Index: src/wp-includes/theme.php
===================================================================
--- src/wp-includes/theme.php	(revision 39474)
+++ src/wp-includes/theme.php	(working copy)
@@ -1786,6 +1786,10 @@
 		$r = wp_update_post( wp_slash( $post_data ), true );
 	} else {
 		$r = wp_insert_post( wp_slash( $post_data ), true );
+		// Trigger creation of a revision. See #30854
+		if ( $r && ! is_wp_error( $r ) ) {
+			wp_save_post_revision( $r );
+		}
 	}
 
 	if ( $r instanceof WP_Error ) {