Comments: Add filter for comment types excluded from queries by default

src/wp-admin/includes/comment.php

@@ -139,6 +139,8 @@ function get_comment_to_edit( $id ) {
  *
  * @since 2.3.0
  * @since 6.9.0 Exclude the 'note' comment type from the count.
+ * @since 7.1.0 The excluded comment types are derived from the
+ *              {@see 'default_excluded_comment_types'} filter.
  *
  * @global wpdb $wpdb WordPress database abstraction object.
  *
@@ -158,7 +160,21 @@ function get_pending_comments_num( $post_id ) {
 	$post_id_array = array_map( 'intval', $post_id_array );
 	$post_id_in    = "'" . implode( "', '", $post_id_array ) . "'";
 
-	$pending = $wpdb->get_results( "SELECT comment_post_ID, COUNT(comment_ID) as num_comments FROM $wpdb->comments WHERE comment_post_ID IN ( $post_id_in ) AND comment_approved = '0' AND comment_type != 'note' GROUP BY comment_post_ID", ARRAY_A );
+	/** This filter is documented in wp-includes/class-wp-comment-query.php */
+	$excluded_types = apply_filters( 'default_excluded_comment_types', array( 'note' ), null );
+	$excluded_types = array_unique( array_filter( array_map( 'strval', (array) $excluded_types ) ) );
+
+	$type_not_in = '';
+	if ( $excluded_types ) {
+		$type_not_in = $wpdb->prepare(
+			sprintf( ' AND comment_type NOT IN ( %s )', implode( ', ', array_fill( 0, count( $excluded_types ), '%s' ) ) ),
+			$excluded_types
+		);
+	}
+
+	// $post_id_in is built from integers and $type_not_in is prepared above.
+	// phpcs:ignore WordPress.DB.PreparedSQL.InterpolatedNotPrepared
+	$pending = $wpdb->get_results( "SELECT comment_post_ID, COUNT(comment_ID) as num_comments FROM $wpdb->comments WHERE comment_post_ID IN ( $post_id_in ) AND comment_approved = '0'$type_not_in GROUP BY comment_post_ID", ARRAY_A );
 
 	if ( $single ) {
 		if ( empty( $pending ) ) {

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

@@ -537,6 +537,7 @@ public function get_comments() {
 	 *
 	 * @since 4.4.0
 	 * @since 6.9.0 Excludes the 'note' comment type, unless 'all' or the 'note' types are requested.
+	 * @since 7.1.0 The default-excluded comment types are filterable via {@see 'default_excluded_comment_types'}.
 	 *
 	 * @global wpdb $wpdb WordPress database abstraction object.
 	 *
@@ -771,13 +772,45 @@ protected function get_comment_ids() {
 			'NOT IN' => (array) $this->query_vars['type__not_in'],
 		);
 
-		// Exclude the 'note' comment type, unless 'all' types or the 'note' type explicitly are requested.
-		if (
-			! in_array( 'all', $raw_types['IN'], true ) &&
-			! in_array( 'note', $raw_types['IN'], true ) &&
-			! in_array( 'note', $raw_types['NOT IN'], true )
-		) {
-			$raw_types['NOT IN'][] = 'note';
+		/**
+		 * Filters the comment types that are excluded from query results by default.
+		 *
+		 * Comment types in this list are omitted from `WP_Comment_Query` results
+		 * unless the query explicitly requests the 'all' type, or requests the
+		 * specific type via the 'type', 'type__in', or 'type__not_in' query
+		 * variables.
+		 *
+		 * This allows plugins to keep comment types out of standard comment
+		 * listings, counts, or feeds by default, without having to filter every
+		 * query individually. The 'note' comment type, used by the editor, is
+		 * excluded by default. The same set is applied when recalculating a
+		 * post's stored comment count in wp_update_comment_count_now(), so an
+		 * excluded type does not inflate get_comments_number().
+		 *
+		 * This exclusion is a default-visibility convenience, not an access-control
+		 * mechanism: callers can still retrieve excluded types explicitly (for
+		 * example with 'type' => 'all'), so do not rely on this filter to keep
+		 * comment data private. Enforce capability checks wherever the data is
+		 * displayed or exposed (for example over REST).
+		 *
+		 * @since 7.1.0
+		 *
+		 * @param string[]              $excluded_types Comment types excluded from query results by default.
+		 *                                               Default array contains the 'note' type.
+		 * @param WP_Comment_Query|null $query          The WP_Comment_Query instance (passed by reference),
+		 *                                               or null when recalculating a post's comment count.
+		 */
+		$excluded_types = apply_filters_ref_array( 'default_excluded_comment_types', array( array( 'note' ), &$this ) );
+
+		// Exclude the default-excluded comment types, unless 'all' types or that type explicitly are requested.
+		foreach ( array_unique( (array) $excluded_types ) as $excluded_type ) {
+			if (
+				! in_array( 'all', $raw_types['IN'], true ) &&
+				! in_array( $excluded_type, $raw_types['IN'], true ) &&
+				! in_array( $excluded_type, $raw_types['NOT IN'], true )
+			) {
+				$raw_types['NOT IN'][] = $excluded_type;
+			}
 		}
 
