Use the post-filter WHERE clause when querying for comment descendants.

The descendant query in `WP_Comment_Query::fill_descendants()` uses the clauses
of the main `get_comment_ids()` query as a basis, discarding the `parent`,
`parent__in`, and `parent__not_in` clauses. As implemented in WP 4.4 [34546],
the WHERE clause was assembled in such a way that any modifications applied
using the `comments_clauses` filter were not inherited by `fill_descendants()`.
This resulted in descendant queries that did not always properly filter
results, and sometimes contained syntax errors.

The current changeset fixes the problem by using the post-filter WHERE clause
as the basis for the `fill_descendants()` query. This change requires a new
approach for eliminating the unneeded parent-related clauses: instead of
eliminating values in an associative array, we must use regular expressions.

Props boonebgorges, firebird75.
Fixes #35192.

git-svn-id: https://develop.svn.wordpress.org/trunk@36277 602fd350-edb4-49c9-b593-d223f7449a82

src/wp-includes/class-wp-comment-query.php

@@ -59,6 +59,17 @@ class WP_Comment_Query {
 		'limits'  => '',
 	);
 
+	/**
+	 * SQL WHERE clause.
+	 *
+	 * Stored after the 'comments_clauses' filter is run on the compiled WHERE sub-clauses.
+	 *
+	 * @since 4.4.2
+	 * @access protected
+	 * @var string
+	 */
+	protected $filtered_where_clause;
+
 	/**
 	 * Date query container
 	 *
@@ -823,6 +834,8 @@ class WP_Comment_Query {
 		$limits = isset( $clauses[ 'limits' ] ) ? $clauses[ 'limits' ] : '';
 		$groupby = isset( $clauses[ 'groupby' ] ) ? $clauses[ 'groupby' ] : '';
 
+		$this->filtered_where_clause = $where;
+
 		if ( $where ) {
 			$where = 'WHERE ' . $where;
 		}
@@ -874,12 +887,27 @@ class WP_Comment_Query {
 			0 => wp_list_pluck( $comments, 'comment_ID' ),
 		);
 
-		$where_clauses = $this->sql_clauses['where'];
+		/*
-		unset(
+		 * The WHERE clause for the descendant query is the same as for the top-level
-			$where_clauses['parent'],
+		 * query, minus the `parent`, `parent__in`, and `parent__not_in` sub-clauses.
-			$where_clauses['parent__in'],
+		 */
-			$where_clauses['parent__not_in']
+		$_where = $this->filtered_where_clause;
-		);
+		$exclude_keys = array( 'parent', 'parent__in', 'parent__not_in' );
+		foreach ( $exclude_keys as $exclude_key ) {
+			if ( isset( $this->sql_clauses['where'][ $exclude_key ] ) ) {
+				$clause = $this->sql_clauses['where'][ $exclude_key ];
+
+				// Strip the clause as well as any adjacent ANDs.
+				$pattern = '|(?:AND)?\s*' . $clause . '\s*(?:AND)?|';
+				$_where_parts = preg_split( $pattern, $_where );
+
+				// Remove empties.
+				$_where_parts = array_filter( array_map( 'trim', $_where_parts ) );
+
+				// Reassemble with an AND.
+				$_where = implode( ' AND ', $_where_parts );
+			}
+		}
 
 		// Fetch an entire level of the descendant tree at a time.
 		$level = 0;
@@ -889,7 +917,7 @@ class WP_Comment_Query {
 				break;
 			}
 
-			$where = 'WHERE ' . implode( ' AND ', $where_clauses ) . ' AND comment_parent IN (' . implode( ',', array_map( 'intval', $parent_ids ) ) . ')';
+			$where = 'WHERE ' . $_where . ' AND comment_parent IN (' . implode( ',', array_map( 'intval', $parent_ids ) ) . ')';
 			$comment_ids = $wpdb->get_col( "{$this->sql_clauses['select']} {$this->sql_clauses['from']} {$where} {$this->sql_clauses['groupby']} ORDER BY comment_date_gmt ASC, comment_ID ASC" );
 
