Apply `order` to each passed value for `orderby` in `WP_Query`:

* Since `orderby` in `WP_Query` can accept space-delimited sets, yet only one `order` value: when multiple values are passed (and `DESC` is the order), the default sort order `ASC` is being applied to all values before the last in the set.
* There is a unit test that sporadically fails since 3.6 in `tests/post/revision` due to multiple posts having the same `post_date` from being added so rapidly
* When ordering revisions in `wp_get_post_revisions()`, order by `post_date ID`
* Change the `order` value in `wp_get_post_revisions()` to `ASC`. This will produce SQL like: `ORDER BY $wpdb->posts.post_date ASC, $wpdb->posts.ID ASC`. Previously, this would have produced SQL like: `ORDER BY $wpdb->posts.post_date DESC`, and with the addition of ` ID`: `ORDER BY $wpdb->posts.post_date ASC, $wpdb->posts.ID DESC`. Clearly, wrong. The original SQL produced: `ORDER BY $wpdb->posts.post_date DESC`. As such, return the reversions in reverse order using `array_reverse()`. Not doing so would break "Preview Changes."
* Add unit tests to assert that all of this works.
* All existing unit tests pass with the change to ordering multiple `orderby`s in `WP_Query`.
* In the future, we should support independent `order` for each `orderby`, see #17065.

Props SergeyBiryukov, wonderboymusic.
Fixes #26042.


git-svn-id: https://develop.svn.wordpress.org/trunk@28541 602fd350-edb4-49c9-b593-d223f7449a82

src/wp-includes/query.php

@@ -2668,7 +2668,7 @@ class WP_Query {
 
 				$orderby_array[] = $orderby;
 			}
-			$orderby = implode( ',', $orderby_array );
+			$orderby = implode( ' ' . $q['order'] . ', ', $orderby_array );
 
 			if ( empty( $orderby ) )
 				$orderby = "$wpdb->posts.post_date ".$q['order'];

src/wp-includes/revision.php

@@ -417,7 +417,7 @@ function wp_get_post_revisions( $post_id = 0, $args = null ) {
 	if ( ! $post || empty( $post->ID ) )
 		return array();
 
-	$defaults = array( 'order' => 'DESC', 'orderby' => 'date', 'check_enabled' => true );
+	$defaults = array( 'order' => 'ASC', 'orderby' => 'date ID', 'check_enabled' => true );
 	$args = wp_parse_args( $args, $defaults );
 
 	if ( $args['check_enabled'] && ! wp_revisions_enabled( $post ) )
@@ -428,6 +428,8 @@ function wp_get_post_revisions( $post_id = 0, $args = null ) {
 	if ( ! $revisions = get_children( $args ) )
 		return array();
 
+	$revisions = array_reverse( $revisions ); 
+
 	return $revisions;
 }
 

tests/phpunit/tests/post/revisions.php

@@ -338,4 +338,51 @@ class Tests_Post_Revisions extends WP_UnitTestCase {
 			$this->assertTrue( user_can( $author_user_id, 'read_post', $revision->ID ) );
 		}
 	}
+
+	/**
+	 * @ticket 26042
+	 */
+	function test_wp_get_posts_revisions_sql() {
+		$post = get_default_post_to_edit( 'post', true );
+
+		add_filter( 'query', array( $this, '_filter_query' ) );
+
+		wp_get_post_revisions( $post->ID );
+	}
+
+	function _filter_query( $sql ) {
+		remove_filter( 'query', array( $this, '_filter_query' ) );
+		global $wpdb;
+		$this->assertContains( "ORDER BY $wpdb->posts.post_date ASC, $wpdb->posts.ID ASC", $sql );
+		return $sql;
+	}
+
+	/**
+	 * @ticket 26042
+	 */
+	function test_revision_order() {
+		$ok = 0;
+		$reversed = 0;
+
+		for ( $i = 0; $i < 100; $i++ ) {
+			$post_id = $this->factory->post->create( array( 'post_title' => 'some-post', 'post_type' => 'post', 'post_content' => 'some_content' ) );
+
+			for ( $j = 1; $j < 3; $j++ ) {
+				wp_update_post( array( 'post_content' => 'updated post' . $j , 'ID' => $post_id ) );
+			}
+
+			$revisions = wp_get_post_revisions( $post_id );
+			$first = array_shift( $revisions );
+			$last = array_pop( $revisions );
+
+			if ( $first->ID < $last->ID ) {
+				$reversed++;
+			} else {
+				$ok++;
+			}
+		}
+
+		$this->assertEquals( 100, $ok );
+		$this->assertEquals( 0, $reversed );
+	}
 }