Wikipedia:Double redirects

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An example double-redirect, which has since been corrected by redirecting Morchella esculenta directly to Morchella without using Morel as a half-way point.
Special pages Other versions
Broken redirects ...
Dead-end pages Dead-end pages
Dormant pages Dusty articles
DoubleRedirects Double redirects
Lonely pages Orphaned articles
Long pages ...
New pages New pages feed
Protected pages ...
Short pages ...
Uncategorized Category needed
Uncategorized cats ...
Uncategorized templates Uncategorized templates
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See also: Maintenance Reports

A redirect is a page that automatically causes the text of 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 slow, unpleasant experiences for the reader, waste server resources, 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, an editor should not leave behind the double redirects that he created himself.

How to fix a double redirect[edit]

  • 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:
    • (a) the page title B;
    • (b) a large link to C;
    • (c) a small notice saying "Redirected from A"
  • Click the "A" in "redirected from A".
  • You will see a page containing:
    • (a) the page title A;
    • (b) a large link to B.
  • Click "Edit this page" and change B to C.

Discussion on allowing double redirects[edit]

A question whether double redirects should be allowed in some cases is being discussed on the talk page.

Double redirects and bots[edit]

Double redirects are easily fixed automatically by bots[clarification needed], and most are fixed within a couple days of creation. Because of this, human editors would be best off putting their time on other tasks that can't be automated. As of 31 August 2012, the following bots fix double redirects:

Name Tasks Owner First Approval Status Link(s)
Kwjbot (talk · contribs) Fixing interwiki and double redirects Kwj2772 2008-06-1818 June 2008     -Inactive Rights · BRFAs
MalafayaBot (talk · contribs) Interwiki links, Double redirects, Featured articles Malafaya 2006-09-1010 September 2006     -Inactive Rights · BRFAs
RussBot (talk · contribs) Fixing double redirects and disambiguation links, maintaining WP:DPM, maintaining redirected categories R'n'B 2005-06-022 June 2005     -Active Rights · BRFAs
1 · 2
Xqbot (talk · contribs) Fixing double redirects, other tasks Xqt 2009-12-1313 December 2009     -Active Rights · BRFAs
AvicBot (talk · contribs) Fixing double redirects, other tasks Avicennasis 2011-07-2222 July 2011     -Active Rights · BRFAs

This list was compiled from Wikipedia:Bots/Status.

Lists[edit]

Current list:

alternate link showing 1000 entries: Special:DoubleRedirects (1000)

Old lists:

Checking for double redirects[edit]

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:

  1. Direct links from ordinary pages (not indented, not labelled "(redirect page)").
  2. Direct links from redirect pages (not indented; labelled "(redirect page)").
  3. 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[edit]

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

Old Topbanana method[edit]

The Topbanana method to generate a double redirect report from a Link Analysis Database is to use the following SQL:

SELECT concat( '*[http://en.wikipedia.org/w/wiki.phtml?title=', a1.art_title, '&action=edit ', a1.art_title, '] → ', REPLACE( a2.art_title, '_', ' ') , ' → ', REPLACE( a3.art_title, '_', ' ' ) )
FROM art a1 
JOIN good_links l1 ON a1.art_id = l1.from_id
JOIN art a2 ON l1.to_id = a2.art_id
JOIN good_links l2 ON a2.art_id = l2.from_id
JOIN art a3 ON l2.to_id = a3.art_id
WHERE a1.art_is_redirect = 1
  AND a2.art_is_redirect = 1
  AND a3.art_is_redirect = 0
ORDER BY a1.art_title;

...and then split into subsections by hand.

The Byrial method builds on this code.

See also[edit]