 		$comment_types = array();

src/wp-includes/comment.php

@@ -2876,7 +2876,28 @@ function wp_update_comment_count_now( $post_id ) {
 	$new = apply_filters( 'pre_wp_update_comment_count_now', null, $old, $post_id );
 
 	if ( is_null( $new ) ) {
-		$new = (int) $wpdb->get_var( $wpdb->prepare( "SELECT COUNT(*) FROM $wpdb->comments WHERE comment_post_ID = %d AND comment_approved = '1' AND comment_type != 'note'", $post_id ) );
+		/** This filter is documented in wp-includes/class-wp-comment-query.php */
+		$excluded_types = apply_filters( 'default_excluded_comment_types', array( 'note' ), null );
+		$excluded_types = array_unique( array_filter( array_map( 'strval', (array) $excluded_types ) ) );
+
+		if ( $excluded_types ) {
+			$new = (int) $wpdb->get_var(
+				$wpdb->prepare(
+					sprintf(
+						"SELECT COUNT(*) FROM $wpdb->comments WHERE comment_post_ID = %%d AND comment_approved = '1' AND comment_type NOT IN (%s)",
+						implode( ', ', array_fill( 0, count( $excluded_types ), '%s' ) )
+					),
+					array_merge( array( $post_id ), $excluded_types )
+				)
+			);
+		} else {
+			$new = (int) $wpdb->get_var(
+				$wpdb->prepare(
+					"SELECT COUNT(*) FROM $wpdb->comments WHERE comment_post_ID = %d AND comment_approved = '1'",
+					$post_id
+				)
+			);
+		}
 	} else {
 		$new = (int) $new;
 	}

tests/phpunit/tests/admin/includes/comment/GetPendingCommentsNum_Test.php

@@ -0,0 +1,118 @@
+<?php
+
+/**
+ * @group admin
+ * @group comment
+ *
+ * @covers ::get_pending_comments_num
+ */
+class Admin_Includes_Comment_GetPendingCommentsNum_Test extends WP_UnitTestCase {
+
+	/**
+	 * Creates a pending (unapproved) comment of a given type on a post.
+	 *
+	 * @param int    $post_id      Post to attach the comment to.
+	 * @param string $comment_type Comment type slug.
+	 * @return int The new comment ID.
+	 */
+	private function make_pending( $post_id, $comment_type = 'comment' ) {
+		return self::factory()->comment->create(
+			array(
+				'comment_post_ID'  => $post_id,
+				'comment_type'     => $comment_type,
+				'comment_approved' => '0',
+			)
+		);
+	}
+
+	/**
+	 * @ticket 65537
+	 */
+	public function test_counts_only_pending_comments() {
+		$post_id = self::factory()->post->create();
+		$this->make_pending( $post_id );
+		self::factory()->comment->create(
+			array(
+				'comment_post_ID'  => $post_id,
+				'comment_approved' => '1',
+			)
+		);
+
+		$this->assertSame( 1, get_pending_comments_num( $post_id ) );
+	}
+
+	/**
+	 * @ticket 65537
+	 */
+	public function test_excludes_note_type_by_default() {
+		$post_id = self::factory()->post->create();
+		$this->make_pending( $post_id );
+		$this->make_pending( $post_id, 'note' );
+
+		$this->assertSame( 1, get_pending_comments_num( $post_id ) );
+	}
+
+	/**
+	 * A type added to the excluded set must drop out of the pending count.
+	 *
+	 * @ticket 65537
+	 */
+	public function test_excludes_a_filtered_type() {
+		$post_id = self::factory()->post->create();
+		$this->make_pending( $post_id );
+		$this->make_pending( $post_id, 'review' );
+
+		// 'review' is counted by default.
+		$this->assertSame( 2, get_pending_comments_num( $post_id ) );
+
+		$filter = static function ( $types ) {
+			$types[] = 'review';
+			return $types;
+		};
+		add_filter( 'default_excluded_comment_types', $filter );
+		$num = get_pending_comments_num( $post_id );
+		remove_filter( 'default_excluded_comment_types', $filter );
+
+		$this->assertSame( 1, $num );
+	}
+
+	/**
+	 * The exclusion is filter-driven, not a hard-coded 'note' literal.
+	 *
+	 * @ticket 65537
+	 */
+	public function test_emptying_filter_counts_note_type() {
+		$post_id = self::factory()->post->create();
+		$this->make_pending( $post_id, 'note' );
+
+		$this->assertSame( 0, get_pending_comments_num( $post_id ) );
+
+		add_filter( 'default_excluded_comment_types', '__return_empty_array' );
+		$num = get_pending_comments_num( $post_id );
+		remove_filter( 'default_excluded_comment_types', '__return_empty_array' );
+
+		$this->assertSame( 1, $num );
+	}
+
+	/**
+	 * @ticket 65537
+	 */
+	public function test_array_input_returns_counts_keyed_by_post() {
+		$post_a = self::factory()->post->create();
+		$post_b = self::factory()->post->create();
+		$this->make_pending( $post_a );
+		$this->make_pending( $post_a, 'note' );
+		$this->make_pending( $post_b );
+		$this->make_pending( $post_b );
+
+		$counts = get_pending_comments_num( array( $post_a, $post_b ) );
+
+		$this->assertSame(
+			array(
+				$post_a => 1,
+				$post_b => 2,
+			),
+			$counts
+		);
+	}
+}