Deprecated: rtrim(): Passing null to parameter #1 ($string) of type string

Okay, it appears, that after going through the onboarding process and actually configuring a backup, the warning goes away.

So might be a deprecation warning related to the onboarding process only.

Hi,

Apologies, our developers will be addressing any deprecated messages. This should not affect your ability to do any backups.

Hi, this happens to me as well on my staging machine where i don’t have a backup location configured. I guess once a backup location is set up everything is fin. Anyway it would be nice to have that fixed, here a detailed stacktrace:

[08-Sep-2023 15:16:46 UTC] PHP Deprecated:  rtrim(): Passing null to parameter #1 ($string) of type string is deprecated in src\app\public\wp-includes\formatting.php on line 2836
[08-Sep-2023 15:16:47 UTC] #0 src\wp-content\plugins\updraftplus\class-updraftplus.php(4711): untrailingslashit(NULL)
#1 src\wp-content\plugins\updraftplus\admin.php(1248): UpdraftPlus->backups_dir_location()
#2 src\wp-content\plugins\updraftplus\admin.php(281): UpdraftPlus_Admin->disk_space_check(36700160)
#3 src\wp-content\plugins\updraftplus\admin.php(580): UpdraftPlus_Admin->setup_all_admin_notices_global(NULL)
#4 src\wp-content\plugins\updraftplus\admin.php(38): UpdraftPlus_Admin->admin_init()
#5 src\wp-content\plugins\updraftplus\admin.php(8): UpdraftPlus_Admin->__construct()
#6 src\wp-content\plugins\updraftplus\updraftplus.php(104): include_once('src...')
#7 src\wp-content\plugins\updraftplus\class-updraftplus.php(481): updraft_try_include_file('admin.php', 'include_once')
#8 src\wp-includes\class-wp-hook.php(310): UpdraftPlus->admin_menu('')
#9 src\wp-includes\class-wp-hook.php(334): WP_Hook->apply_filters(NULL, Array)
#10 src\wp-includes\plugin.php(517): WP_Hook->do_action(Array)
#11 src\wp-admin\admin-ajax.php(45): do_action('admin_init')
#12 {main}

Thanks @paulschiretz – we should get these cleared up soon.

@paulschiretz A detailed stack trace looks useful when reporting issues. Where do you find these, Paul?

@oldrup Hmm it’s a bit of manual work to get those…( A C++ dev would call it printf debugging ?? ) What i did was basically setting WP_DEBUG & WP_DEBUG_LOG to true in the wp-config file and adding

	if(is_null($value) ) {
		$e = new \Exception();
		error_log($e->getTraceAsString());
	}

to the wp-includes/formatting.php on line 2836 after the function header of the function: untrailingslashit <- thats where it happens. Then the output of the stacktrace can be found in your usual debug.txt in the wp-contents folder.

IMPORTANT NOTE: Don’t forget to remove the added code after you got the stacktrace from the log and switch WP_DEBUG & WP_DEBUG_LOG to false again to keep your site production ready!

What the code does in plain english:
As the warning occurs when the variable $value is null my code simply creates an exception and gets the stacktrace of it if the var $value is_null and logs the output via the standard php error_log function.

Hope this clears things up a bit and sorry if it is a bit much ??

I tend to think logging a trace like this is especially useful if the only info you get is a php warning in some of the wp core files as it gives no idea what happened before… i use it a lot!

All the best,
Paul

Thank you so much @paulschiretz, for sharing your insights on debugging WordPress ??

@oldrup Always glad to help! ?? And Congrats on your nice blog full of useful tipps and snippets about wp, really helpful!

Cheers, Paul