Title: undefined function trailingslashit() when .maintenance present Last modified: November 18, 2022 --- # undefined function trailingslashit() when .maintenance present * [grl570810](https://wordpress.org/support/users/grl570810/) * (@grl570810) * [3 years, 6 months ago](https://wordpress.org/support/topic/undefined-function-trailingslashit-when-maintenance-present/) * Looking for some ideas here. Recently (I believe since the arrival of WP 6.1) if I am doing manual updates on any of the sites on my server, and place a .maintenance file in the site root, instead of getting the nice ‘under maintenance’ message they throw a 500 error like this… * > ``` > PHP Fatal error: Uncaught Error: Call to undefined function trailingslashit() in D:\HTTP\WP_Sites\Recipes\wp-includes\class-wp-textdomain-registry.php:103 > Stack trace: > #0 D:\HTTP\WP_Sites\Recipes\wp-includes\l10n.php(784): WP_Textdomain_Registry->set('default', 'en_AU', 'D:\\HTTP\\WP_Site...') > #1 D:\HTTP\WP_Sites\Recipes\wp-includes\load.php(1401): load_textdomain('default', 'D:\\HTTP\\WP_Site...', 'en_AU') > #2 D:\HTTP\WP_Sites\Recipes\wp-includes\load.php(278): wp_load_translations_early() > #3 D:\HTTP\WP_Sites\Recipes\wp-settings.php(74): wp_maintenance() > #4 D:\HTTP\WP_Sites\Recipes\wp-config.php(98): require_once('D:\\HTTP\\WP_Site...') > #5 D:\HTTP\WP_Sites\Recipes\wp-load.php(50): require_once('D:\\HTTP\\WP_Site...') > #6 D:\HTTP\WP_Sites\Recipes\wp-blog-header.php(13): require_once('D:\\HTTP\\WP_Site...') > #7 D:\HTTP\WP_Sites\Recipes\index.php(17): require('D:\\HTTP\\WP_Site...') > #8 {main} > thrown in D:\HTTP\WP_Sites\Recipes\wp-includes\class-wp-textdomain-registry.php on line 103 > ``` > * I don’t have any issues with the sites in normal running, only when I put into maintenance mode. * **NB my server is a Windows machine running PHP 7.4.19 and MySQL 5.7.21.** I mention this as I believe it’s significant; the issue doesn’t occur if I put a .maintenance file onto one of the odd WP sites that I manage on a third party* nix server. My gut feel is that the way Windows uses \ in its path name rather than / in *nix is probably at the root of the issue. * Relevant bits of wp-config: * > ``` > /** Absolute path to the WordPress directory. */ > if ( ! defined( 'ABSPATH' ) ) { > define( 'ABSPATH', __DIR__ . '/' ); > } > > /** Sets up WordPress vars and included files. */ > require_once ABSPATH . 'wp-settings.php'; > > /** Set the Temp Dir to a writable area within the site (defaults to c:\windows\tmp otherwise) */ > define('WP_TEMP_DIR', ABSPATH . 'wp-content/tmp'); > ``` > * I will leave the site listed above in maintenance mode in case folks wish to view if for themselves (it’s a new site for a vanity project so no issue there). * Help???!!! * TIA, Graham * The page I need help with: _[[log in](https://login.wordpress.org/?redirect_to=https%3A%2F%2Fwordpress.org%2Fsupport%2Ftopic%2Fundefined-function-trailingslashit-when-maintenance-present%2F%3Foutput_format%3Dmd&locale=en_US) to see the link]_ Viewing 6 replies - 1 through 6 (of 6 total) * [Hari Shanker R](https://wordpress.org/support/users/harishanker/) * (@harishanker) * [3 years, 6 months ago](https://wordpress.org/support/topic/undefined-function-trailingslashit-when-maintenance-present/#post-16228389) * Hi [@grl570810](https://wordpress.org/support/users/grl570810/) * That is definitely an odd problem! I did some digging, and found details of the changes that happened in WordPress 6.0.1 to: `\wp-includes\class-wp-textdomain- registry.php`: [https://core.trac.wordpress.org/changeset/54669/](https://core.trac.wordpress.org/changeset/54669/) * To summarize, the update changes how `WP_Textdomain_Registry` stores the default languages path. This change addresses a past issue which caused a performance regression during just-in-time changes in locales. It fixes this by storing the default languages paths in a separate way, while at the same time making `WP_Textdomain_Registry` easier to maintain and adding new tests to catch future regressions. Looking at the changeset, I can see how this makes a reference to the [trailingslashit()](https://developer.wordpress.org/reference/functions/trailingslashit/) function and the [untrailingslashit()](https://developer.wordpress.org/reference/functions/untrailingslashit/) function periodically, which adds and removes trailing slashes. * From your error message, it appears that the maintenance mode is triggered from this line: `#3 D:\HTTP\WP_Sites\Recipes\wp-settings.php(74): wp_maintenance()`. However, it appears that while attempting to load the textdomain, one of the changes made in 6.0.1 (potentially the issue I reported above), seems to be causing troubles with the trailingslashit functions, causing this error. * In other words, what I am suggesting is that this might be a core bug, especially since you observed that this is working fine with *nix servers. As you rightly identified, I suspect that it is the forward slashes that are causing the issue. * I