wp_handle_(upload|sideload) have a lot of copy-pasted code from each other

[nbachiyski]

A huge part of those two functions is the same. It needs to be refactored, so that they share the code.

[wonderboymusic]

23686.diff​ combines the functions into a helper

[helen]

How many of these changes are whitespace/coding standards only?

[wonderboymusic]

very few - the 2 funcs use almost the exact same code - it just makes a new function that has that code that the 2 use

[DrewAPicture]

less whitespacing, more docs

[DrewAPicture]

23686.2.diff​ removes a lot of the whitespacing (sorry Scott :/) and fixes the affected phpDocs.

[wonderboymusic]

Just did a bunch of testing - 23686.3.diff​ is good to go. There were 3 esoteric places where these functions diverged. To test, load this somewhere:

require_once( ABSPATH . 'wp-admin/includes/file.php' );
require_once( ABSPATH . 'wp-admin/includes/media.php' );
media_sideload_image( 'http://cdn3.pitchfork.com/albums/20890/homepage_large.16aa901a.jpg', {YOUR_POST_ID} );

Turns out, $post_id should be optional all the way down the line. The only function that actually uses it for data is wp_insert_attachment(), which allows 0

[wonderboymusic]

In 29209:

Merge wp_handle_upload() and wp_handle_sideload() by making them each wrap a new function: _wp_handle_upload().

Props DrewAPicture for docs.
Fixes #23686.