’, referer: https://sanopharm.com/cornerstone/edit/38937

Debug Findings:

  • {{dc:looper:count}} returns correct count (2) in both builder and frontend
  • Cache clearing has no effect
  • The issue is in the rendering phase, not data retrieval
  • The $post global appears to be null during nested looper execution for the penultimate item

Any idea why this is happening?

Many thanks in advance!

Dagaloni

#2

Hey @Dagaloni,

Thanks for writing in!

I have inspected your nested Looper. You seem to have forgotten to insert a Looper Consumer for the grandchild loop:
image

The loop structure should be:

Section
  Row - Looper Provider Query Builder
     Column - Looper Consumer
         DIV - Looper Provider Dynamic Content / Looper Consumer
               DIV - Looper Provider Dynamic Content / Looper Consumer
                     Display items

Review your structure and make sure to correct the looper consumer. If needed, use {{dc:looper:field key="name" depth="2"}}. For more details about the “Depth”, check this out:

Thanks.