Fixes #2502: Unclear error message when `$_SERVER['DOCUMENT_ROOT']` is empty

framework/CHANGELOG.md

@@ -46,6 +46,7 @@ Yii Framework 2 Change Log
 - Bug #2303: Fixed the bug that `yii\base\Theme::pathMap` did not support dynamic update with path aliases (qiangxue)
 - Bug #2324: Fixed QueryBuilder bug when building a query with "query" option (mintao)
 - Bug #2399: Fixed the bug that AssetBundle did not handle relative URLs correctly (qiangxue)
+- Bug #2502: Unclear error message when `$_SERVER['DOCUMENT_ROOT']` is empty (samdark)
 - Bug: Fixed `Call to a member function registerAssetFiles() on a non-object` in case of wrong `sourcePath` for an asset bundle (samdark)
 - Bug: Fixed incorrect event name for `yii\jui\Spinner` (samdark)
 - Bug: Json::encode() did not handle objects that implement JsonSerializable interface correctly (cebe)

framework/web/Request.php

@@ -547,7 +547,7 @@ class Request extends \yii\base\Request
 				$this->_scriptUrl = $_SERVER['ORIG_SCRIPT_NAME'];
 			} elseif (($pos = strpos($_SERVER['PHP_SELF'], '/' . $scriptName)) !== false) {
 				$this->_scriptUrl = substr($_SERVER['SCRIPT_NAME'], 0, $pos) . '/' . $scriptName;
-			} elseif (isset($_SERVER['DOCUMENT_ROOT']) && strpos($scriptFile, $_SERVER['DOCUMENT_ROOT']) === 0) {
+			} elseif (!empty($_SERVER['DOCUMENT_ROOT']) && strpos($scriptFile, $_SERVER['DOCUMENT_ROOT']) === 0) {
 				$this->_scriptUrl = str_replace('\\', '/', str_replace($_SERVER['DOCUMENT_ROOT'], '', $scriptFile));
 			} else {
 				throw new InvalidConfigException('Unable to determine the entry script URL.');