Ticket #53705: avoid-corrupting-concurrent-plugin-upgrades.diff

wp-admin/includes/class-wp-upgrader.php

@@ -311 +311 @@
                 // Clean up contents of upgrade directory beforehand.
                 $upgrade_files = $wp_filesystem->dirlist( $upgrade_folder );
                 if ( ! empty( $upgrade_files ) ) {
+                        $max_cleanup_mtime = time() - DAY_IN_SECONDS;
                         foreach ( $upgrade_files as $file ) {
-                                $wp_filesystem->delete( $upgrade_folder . $file['name'], true );
+                                // Avoid deleting newer files in case they are from concurrent upgrades
+                                if ( $wp_filesystem->mtime( $upgrade_folder . $file['name'] ) < $max_cleanup_mtime ) {
+                                        $wp_filesystem->delete( $upgrade_folder . $file['name'], true );
+                                }
                         }
                 }