bor0 · Oct 22, 2026 · Oct 22, 2026
diff --git a/public_html/wp-content/mu-plugins/wp-cli-commands/backfill-groups-check-ins.php b/public_html/wp-content/mu-plugins/wp-cli-commands/backfill-groups-check-ins.php
@@ -0,0 +1,208 @@
+<?php
+
+/**
+ * A one-time migration, to be deleted once it has been run across the groups network.
+ *
+ * Check-ins used to live in a `wporg_groups_checked_in` comment meta on the RSVP. They are now GatherPress's
+ * own `Check_In` flag, so that the wp-admin RSVPs screen and the event page see the same thing (#2213). This
+ * moves the check-ins recorded before that onto the flag, and removes the old meta.
+ *
+ * The time of each check-in is not carried over: the flag has no time, and nothing ever read it.
+ *
+ * Self-contained on purpose: everything here goes when the file does, apart from the two lines that load it
+ * in `bootstrap.php`.
+ */
+
+namespace WordCamp\Groups\Check_Ins\Backfill;
+
+use GatherPress\Core\Rsvp\Flag\Check_In;
+use WP_CLI, WP_CLI_Command;
+
+use function WP_CLI\Utils\format_items;
+
+defined( 'WPINC' ) || die();
+
+// phpcs:disable Universal.Files.SeparateFunctionsFromOO -- the command and the work it does are one unit here, so that removing the migration is removing one file.
+
+const LEGACY_META_KEY = 'wporg_groups_checked_in';
+
+/**
+ * The RSVPs on one site that still carry the old check-in meta.
+ *
+ * Takes a blog ID and builds the table names itself rather than switching, so that `scan()` can ask this of
+ * every site on the network from a single process.
+ *
+ * @param int|null $blog_id Defaults to the current site.
+ *
+ * @return int[]
+ */
+function get_legacy_check_in_ids( $blog_id = null ) {
+	global $wpdb;
+
+	$prefix = $wpdb->get_blog_prefix( $blog_id );
+
+	// The prefix comes from `get_blog_prefix()`.
+	// phpcs:disable WordPress.DB.PreparedSQL.InterpolatedNotPrepared
+	$comment_ids = $wpdb->get_col( $wpdb->prepare(
+		"SELECT DISTINCT comment_id FROM {$prefix}commentmeta WHERE meta_key = %s ORDER BY comment_id",
+		LEGACY_META_KEY
+	) );
+	// phpcs:enable WordPress.DB.PreparedSQL.InterpolatedNotPrepared
+
+	return array_map( 'absint', $comment_ids );
+}
+
+if ( ! defined( 'WP_CLI' ) || ! WP_CLI ) {
+	return;
+}
+
+/**
+ * WordCamp.org: move Groups check-ins onto GatherPress's check-in flag.
+ */
+class Command extends WP_CLI_Command {
+	/**
+	 * Report which sites have check-ins left to migrate.
+	 *
+	 * Reads each site's `commentmeta` table directly, so it never loads a site or calls `switch_to_blog()`.
+	 * Prints one `<url>` per site with work outstanding, so the output can be piped straight into a loop.
+	 *
+	 * ## OPTIONS
+	 *
+	 * [--verbose]
+	 * : Also report the number of check-ins found on each site, on STDERR.
+	 *
+	 * ## EXAMPLES
+	 *
+	 *     # See which sites need it.
+	 *     wp --url=events.wordpress.org wc-groups-check-ins scan --verbose
+	 *
+	 *     # Migrate only those sites, one process each.
+	 *     wp --url=events.wordpress.org wc-groups-check-ins scan | while read -r site; do
+	 *         wp --url="$site" wc-groups-check-ins migrate
+	 *     done
+	 *
+	 * @param array $args
+	 * @param array $assoc_args
+	 */
+	public function scan( $args, $assoc_args ) {
+		global $wpdb;
+
+		$verbose  = isset( $assoc_args['verbose'] );
+		$sites    = $wpdb->get_results( $wpdb->prepare(
+			"SELECT blog_id, domain, path FROM {$wpdb->blogs} WHERE site_id = %d ORDER BY blog_id",
+			get_current_network_id()
+		) );
+		$found    = 0;
+		$unusable = array();
+
+		// A site whose tables have gone is a broken row, not a reason to stop part-way through a network.
+		$was_suppressing = $wpdb->suppress_errors( true );
+
+		foreach ( $sites as $site ) {
+			$comment_ids = get_legacy_check_in_ids( $site->blog_id );
