wp_rel_nofollow_callback adds too many rel/nofollow attributes

[Denis-de-Bernardy]

if you insert a link in a comment, like:

<a href="foo" rel="bar nofollow">

wp_rel_nofollow_callback() turns that into:

<a href="foo" rel="bar nofollow" rel="nofollow">

Here's a correct implementation of a strip_nofollow() function:

​http://plugins.trac.wordpress.org/browser/sem-dofollow/trunk/sem-dofollow.php

We'd probably want to do the same in WP, and then reverse it: add rel=nofollow if no rel is present, and add a nofollow to the rel if it's not in there already.

[Denis-de-Bernardy]

Some test data to play with

$text = '
<a href="foo" rel="tag nofollow ext">
<a href="foo" rel="nofollow ext">
<a href="foo" rel="tag ext">
<a href="foo" rel ="tag">
<a href="foo" rel="">
<a href="foo" rel
="">
<a href="foo" rel= "">
<a href="foo">
<
a href="foo">
';

[Denis-de-Bernardy]

see also #3842

[Denis-de-Bernardy]

per IRC discussion, there also is a separate issue. unless I'm mistaking, it's possible to add a link in a comment without nofollow, as such:

<a
href="url">

[dilbert4life]

Replying to Denis-de-Bernardy:

To prevent that, we could have it remove line breaks from the comment text, and then run the wp_rel_nofollow function. However, the original problem is still present in 3.1.1. I'll look into this using 9959.patch as a starting point.

[wonderboymusic]

In 34277:

Comments: in wp_rel_nofollow_callback(), account for the fact that a link might already have a rel attribute. Currently, if a link already has a rel, it will result it duplicate attributes on the element with conflicting values.

Adds unit tests.

Props junsuijin, wonderboymusic.
Fixes #9959.

[SergeyBiryukov]

In 35505:

Add missing @group to Tests_Rel_No_Follow.

See #9959.