Canonical Redirect when space(s) are used instead of hyphens when requesting a page

[jamescollins]

Create a page with a slug that contains a hyphen (eg. /page-name/).

If you then visit /page name/ (ie. use a space instead of a hyphen), WordPress currently manages to locate and display the page-name page. This could cause duplicate content issues.

The same issue occurs if multiple spaces are used instead of a hyphen.

As an example, this is the original page: ​http://jamesc.id.au/test-page/

This page is accessible via:

• ​http://jamesc.id.au/test%20page/
• ​http://jamesc.id.au/test%20%20page/
• ​http://jamesc.id.au/test%20%20%20page/
• ​http://jamesc.id.au/test%20%20%20%20page/

and so on.

WordPress should either output a 404 error, or redirect to /page-name/.

Tested using the latest 3.2 trunk (r18110).

[dd32]

Said I'd have a look at this.

I was genuinely surprised that WordPress was locating the correct page to start with, Even more surprised that canonical doesn't already catch it.

[dd32]

Confirmed it on 3.0, 3.1, and trunk already, So punting to a future release.

[dd32]

Canonical redirection for this case is added with the patch on #12456.

As for why this works at all, It can be traced to get_page_by_path(), which replaces %20 with a space before sanitize_title()'ing it, causing the slug to be determined correctly.

[wonderboymusic]

Attached the #12456 patch, which is related - I updated dd32's patch for trunk

[jamescollins]

Replying to dd32:

Confirmed it on 3.0, 3.1, and trunk already

Setting version as per dd32's note.

[jared_smith]

Unit tests

[jared_smith]

I'm not sure the attached patch actually solves the stated problem. I created the 17653-tests.patch​ unit test to ensure that the patch worked, and at least in my environment, it hasn't helped at all.

[boonebgorges]

Removing from trunk as per #30284

[jared_smith]

The tests still apply, but the patch still needs work because it doesn't completely solve the problem it sets out to correct.

[SergeyBiryukov]

Related: #14773

[SergeyBiryukov]

Related: #35437