Permalink problem in categories with subcategories

[dezh]

Hello,

It think I may have found a bug. Now here's what I noticed:

I use a clean wordpress install (latest version 3.5.1 without plugins or
themes) with permalinks activated (post name).

In any category without child categories, when I type
"www.mysite.com/?cat=2" in the browser, I automatically get redirected to
the category's permalink: "www.mysite.com/categoryname/"

The behavior is different in categories with child categories: automatic
redirection to permalink is not working. I type "www.mysite.com/?cat=3" and
I do not automatically get redirected to the correct permalink. (I stay on
"www.mysite.com/?cat=3".

There's how to provoke the bug:

• Install the latest wordpress version 3.5.1
• Create a category with sub-categories
• Create another category without sub-categories
• Activate permalinks setting using option "Post name" in Settings > Permalinks
• type ​http://www.mysite.com/?cat=ID - replace ID with either a category without

children or with children

[SergeyBiryukov]

Duplicate of #15256.