Function wp_normalize_path() is causing a deprecated error when $path is null.

[garymarkfuller]

The function wp_normalize_path() is causing the error below on my test environment:

PHP Deprecated: str_replace(): Passing null to parameter #3 ($subject) of type array|string is deprecated in /.../wp-includes/functions.php on line 2182

Locally I altered the function to resolve the error as per the code below:

function wp_normalize_path( $path ) {
	$wrapper = '';
	if(!empty($path)) {
		if ( wp_is_stream( $path ) ) {
			list( $wrapper, $path ) = explode( '://', $path, 2 );

			$wrapper .= '://';
		}

		// Standardize all paths to use '/'.
		$path = str_replace( '\\', '/', $path );

		// Replace multiple slashes down to a singular, allowing for network shares having two slashes.
		$path = preg_replace( '|(?<=.)/+|', '/', $path );

		// Windows paths should uppercase the drive letter.
		if ( ':' === substr( $path, 1, 1 ) ) {
			$path = ucfirst( $path );
		}
	}
	return $wrapper . $path;
}

[jrf]

@garymarkfuller Thanks for reporting this. This issue will need a backtrace to figure out where the error is coming from.

The ​wp_normalize_path() function is documented as only accepting a string and the error you are reporting means something somewhere is passing null to wp_normalize_path(). This needs to be fixed at the source of the problem, not in the wp_normalize_path() function.

[sabernhardt]

#57580 (and #57581) had earlier reports about the deprecated warnings for wp_normalize_path() and wp_is_stream().

The four causes identified on #57580 were all plugins that had added null in the add_submenu_page() function. Those four plugins have been updated for newer PHP, but a ​directory search still finds many plugins doing it wrong. The problem could also be somewhere else.

If you identify the issue in a plugin, please report it to the plugin's author.