Post Locking: Replace exclusive lock UI with collaborative editing indicator when RTC is enabled.

When real-time collaboration is enabled, the post list no longer shows exclusive
lock semantics (padlock icon, user avatar, "{user} is currently editing") since
multiple users can collaboratively edit the same post. Instead:

- Shows generic "Currently being edited" text without user-specific info.
- Uses `wp-collaborative-editing` CSS class instead of `wp-locked`, which
  preserves checkbox and row action visibility (no exclusive lock restrictions).
- Changes the "Edit" row action text to "Join" for locked posts.
- Heartbeat responses send generic text with a `collaborative` flag.
- Injects `_wpCollaborationEnabled` into `inline-edit-post` script so the
  heartbeat JS handler applies the correct class on dynamic lock updates.

When RTC is disabled, classic lock behavior is completely unchanged.

Backports WordPress/gutenberg#76322 to core.

Props pkevan.
See #75313.

Author: maxschmeling

src/js/_enqueues/admin/inline-edit-post.js

@@ -613,18 +613,20 @@ $( function() {
 		wp.heartbeat.interval( 10 );
 	}
 }).on( 'heartbeat-tick.wp-check-locked-posts', function( e, data ) {
-	var locked = data['wp-check-locked-posts'] || {};
+	var locked = data['wp-check-locked-posts'] || {},
+		isRtc = window._wpCollaborationEnabled,
+		lockedClass = isRtc ? 'wp-collaborative-editing' : 'wp-locked';
 
 	$('#the-list tr').each( function(i, el) {
 		var key = el.id, row = $(el), lock_data, avatar;
 
 		if ( locked.hasOwnProperty( key ) ) {
-			if ( ! row.hasClass('wp-locked') ) {
+			if ( ! row.hasClass( lockedClass ) ) {
 				lock_data = locked[key];
 				row.find('.column-title .locked-text').text( lock_data.text );
 				row.find('.check-column checkbox').prop('checked', false);
 
-				if ( lock_data.avatar_src ) {
+				if ( ! isRtc && lock_data.avatar_src ) {
 					avatar = $( '<img />', {
 						'class': 'avatar avatar-18 photo',
 						width: 18,
@@ -635,10 +637,10 @@ $( function() {
 					} );
 					row.find('.column-title .locked-avatar').empty().append( avatar );
 				}
-				row.addClass('wp-locked');
+				row.addClass( lockedClass );
 			}
-		} else if ( row.hasClass('wp-locked') ) {
-			row.removeClass( 'wp-locked' ).find( '.locked-info span' ).empty();
+		} else if ( row.hasClass( lockedClass ) ) {
+			row.removeClass( lockedClass ).find( '.locked-info span' ).empty();
 		}
 	});
 }).on( 'heartbeat-send.wp-check-locked-posts', function( e, data ) {

src/wp-admin/css/list-tables.css

@@ -635,6 +635,10 @@ tr.wp-locked .row-actions .trash {
 	display: none;
 }
 
+.wp-collaborative-editing .locked-info {
+	display: block;
+}
+
 #menu-locations-wrap .widefat {
 	width: 60%;
 }

src/wp-admin/includes/class-wp-posts-list-table.php

@@ -1119,10 +1119,15 @@ public function column_title( $post ) {
 			$lock_holder = wp_check_post_lock( $post->ID );
 
 			if ( $lock_holder ) {
-				$lock_holder   = get_userdata( $lock_holder );
-				$locked_avatar = get_avatar( $lock_holder->ID, 18 );
-				/* translators: %s: User's display name. */
-				$locked_text = esc_html( sprintf( __( '%s is currently editing' ), $lock_holder->display_name ) );
+				if ( get_option( 'wp_enable_real_time_collaboration' ) ) {
+					$locked_avatar = '';
+					$locked_text   = esc_html__( 'Currently being edited' );
+				} else {
+					$lock_holder   = get_userdata( $lock_holder );
+					$locked_avatar = get_avatar( $lock_holder->ID, 18 );
+					/* translators: %s: User's display name. */
+					$locked_text = esc_html( sprintf( __( '%s is currently editing' ), $lock_holder->display_name ) );
+				}
 			} else {
 				$locked_avatar = '';
 				$locked_text   = '';
@@ -1427,7 +1432,11 @@ public function single_row( $post, $level = 0 ) {
 		$lock_holder = wp_check_post_lock( $post->ID );
 
