Wrong canonical redirect for paged posts page

[Chouby]

• Setup a site with a static front page and a posts page (let's call it "Posts").
• Take note of the page_id of the posts page. 265 in my case.
• Make sure to use pretty permalinks.
• Create sufficient posts to be able to display the page 2 of the posts page.
• In the address bar, type https://mysite.com/?page_id=265 (the posts page plain permalink) => The site is correctly redirected to https://mysite.com/posts/
• In the address bar, type https://mysite.com/?paged=2&page_id=265 (the paged posts page plain permalink) => The site is wrongly redirected to https://mysite.com/page/2/ and displays an empty content. I would expect the url to be redirected to https://mysite.com/posts/page/2/

[SergeyBiryukov]

Hi there, thanks for the ticket!

This appears to be related to #28081 and #50163, but also seems like a distinct issue, as the page does actually exist.

[afercia]

Testing on latest trunk, I can't seem to be able to reproduce the issue.

• Set the posts page to a page with id=146
• Tried with all the permalink settings other than 'plain'
• The paged 'plain' link still works as expected for me, with both these 2 formats:
  • ​http://localhost:8889/?paged=2&page_id=146
  • ​http://localhost:8889/page/2?page_id=146

@Chouby can you still reproduce the issue on latest trunk, with all plugins deactivated an one of the bundled themes active?

[Chouby]

@afercia Yes I confirm that the bug still exists. I just re-tested with the development version (6.2-alpha-54748) and Twenty Twenty One.

I took the opportunity to debug a bit.
At ​this line, $addl_path is filled with the pagination base and number. Previously, it's an empty string. Then the redirect path is filled ​here.

[afercia]

Thanks @Chouby. I'm afraid I still can't reproduce. Something like ?paged=2&page_id=265 correctly brings me to the second page of the Posts page. Wondering if there's a missing step in the tests instructions or maybe some setting in your environment that is triggering the wrong behavior.