Pages are missing from Parent Page dropdown

[Razorrank]

Describe the bug
This website has 527 published pages. Only 447 pages are being listed in "Parent Page" dropdown.
Following return 100 pages:
wp-json/wp/v2/pages?per_page=100&exclude%5B0%5D=111&parent_exclude%5B0%5D=111&orderby=menu_order&order=asc&context=edit&_locale=user
Following return 100 pages:
wp-json/wp/v2/pages?per_page=100&exclude%5B0%5D=111&parent_exclude%5B0%5D=111&orderby=menu_order&order=asc&context=edit&_locale=user&page=2
Following return 100 pages:
wp-json/wp/v2/pages?per_page=100&exclude%5B0%5D=111&parent_exclude%5B0%5D=111&orderby=menu_order&order=asc&context=edit&_locale=user&page=3
Following return 100 pages:
wp-json/wp/v2/pages?per_page=100&exclude%5B0%5D=111&parent_exclude%5B0%5D=111&orderby=menu_order&order=asc&context=edit&_locale=user&page=4
Following return 100 pages:
wp-json/wp/v2/pages?per_page=100&exclude%5B0%5D=111&parent_exclude%5B0%5D=111&orderby=menu_order&order=asc&context=edit&_locale=user&page=5
Following return 26 pages:
wp-json/wp/v2/pages?per_page=100&exclude%5B0%5D=111&parent_exclude%5B0%5D=111&orderby=menu_order&order=asc&context=edit&_locale=user&page=6
100+100+100+100+100 + 26 = 526 pages are being returned using JSON API. But only 447 pages are being listed in parent page dropdown.

Currently running WordPress 5.3.2.

[Razorrank]

Any updates on this?

[jasmussen]

Hi @Razorrank, it's a little hard to reproduce this.

For testing purposes, can you try installing the Classic Editor plugin and seeing whether you're also seeing 447 pages there, or seeing indeed 526 pages?

[Razorrank]

@jasmussen , I installed the Classic editor and edited the page. It shows 486 items in the parent dropdown list. When I use "Quick Edit" feature it shows 487 items in the parent dropdown.
Thank you

[jasmussen]

Alright so it seems like the problem is not block editor specific. Which leaves two options, it's either intended, or it's an issue with the API. It's very probably the latter — but I wonder if there might be a reason for there being a reduced amount of parent page options. For example maybe you can't make a en existing parent page a child of another parent page? Not sure, but I'll flag this for some more feedback.

[Razorrank]

@jasmussen ,

• Cloned the site to a staging site
• Deactivated all the plugins
• Switched to 2020 Wordpress theme
• Updated the Wordpress to the latest version
• Increased max_execution_time , max_input_time , max_input_vars , memory_limit , post_max_size , upload_max_filesize
• Looked at the error log in the root and /wp-admin/ for any potential relevant error messages but nothing is there!
• Problem persist. The specific page that is not appearing in the parent list is not parent of any other pages.
  If you refer to my first comment, I mentioned that the API collectively returns all the pages(paginated). It is the page-editor/block-editor that is not using that data to populate the parent list. Not sure why you think the issue is from the API!?

Do I need to provide more technical feedback or someone from your team will provide feedback?

Thank you

[jasmussen]

It looks as if you've been exceptionally thorough with feedback here, thank you! Hopefully someone with more in-depth knowledge of the API will be able to look based on the "needs technical feedback" tag I added soon!

[tellthemachines]

Closing as this was fixed in #26397.