ext/standard Deprecate passing empty string to realpath()

Author: arshidkv12

ext/standard/file.c

@@ -2106,6 +2106,10 @@ PHP_FUNCTION(realpath)
 		Z_PARAM_PATH(filename, filename_len)
 	ZEND_PARSE_PARAMETERS_END();
 
+	if (filename_len == 0) {
+        php_error_docref(NULL, E_DEPRECATED, "Passing empty string to realpath() is deprecated, use getcwd() instead");
+    }
+
 	if (VCWD_REALPATH(filename, resolved_path_buff)) {
 		if (php_check_open_basedir(resolved_path_buff)) {
 			RETURN_FALSE;

ext/standard/tests/file/realpath_empty_string.phpt

@@ -0,0 +1,11 @@
+--TEST--
+realpath() emits deprecation warning when passing empty string
+--FILE--
+<?php
+
+var_dump(realpath(""));
+
+?>
+--EXPECTF--
+Deprecated: realpath(): Passing empty string to realpath() is deprecated, use getcwd() instead in %s on line %d
+string(%d) "%s"