Permalinks not redirecting from various types to setting value

[gmisura]

On a fresh install of WordPress4.0, I changed the permalink structure to "Day and Name" (i.e. yyyy/mm/dd/sample-post). If you go to /sample-post/ you are redirected to yyyy/mm/dd/sample-post (expected).

However, if you change the permalink structure to "Post Name" and you request the url: 2014/10/03/hello-world/ you are not redirected to /hello-world/ you get a 404 error.

I'd hope that is not intentional, and that this is a bug that can be fixed.

Looks like this extends to other settings:

Some additional testing shows there's a few more bugs:

permalink	?p=1	/yyyy/mm/dd/hello-world/	/yyyy/mm/hello-world/	/archives/1/	/hello-world/
default	HTTP 200	HTTP 200	HTTP 200	HTTP 200	HTTP 200
Day & Name	HTTP 301	HTTP 200	HTTP 301	HTTP 404*	HTTP 301
Month & Name	HTTP 301	HTTP 301	HTTP 200	HTTP 404*	HTTP 301
Numeric	HTTP 301	HTTP 301	HTTP 301	HTTP 200	HTTP 301
Post name	HTTP 301	HTTP 404*	HTTP 404*	HTTP 404*	HTTP 200

(The first column is the setting in wordpress, the top row is the requested URL).

I would expect HTTP 301 for all of the HTTP 404*'s

I poked around the code (though debugging at midnight with a 6am alarm is not smart) and putting in debugging statements, came to what I believe is a problem in query not recognizing the postname in the URL when it comes after dd. If I add ?name=hello-world, things start to act better (i.e. permalink setting: post Name, /yyyy/mm/dd/hello-world/?name=hello-world returns 301 and I get sent to /hello-world as expected).

My goal is to change a long existing blog from Day & name to Post name. For SEO reasons, /post-name should be canonical and all other links should redirect to it.

[jorbin]

@markjaquith and @dd32 - Could one of you triage this and see how much work it would take to ensure we redirect correctly here?

[dd32]

The root cause here is that is_singular() doesn't trigger a redirect if the query finds a valid permalink for a post.

The patches on #14773 / #12456 should fix this, marking as a duplicate of the latter, as it's the closest thing to it.