What potential issues can arise when using a recursive script to display directory trees in PHP?

One potential issue that can arise when using a recursive script to display directory trees in PHP is infinite recursion, where the script gets stuck in an endless loop. This can happen if the script encounters a symbolic link or a circular reference within the directory structure. To solve this issue, you can keep track of visited directories and prevent revisiting them to break the recursion loop. 

function displayDirectoryTree($dir, $level = 0, $visited = array()) {
    if (in_array($dir, $visited)) {
        return; // Prevent infinite recursion by checking if directory has been visited
    }
    
    $visited[] = $dir; // Mark current directory as visited
    
    $files = scandir($dir);
    
    foreach ($files as $file) {
        if ($file != '.' && $file != '..') {
            echo str_repeat('  ', $level) . $file . PHP_EOL;
            
            if (is_dir($dir . '/' . $file)) {
                displayDirectoryTree($dir . '/' . $file, $level + 1, $visited);
            }
        }
    }
}

// Usage
displayDirectoryTree('/path/to/directory');

Keywords

recursion directory trees PHP file system memory overflow

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