Emails from WordPress Admin are html encoded

[hexley]

When a comment form is filled out that contains characters that are candidate for html encoding in the display of the comment on the web site, those comments are also html encoded in the display of the notification email send to the author.

Example comment left on my WordPress install:
Ampersand: &
Quote: "
Registered: ®

Resulting email notification:

New comment on your post #168 "Prevent iTunes from creating unnecessary clutter and cruft"
Author : --
E-mail : --
URL    : 
Whois  : --
Comment: 
Ampersand: &
Quote: "
Registered: ®

You can see all comments on this post here:
​http://example.com/prevent-itunes-from-unnecessary-clutter-and-cruft/#comments

Delete it: ​http://example.com/wp-admin/comment.php?action=cdc&c=xxxx
Spam it: ​http://example.com/wp-admin/comment.php?action=cdc&dt=spam&c=xxxx

It appears that only the ampersand has this issue. I am not sure if it also applies to the subject of the email, but can confirm it applies to the body of the email.

The email headers show it was sent as plain text:
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Content-Type: text/plain; charset="UTF-8"

[nacin]

Related #9913.

[nacin]

Confirmed for ampersands.

[solarissmoke]

Decode HTML entities before putting them in plain text notification emails

[solarissmoke]

Also happens with other special chars like < and >. Fix is the same as what was done for #9913.

[johnbillion]

I'd quite like to see this in 3.5. Every time I get a comment notification email with entities in it, I think to myself I need to find this ticket and bump it.

[leemon]

Refreshed patch

[leemon]

I've refreshed the patch

12584.2.patch

[wonderboymusic]

In 35415:

Mail: in wp_notify_postauthor() and wp_notify_moderator(), ensure that special chars aren't HTML-encoded in the email message body.

Props solarissmoke, leemon.
Fixes #12584.

[pavelevap]

Related #32392?