 			$level++;

tests/phpunit/tests/comment/query.php

@@ -2128,6 +2128,97 @@ class Tests_Comment_Query extends WP_UnitTestCase {
 		$this->assertEqualSets( array(), array_values( wp_list_pluck( $q->comments[ $c1 ]->get_child( $c2 )->get_children( $args ), 'comment_ID' ) ) );
 	}
 
+	/**
+	 * @ticket 35192
+	 */
+	public function test_comment_clauses_prepend_callback_should_be_respected_when_filling_descendants() {
+		$top_level_0 = self::factory()->comment->create( array(
+			'comment_post_ID' => $this->post_id,
+			'comment_approved' => '1',
+		) );
+
+		$child1_of_0 = self::factory()->comment->create( array(
+			'comment_post_ID' => $this->post_id,
+			'comment_approved' => '1',
+			'comment_parent' => $top_level_0,
+		) );
+
+		$child2_of_0 = self::factory()->comment->create( array(
+			'comment_post_ID' => $this->post_id,
+			'comment_approved' => '1',
+			'comment_parent' => $top_level_0,
+		) );
+
+		$top_level_comments = self::factory()->comment->create_many( 3, array(
+			'comment_post_ID' => $this->post_id,
+			'comment_approved' => '1',
+		) );
+
+		$this->to_exclude = array( $child2_of_0, $top_level_comments[1] );
+
+		add_filter( 'comments_clauses', array( $this, 'prepend_exclusions' ) );
+		$q = new WP_Comment_Query( array(
+			'post_id' => $this->post_id,
+			'hierarchical' => 'flat',
+		) );
+		remove_filter( 'comments_clauses', array( $this, 'prepend_exclusions' ) );
+
+		unset( $this->to_exclude );
+
+		$this->assertEqualSets( array( $top_level_0, $child1_of_0, $top_level_comments[0], $top_level_comments[2] ), wp_list_pluck( $q->comments, 'comment_ID' ) );
+	}
+
+	public function prepend_exclusions( $clauses ) {
+		global $wpdb;
+		$clauses['where'] = $wpdb->prepare( 'comment_ID != %d AND comment_ID != %d AND ', $this->to_exclude[0], $this->to_exclude[1] ) . $clauses['where'];
+		return $clauses;
+	}
+
+	/**
+	 * @ticket 35192
+	 */
+	public function test_comment_clauses_append_callback_should_be_respected_when_filling_descendants() {
+		$top_level_0 = self::factory()->comment->create( array(
+			'comment_post_ID' => $this->post_id,
+			'comment_approved' => '1',
+		) );
+
+		$child1_of_0 = self::factory()->comment->create( array(
+			'comment_post_ID' => $this->post_id,
+			'comment_approved' => '1',
+			'comment_parent' => $top_level_0,
+		) );
+
+		$child2_of_0 = self::factory()->comment->create( array(
+			'comment_post_ID' => $this->post_id,
+			'comment_approved' => '1',
+			'comment_parent' => $top_level_0,
+		) );
+
+		$top_level_comments = self::factory()->comment->create_many( 3, array(
+			'comment_post_ID' => $this->post_id,
+			'comment_approved' => '1',
+		) );
+
+		$this->to_exclude = array( $child2_of_0, $top_level_comments[1] );
+
+		add_filter( 'comments_clauses', array( $this, 'append_exclusions' ) );
+		$q = new WP_Comment_Query( array(
+			'post_id' => $this->post_id,
+			'hierarchical' => 'flat',
+		) );
+		remove_filter( 'comments_clauses', array( $this, 'append_exclusions' ) );
+
+		unset( $this->to_exclude );
+
+		$this->assertEqualSets( array( $top_level_0, $child1_of_0, $top_level_comments[0], $top_level_comments[2] ), wp_list_pluck( $q->comments, 'comment_ID' ) );
+	}
+
+	public function append_exclusions( $clauses ) {
+		global $wpdb;
+		$clauses['where'] .= $wpdb->prepare( ' AND comment_ID != %d AND comment_ID != %d', $this->to_exclude[0], $this->to_exclude[1] );
+		return $clauses;
+	}
 	/**
 	 * @ticket 27571
 	 */