|This page in a nutshell: A double redirect is a redirect to another redirect. The MediaWiki software won't follow these redirects. Double redirects are easily fixed by bots, and human editors should devote their efforts elsewhere. However, an editor should not leave behind the double redirects that they created themselves.|
A redirect is a special type of page that automatically causes another page to be displayed in its place. A redirect that points to another redirect is called a double redirect. These pages are unwanted, because Wikipedia's MediaWiki software is currently configured to not follow the second redirect. The MediaWiki feature which will allow it is not mature yet. If someone is redirected to a redirect, the chain stops after the first redirect, like in the example. These situations create unpleasant experiences for the reader and make the navigational structure of the site confusing.
Double redirects are usually created after a page move, when old redirects are left unchanged and pointing towards an old name. Although bots fix most of these within a few days from creation automatically, editors should take care not to manually create double redirects.
How to fix a double redirect
An example double redirect, which has since been corrected by redirecting Morchella esculenta
directly to Morchella
without using Morel
as a half-way point.
- Suppose page title A (Morchella esculenta in the example to the right) redirects to B (Morel), which in turn redirects to C (Morchella).
- Upon following the link to A, you will see, as illustrated, a page containing:
- the page title B;
- a large link to C;
- a small notice saying "Redirected from A"
- Click the "A" in "redirected from A".
- You will see a page containing:
- the page title A;
- a large link to B.
- Click "Edit source" (or "Edit", if no "Edit source" tab is available) and change B to C.
Double redirects and bots
Double redirects are easily and automatically fixed by bots, and most are fixed within a few days of creation. Because of this, human editors would be best off putting their time on other tasks that can't be automated. However, bots will not fix a double redirect if the redirect page is fully protected. The following bots fix double redirects:
This list was compiled from Wikipedia:Bots/Status.
Checking for double redirects
Suppose you want to check whether there are any double redirects to page C. Go to page C and click "What links here" (usually the first link in the "Toolbox" on the lefthand side of the page). Double (or multiple) redirects are those pages which appear in the list with both of these properties:
- Indented at least one level in comparison to the page at the top of the list, AND
- Labelled "(redirect page)".
Note that if you've just moved page C, then there might be only one page which is not indented, (the page at the top of the list), and everything else might be indented at least one level.
Once all double redirects have been fixed, the "What links here" page will have only three types of pages listed:
- Direct links from ordinary pages (not indented, not labelled "(redirect page)").
- Direct links from redirect pages (not indented; labelled "(redirect page)").
- Indirect links from ordinary pages (indented one level, not labelled "(redirect page)").
The first and third categories do not need to be fixed – see Wikipedia:Redirect#Do not "fix" links to redirects that are not broken.
When MediaWiki won't automatically follow a redirect
MediaWiki will not follow a redirect if:
- there are double redirects
- it is a redirect to a Special page
- it is a redirect to a non-existent page
- it is a redirect to an interwiki page