Filtering get_search_sql for advanced queries

[sc0ttkclark]

Currently in the code for 3.1 (trunk) there are no filters running on the new function get_search_sql which would be useful for plugins to perform more complex MySQL functionality on specific columns.

I suggest adding a filter ;)

At the moment, it appears this function has disappeared from trunk for whatever reason. It's no longer in /wp-includes/classes.php so I'll keep an eye out for where it's being moved to before patching.

Related: #15018, #15250

For search, we already have the 'posts_search' filter. Should figure out what to do with that.

In both cases (comment.php / user.php within /wp-includes/), as long as the array passed to get_search_sql is within $this then it can be useful as it is now there is no information available as to what fields are being searched unless the dev copies that code - making it less future proof. Thoughts?

Initial Patch including the new filters for Users / Comments

Added patch that includes the new filters for Users / Comments - implemented in comment.php and user.php (not within get_search_sql function itself due to the lack of information the function is given like no access to $this)

Updated patch for latest SVN Revision (16692)

Updated patch for new $wild var in user get_search_sql

All the Search SQL's should have consistent filters to allow for other search engines to be droped in amongst other things.

This needs a review to ensure that all required locations are changed.

Refreshing this patch w/ 3.5 trunk

Refreshed the patch on this ticket for 3.5

Related: #21803

Changing to use of apply_filters