+
+			// `get_col()` answers an empty array whether the site has nothing or the query failed.
+			if ( $wpdb->last_error ) {
+				$unusable[]       = $site->domain . $site->path;
+				$wpdb->last_error = '';
+
+				continue;
+			}
+
+			if ( ! $comment_ids ) {
+				continue;
+			}
+
+			++$found;
+
+			WP_CLI::line( $site->domain . $site->path );
+
+			if ( $verbose ) {
+				WP_CLI::warning( sprintf( '%s%s (blog %d): %d check-ins.', $site->domain, $site->path, $site->blog_id, count( $comment_ids ) ) );
+			}
+		}
+
+		$wpdb->suppress_errors( $was_suppressing );
+
+		if ( $unusable ) {
+			WP_CLI::warning( sprintf(
+				'%d sites could not be read, and are not in the list above: %s.',
+				count( $unusable ),
+				implode( ', ', array_slice( $unusable, 0, 10 ) ) . ( count( $unusable ) > 10 ? ', ...' : '' )
+			) );
+		}
+
+		if ( $verbose ) {
+			WP_CLI::warning( sprintf( '%d of %d sites have check-ins to migrate.', $found, count( $sites ) ) );
+		}
+	}
+
+	/**
+	 * Migrate the check-ins on one site.
+	 *
+	 * Flags each RSVP as checked in, then removes the old meta. Adding the flag fires
+	 * `gatherpress_rsvp_flag_added`, which keeps the event's record of which dates use check-in in step.
+	 * An RSVP whose flag can't be stored keeps its meta, so a re-run picks it up again.
+	 *
+	 * Safe to re-run: a site with nothing outstanding does one query and stops.
+	 *
+	 * ## OPTIONS
+	 *
+	 * [--dry-run]
+	 * : Report what would change, without changing it.
+	 *
+	 * ## EXAMPLES
+	 *
+	 *     wp --url=events.wordpress.org/group/narnia/ wc-groups-check-ins migrate --dry-run
+	 *     wp --url=events.wordpress.org/group/narnia/ wc-groups-check-ins migrate
+	 *
+	 * @param array $args
+	 * @param array $assoc_args
+	 */
+	public function migrate( $args, $assoc_args ) {
+		if ( ! class_exists( Check_In::class ) ) {
+			WP_CLI::error( sprintf( 'GatherPress 0.36.0 or later is not active on %s.', home_url() ) );
+		}
+
+		$dry_run     = isset( $assoc_args['dry-run'] );
+		$comment_ids = get_legacy_check_in_ids();
+		$results     = array();
+		$unfinished  = 0;
+
+		if ( ! $comment_ids ) {
+			WP_CLI::success( sprintf( 'No check-ins left to migrate on %s.', home_url() ) );
+
+			return;
+		}
+
+		foreach ( $comment_ids as $comment_id ) {
+			$comment  = get_comment( $comment_id );
+			$migrated = $dry_run || ( new Check_In( $comment_id ) )->add();
+
+			if ( $migrated && ! $dry_run ) {
+				delete_comment_meta( $comment_id, LEGACY_META_KEY );
+			} elseif ( ! $migrated ) {
+				++$unfinished;
+			}
+
+			$results[] = array(
+				'RSVP'     => $comment_id,
+				'Event'    => $comment ? (int) $comment->comment_post_ID : '',
+				'Migrated' => $migrated ? 'yes' : 'no',
+			);
+		}
+
+		format_items( 'table', $results, array( 'RSVP', 'Event', 'Migrated' ) );
+
+		if ( $dry_run ) {
+			WP_CLI::success( sprintf( '%d check-ins would be migrated on %s. Run without --dry-run to apply.', count( $results ), home_url() ) );
+		} elseif ( $unfinished ) {
+			// Usually a comment that is no longer an RSVP: `Check_In` refuses anything else.
+			WP_CLI::warning( sprintf( '%d of %d check-ins on %s could not be migrated, and keep the old meta.', $unfinished, count( $results ), home_url() ) );
+		} else {
+			WP_CLI::success( sprintf( '%d check-ins migrated on %s.', count( $results ), home_url() ) );
+		}
+	}
+}
+
+WP_CLI::add_command( 'wc-groups-check-ins', __NAMESPACE__ . '\Command' );
diff --git a/public_html/wp-content/mu-plugins/wp-cli-commands/bootstrap.php b/public_html/wp-content/mu-plugins/wp-cli-commands/bootstrap.php
@@ -16,6 +16,9 @@
 // A one-time migration; remove this line and the file once it has been run across the network.
 require_once __DIR__ . '/backfill-sponsor-agreements.php';
 