 		if ( $lock_holder ) {
-			$classes .= ' wp-locked';
+			if ( get_option( 'wp_enable_real_time_collaboration' ) ) {
+				$classes .= ' wp-collaborative-editing';
+			} else {
+				$classes .= ' wp-locked';
+			}
 		}
 
 		if ( $post->post_parent ) {
@@ -1481,12 +1490,14 @@ protected function handle_row_actions( $item, $column_name, $primary ) {
 		$title            = _draft_or_post_title();
 
 		if ( $can_edit_post && 'trash' !== $post->post_status ) {
+			$is_rtc_locked = get_option( 'wp_enable_real_time_collaboration' ) && wp_check_post_lock( $post->ID );
+
 			$actions['edit'] = sprintf(
 				'<a href="%s" aria-label="%s">%s</a>',
 				get_edit_post_link( $post->ID ),
 				/* translators: %s: Post title. */
-				esc_attr( sprintf( __( 'Edit &#8220;%s&#8221;' ), $title ) ),
-				__( 'Edit' )
+				esc_attr( sprintf( $is_rtc_locked ? __( 'Join editing &#8220;%s&#8221;' ) : __( 'Edit &#8220;%s&#8221;' ), $title ) ),
+				$is_rtc_locked ? __( 'Join' ) : __( 'Edit' )
 			);
 
 			/**

src/wp-admin/includes/misc.php

@@ -1133,7 +1133,8 @@ function _customizer_mobile_viewport_meta( $viewport_meta ) {
  * @return array The Heartbeat response.
  */
 function wp_check_locked_posts( $response, $data, $screen_id ) {
-	$checked = array();
+	$checked        = array();
+	$is_rtc_enabled = (bool) get_option( 'wp_enable_real_time_collaboration' );
 
 	if ( array_key_exists( 'wp-check-locked-posts', $data ) && is_array( $data['wp-check-locked-posts'] ) ) {
 		foreach ( $data['wp-check-locked-posts'] as $key ) {
@@ -1149,15 +1150,22 @@ function wp_check_locked_posts( $response, $data, $screen_id ) {
 				$user = get_userdata( $user_id );
 
 				if ( $user && current_user_can( 'edit_post', $post_id ) ) {
-					$send = array(
-						'name' => $user->display_name,
-						/* translators: %s: User's display name. */
-						'text' => sprintf( __( '%s is currently editing' ), $user->display_name ),
-					);
-
-					if ( get_option( 'show_avatars' ) ) {
-						$send['avatar_src']    = get_avatar_url( $user->ID, array( 'size' => 18 ) );
-						$send['avatar_src_2x'] = get_avatar_url( $user->ID, array( 'size' => 36 ) );
+					if ( $is_rtc_enabled ) {
+						$send = array(
+							'text'          => __( 'Currently being edited' ),
+							'collaborative' => true,
+						);
+					} else {
+						$send = array(
+							'name' => $user->display_name,
+							/* translators: %s: User's display name. */
+							'text' => sprintf( __( '%s is currently editing' ), $user->display_name ),
+						);
+
+						if ( get_option( 'show_avatars' ) ) {
+							$send['avatar_src']    = get_avatar_url( $user->ID, array( 'size' => 18 ) );
+							$send['avatar_src_2x'] = get_avatar_url( $user->ID, array( 'size' => 36 ) );
+						}
 					}
 
 					$checked[ $key ] = $send;

src/wp-includes/collaboration.php

@@ -15,10 +15,9 @@
  */
 function wp_collaboration_inject_setting() {
 	if ( get_option( 'wp_enable_real_time_collaboration' ) ) {
-		wp_add_inline_script(
-			'wp-core-data',
-			'window._wpCollaborationEnabled = true;',
-			'after'
-		);
+		$inline_script = 'window._wpCollaborationEnabled = true;';
+
+		wp_add_inline_script( 'wp-core-data', $inline_script, 'after' );
+		wp_add_inline_script( 'inline-edit-post', $inline_script, 'before' );
 	}
 }