would suggest that you test with WordPress 6.0 if the issue repeats itself, and if it doesn’t, we can confirm that changeset #54669 is causing this regression. If that’s the case, would you be so kind as to report a core bug here? [https://core.trac.wordpress.org/newticket](https://core.trac.wordpress.org/newticket) More on that here: [https://make.wordpress.org/core/handbook/testing/reporting-bugs/](https://make.wordpress.org/core/handbook/testing/reporting-bugs/) * I know that wasn’t a solution, but I do hope that this guides you in the right direction! * Thread Starter [grl570810](https://wordpress.org/support/users/grl570810/) * (@grl570810) * [3 years, 6 months ago](https://wordpress.org/support/topic/undefined-function-trailingslashit-when-maintenance-present/#post-16229435) * Hi [@harishanker](https://wordpress.org/support/users/harishanker/), * Thanks so much for your informative response and for the work you have but in to investigate my issue. I will do as you suggest and test on a WP 6.0 site as soon as I get a bit of bandwidth (most likely this coming weekend); by the sound of things I believe you have probably pinpointed the source of the errant behaviour. If I can confirm that I will be very pleased to report it as a core bug (it will be quite exciting to do so, the first I have ever been involved in!). * Regards, Graham - This reply was modified 3 years, 6 months ago by [grl570810](https://wordpress.org/support/users/grl570810/). * Thread Starter [grl570810](https://wordpress.org/support/users/grl570810/) * (@grl570810) * [3 years, 6 months ago](https://wordpress.org/support/topic/undefined-function-trailingslashit-when-maintenance-present/#post-16239058) * Hi [@harishanker](https://wordpress.org/support/users/harishanker/) , * To update you; I’ve confirmed over the weekend that that issue doesn’t occur on a 6.0.x release site, so I believe you are correct in your diagnosis of the source of the problem. As you suggested I have logged a new ticket 57218 [https://core.trac.wordpress.org/ticket/57218](https://core.trac.wordpress.org/ticket/57218) as a core bug. * Regards, Graham * [Hari Shanker R](https://wordpress.org/support/users/harishanker/) * (@harishanker) * [3 years, 6 months ago](https://wordpress.org/support/topic/undefined-function-trailingslashit-when-maintenance-present/#post-16239434) * Thanks for the update, [@grl570810](https://wordpress.org/support/users/grl570810/) and for doing those tests. Since the issue doesn’t occur in 6.0.x, this definitely looks like a bug to me. * I just took a look at that Trac ticket, and I think you have done a fantastic job over there. Kudos on your first core ticket (and core contribution!). 🙂 * Btw, until the issue stands fixed, if you would like to enable maintenance mode on your site, may I suggest that you use a plugin to achieve this as a stopgap solution? [https://wordpress.org/plugins/search/maintenance+mode/](https://wordpress.org/plugins/search/maintenance+mode/) Since maintenance mode plugins operate in a different way, I feel that using one of those plugins should help you in keeping your site on maintenance mode, and will help you achieve your requirement. * I do hope that this helps you! I also hope that the bug gets fixed in the next release. All the very best! * [Brian North](https://wordpress.org/support/users/aspasa/) * (@aspasa) * [3 years, 6 months ago](https://wordpress.org/support/topic/undefined-function-trailingslashit-when-maintenance-present/#post-16252698) * Very good catch. Thanks. * fwiw I – suddenly (today not yesterday) – got the error locally on WAMP. _Call to undefined function trailingslashit() in C:\wamp64\www\misite\wp-includes\class- wp-textdomain-registry.php on line 103_ * After reading I commented out Line 74 and was up & running in – _less than 60 seconds_!! * Awesome. - This reply was modified 3 years, 6 months ago by [Brian North](https://wordpress.org/support/users/aspasa/). * [Gianluigi](https://wordpress.org/support/users/lastninja/) * (@lastninja) * [3 years, 5 months ago](https://wordpress.org/support/topic/undefined-function-trailingslashit-when-maintenance-present/#post-16292551) * I have the same error but only during the updates of almost any plugin. Maybe it is because the maintenance mode is activated during the process. But I don’t know what to do exactly to fix that. Viewing 6 replies - 1 through 6 (of 6 total) The topic ‘undefined function trailingslashit() when .maintenance present’ is closed to new replies. * In: [Fixing WordPress](https://wordpress.org/support/forum/how-to-and-troubleshooting/) * 6 replies * 4 participants * Last reply from: [Gianluigi](https://wordpress.org/support/users/lastninja/) * Last activity: [3 years, 5 months ago](https://wordpress.org/support/topic/undefined-function-trailingslashit-when-maintenance-present/#post-16292551) * Status: not resolved ## Topics ### Topics with no replies ### Non-support topics ### Resolved topics ### Unresolved topics ### All topics