+// A one-time migration; remove this line and the file once it has been run across the groups network.
+require_once __DIR__ . '/backfill-groups-check-ins.php';
+
 WP_CLI::add_command( 'wc-dangling', 'WordCamp_CLI_Dangling_Hosts' );
 WP_CLI::add_command( 'wc-misc',     'WordCamp_CLI_Miscellaneous'  );
 WP_CLI::add_command( 'wc-rewrite',  'WordCamp_CLI_Rewrite_Rules'  );

diff --git a/public_html/wp-content/mu-plugins/wporg-groups-frontend/inc/check-in.php b/public_html/wp-content/mu-plugins/wporg-groups-frontend/inc/check-in.php
@@ -10,10 +10,9 @@
  *
  * Storage:
  *
- *   - **Check-ins** live in one `wporg_groups_checked_in` comment meta on the
- *     GatherPress RSVP comment, holding the GMT time of the check-in. Like the
- *     registration answers in `rsvp-questions.php`, keeping it on the comment
- *     means it goes away with the RSVP it belongs to.
+ *   - **Check-ins** are GatherPress's own `Check_In` flag on the RSVP
+ *     comment, so the wp-admin RSVPs screen and this page show and change
+ *     the same thing (#2213). GatherPress drops the flag with the RSVP.
  *   - **Which dates use check-in** lives in one `wporg_groups_check_in_scopes`
  *     post meta on the event: the recurrence ids (or `''` for a plain event)
  *     with at least one check-in. Consumers deciding what "attended" means
@@ -54,6 +53,8 @@
 defined( 'WPINC' ) || die();
 
 use GatherPress\Core\Event\Event;
+use GatherPress\Core\Rsvp\Flag\Check_In as Check_In_Flag;
+use GatherPress\Core\Rsvp\Query;
 use GatherPress\Core\Rsvp\Rsvp;
 use WP_Comment;
 use WP_Error;
@@ -67,9 +68,8 @@
 use function WordCamp\Groups\Frontend\My_Events\get_comment_recurrence_ids;
 use function WordCamp\Groups\Frontend\REST\current_user_can_edit_event;
 
-const CHECKED_IN_META = 'wporg_groups_checked_in';
-const SCOPES_META     = 'wporg_groups_check_in_scopes';
-const WALK_INS_META   = 'wporg_groups_walk_ins_without_account';
+const SCOPES_META   = 'wporg_groups_check_in_scopes';
+const WALK_INS_META = 'wporg_groups_walk_ins_without_account';
 
 /**
  * Upper bound for walk-ins without an account on one date. Far above any
@@ -89,6 +89,27 @@
  */
 function bootstrap(): void {
 	add_action( 'rest_api_init', __NAMESPACE__ . '\register_routes' );
+	add_action( 'gatherpress_rsvp_flag_added', __NAMESPACE__ . '\on_flag_changed', 10, 2 );
+	add_action( 'gatherpress_rsvp_flag_removed', __NAMESPACE__ . '\on_flag_changed', 10, 2 );
+}
+
+/**
+ * Keep the event's record of which dates use check-in in step with every
+ * check-in, including the ones made from the wp-admin RSVPs screen.
+ *
+ * @param int    $comment_id RSVP comment ID.
+ * @param string $flag       Flag slug.
+ */
+function on_flag_changed( int $comment_id, string $flag ): void {
+	$comment = get_comment( $comment_id );
+
+	if ( Check_In_Flag::SLUG !== $flag || ! $comment instanceof WP_Comment ) {
+		return;
+	}
+
+	$scope = get_comment_recurrence_ids( array( $comment_id ) )[ $comment_id ] ?? '';
+
+	sync_scope( (int) $comment->comment_post_ID, $scope );
 }
 
 /**
@@ -212,31 +233,38 @@ function is_open( Event $event ): bool {
  * @param int $comment_id RSVP comment ID.
  */
 function is_checked_in( int $comment_id ): bool {
-	return '' !== (string) get_comment_meta( $comment_id, CHECKED_IN_META, true );
+	return ( new Check_In_Flag( $comment_id ) )->has();
 }
 
