Canonical redirect for non-existent singular paged content

[smub]

I'm using version 3.4.1

For ex: we have this article on WPBeginner

​http://www.wpbeginner.com/wp-tutorials/how-install-wordpress-cdn-solution-maxcdn/

Anyone can simply add:

​http://www.wpbeginner.com/wp-tutorials/how-install-wordpress-cdn-solution-maxcdn/345/

This will resolve the post with the rel="canonical" for the new page which creates duplicate content.

I tried this with @JJJ at WordCamp columbus. This only works with numbers not letters or characters. It has to do something with post pagination even though the article is not split into pages.

[tommcfarlin]

I can't reproduce this in any theme that's currently located in trunk. The steps I'm following to attempt to reproduce are:

1. Navigate to a single post (i.e., /hello-word/)

2. View source to check the canonical value ( reads <link rel='canonical' href='http://localhost/dev/wordpress/trunk/hello-world/' /> )

3. Append a series of digits after the URL (i.e., /hello-word/1234/)

4. View source to check the canonical URL ( still reads: <link rel='canonical' href='http://localhost/dev/wordpress/trunk/hello-world/' /> )

I've also tried this with Twenty Ten and Twenty Eleven in WordPress 3.4.1 and the canonical URL still renders appropriately regardless of paged value.

Would like to dig into a bit deeper - what theme were you using when seeing this behavior?

[SergeyBiryukov]

Could not reproduce on Twenty Eleven or Twenty Twelve either.

Looking at rel_canonical(), it should always return just the permalink, without additional numbers:
​http://core.trac.wordpress.org/browser/tags/3.4.1/wp-includes/link-template.php#L2290

[ocean90]

I could reproduce it, but forget that I had a SEO plugin active which adds the canonical link and has this bug.

smub, any SEO plugins active?

[smub]

Yikes. Yes, I had WordPress SEO by Yoast plugin active when trying this out. Disabled it, and it seemed to fix the issue. Tried All in One SEO pack, and that one did not have a bug. I guess, I need to start a thread for Yoast.

[sirzooro]

There is another issue here: these URLs are invalid, so in my opinion WP should either return 404 error or perform caconical redirect to URL without page number appended.

[SergeyBiryukov]

Related: #11857 (for archive pages)

[sirzooro]

As I checked, this also happens for paginated comments (e.g. .../post-title/comment-page-4/). Need to fix this too.

[SergeyBiryukov]

Closed #21464 as a duplicate.

[SergeyBiryukov]

This is actually a duplicate of #11694.