up: update realpath method logic, add new help method

Author: inhere

src/Traits/FileOperateTrait.php

@@ -26,6 +26,7 @@
 use function preg_match;
 use function stat;
 use function str_contains;
+use function str_ends_with;
 use function stream_get_contents;
 use function stream_set_blocking;
 use function strrchr;
@@ -77,6 +78,20 @@ public static function getSuffix(string $filename, bool $clearPoint = false): st
         return $clearPoint ? trim($suffix, '.') : $suffix;
     }
 
+    /**
+     * @param string $filePath file path
+     * @param string $suffix suffix name, with '.'. eg: .json
+     *
+     * @return string
+     */
+    public static function appendSuffix(string $filePath, string $suffix): string
+    {
+        if (!str_ends_with($filePath, $suffix)) {
+            $filePath .= $suffix;
+        }
+        return $filePath;
+    }
+
     /**
      * 获得文件扩展名、后缀名
      *

src/Traits/FileSystemFuncTrait.php

@@ -24,6 +24,7 @@
 use function explode;
 use function function_exists;
 use function get_resource_type;
+use function getcwd;
 use function implode;
 use function is_dir;
 use function is_resource;
@@ -236,7 +237,7 @@ public static function chown(Traversable|array|string $files, string $user, bool
      */
     public static function expandPath(string $path): string
     {
-        $path = realpath($path);
+        return realpath($path);
     }
 
     /**
@@ -261,6 +262,11 @@ public static function realpath(string $path): string
             $parts[0] = OS::getUserHomeDir();
         }
 
+        // `.` is relative path
+        if ($parts[0] === '.') {
+            $parts[0] = (string)getcwd();
+        }
+
         $absolutes = [];
         foreach ($parts as $part) {
             if ('.' === $part) {