 /**
- * Check an RSVP in, or undo it, and keep the event's record of which dates
- * use check-in in step.
+ * Load the check-ins of many RSVPs in one query, ahead of calling
+ * `is_checked_in()` on each.
+ *
+ * @param int[] $comment_ids RSVP comment IDs.
+ */
+function prime_check_ins( array $comment_ids ): void {
+	$comment_ids = array_filter( array_map( 'intval', $comment_ids ) );
+
+	if ( $comment_ids ) {
+		update_object_term_cache( $comment_ids, 'comment' );
+	}
+}
+
+/**
+ * Check an RSVP in, or undo it. `on_flag_changed()` keeps the event's record
+ * of which dates use check-in in step.
  *
  * @param WP_Comment $comment    RSVP comment.
  * @param bool       $checked_in Whether they came.
  */
 function set_checked_in( WP_Comment $comment, bool $checked_in ): void {
-	$comment_id = (int) $comment->comment_ID;
+	$flag = new Check_In_Flag( (int) $comment->comment_ID );
 
 	if ( $checked_in ) {
-		// Keep the original time when someone is checked in twice.
-		if ( ! is_checked_in( $comment_id ) ) {
-			update_comment_meta( $comment_id, CHECKED_IN_META, current_time( 'mysql', true ) );
-		}
+		$flag->add();
 	} else {
-		delete_comment_meta( $comment_id, CHECKED_IN_META );
+		$flag->remove();
 	}
-
-	$scope = get_comment_recurrence_ids( array( $comment_id ) )[ $comment_id ] ?? '';
-
-	sync_scope( (int) $comment->comment_post_ID, $scope );
 }
 
 /**
@@ -249,17 +277,28 @@ function set_checked_in( WP_Comment $comment, bool $checked_in ): void {
  * @param string $scope    Recurrence ID, or `''` for a plain event.
  */
 function sync_scope( int $event_id, string $scope ): void {
-	$checked_in_ids = get_comments(
-		array(
-			'post_id'  => $event_id,
-			'type'     => Rsvp::COMMENT_TYPE,
-			'status'   => 'approve',
-			'meta_key' => CHECKED_IN_META, // phpcs:ignore WordPress.DB.SlowDBQuery.slow_db_query_meta_key -- One event's RSVPs.
-			'fields'   => 'ids',
+	/*
+	 * Filtered here rather than with a `tax_query`: `WP_Comment_Query` keys
+	 * its cache on its own query vars only, so a `tax_query` would share a
+	 * cache entry with the same query without it, and GatherPress's list of
+	 * the event's RSVPs would come back holding only the checked-in ones.
+	 */
+	$rsvp_ids = array_map(
+		'intval',
+		Query::get_instance()->get_rsvps(
+			array(
+				'post_id' => $event_id,
+				'status'  => 'approve',
+				'fields'  => 'ids',
+			)
 		)
 	);
 
-	$recurrence_ids = get_comment_recurrence_ids( array_map( 'intval', $checked_in_ids ) );
+	prime_check_ins( $rsvp_ids );
+
+	$checked_in_ids = array_values( array_filter( $rsvp_ids, __NAMESPACE__ . '\is_checked_in' ) );
+
+	$recurrence_ids = get_comment_recurrence_ids( $checked_in_ids );
 	$has_check_ins  = false;
 
 	foreach ( $checked_in_ids as $comment_id ) {
@@ -464,10 +503,7 @@ function build_list( Event $event, int $event_id ): array {
 		$responses['waiting_list']['records'] ?? array()
 	);
 
-	$comment_ids = array_filter( array_map( 'intval', wp_list_pluck( $records, 'commentId' ) ) );
-	if ( $comment_ids ) {
-		update_meta_cache( 'comment', $comment_ids );
-	}
+	prime_check_ins( wp_list_pluck( $records, 'commentId' ) );
 
 	$user_ids = array_filter( array_map( 'intval', wp_list_pluck( $records, 'userId' ) ) );
 	if ( $user_ids ) {

diff --git a/public_html/wp-content/mu-plugins/wporg-groups-frontend/inc/export.php b/public_html/wp-content/mu-plugins/wporg-groups-frontend/inc/export.php
@@ -885,6 +885,7 @@ function get_event_rsvps( array $event_ids ) {
 
 	$comment_ids = array_map( 'intval', wp_list_pluck( $comments, 'comment_ID' ) );
 	update_meta_cache( 'comment', $comment_ids );
+	Check_In\prime_check_ins( $comment_ids );
 
 	$status_terms = wp_get_object_terms(
 		$comment_ids,

diff --git a/public_html/wp-content/mu-plugins/wporg-groups-frontend/inc/my-events.php b/public_html/wp-content/mu-plugins/wporg-groups-frontend/inc/my-events.php
@@ -124,7 +124,7 @@ function filter_to_attended( array $candidates ): array {
 		return array();
 	}
 
-	update_meta_cache( 'comment', array_column( $candidates, 'comment_id' ) );
+	Check_In\prime_check_ins( array_column( $candidates, 'comment_id' ) );
 
 	return array_values(
 		array_filter(