fix get_attachment_template() to pass templates array

[willnorris]

get_attachment_template() currently queries for a number of templates based on the mime-type of the attachment. It does so by checking each one individually, and returning as soon as it finds one. It should instead build an array of templates, and pass the entire array to get_query_template().

patch attached.

to be honest, I also think that order it attempts the templates is completely backwards. For an "image/jpeg" attachment, it currently attempts:

• image.php
• jpeg.php
• image_jpeg.php
• attachment.php

the mime-type portion of this list is going from general to specific... shouldn't it instead start by looking for the most specific template, and then back off to the most general? so ...

• image_jpeg.php
• jpeg.php
• image.php
• attachment.php

Now I realize this is not something that can be easily changed since it could potentially break a number of themes. Though I'd be highly surprised if there are that many themes that have different templates for "image.php" and "image_jpeg.php".

perhaps this should be filed as a separate bug so it can be discussed, and not hold up this other patch?

Reversing the order has been mentioned in previous tickets, but I don't think we should bother with thar.

Patch makes sense.

Note that the patch will break older hooks:

• $type[0]_template
• $type[1]_template
• $type[0]_$type[1]_template

We'll only be left with the attachment_template hook. I actually think this makes more sense anyway because of the addition of the $type_template_hierarchy hook added to the get_query_template()function.

I don't think the change would really break compatibility with many (if any) themes/plugins though.

Related #21053.

Also just noticed that with the most specific template, the intended result isn't even used. For instance, a JPEG image would be image_jpeg.php. However, get_query_template uses a regular expression that removes the underscore, thus changing the template it looks for to imagejpeg.php. I suggest that the underscore be changed to a dash, thus matching the WordPress file naming convention and avoiding this problem.

Reorder attachment template hierarchy, change underscore to dash in most specific scenario and pass all templates as an array.

Replying to jfarthing84:

However, get_query_template uses a regular expression that removes the underscore, thus changing the template it looks for to imagejpeg.php.

Related: #21213

#23151 was marked as a duplicate.

Two refreshed patches:

• 15337.patch​ keeps the backwards compatibility, except for the underscore issue in comment:9 (i.e. image_jpeg.php, which previously didn't work, would now do).
• 15337.2.patch​ reverses the order per comment:1 and changes the underscore to a dash.

Both patches also use get_queried_object() instead of the $posts global for consistency with other get_*_template() functions.

15337.3.patch​ is an attempt to keep backwards compatibility for filters, per comment:3.