From e7a947800e9cbcdb1ad0214b9b5f753eba8eecab Mon Sep 17 00:00:00 2001
From: NathanFreeman <1056159381@qq.com>
Date: Mon, 13 Jul 2026 21:15:52 +0800
Subject: [PATCH] support empty/isset with undefined var

---
 src/CompilerBase.php            |  9 ++++++++-
 tests/std/core/empty_isset.phpt | 16 ++++++++++++++++
 2 files changed, 24 insertions(+), 1 deletion(-)
 create mode 100644 tests/std/core/empty_isset.phpt

diff --git a/src/CompilerBase.php b/src/CompilerBase.php
index 2d8f90dd..c0bd4720 100644
--- a/src/CompilerBase.php
+++ b/src/CompilerBase.php
@@ -3228,8 +3228,15 @@ class CompilerBase implements PropertyAccessContext
 
     protected function parseChainedExpr(NodeAbstract $node, string $op, bool $getValue = false): string
     {
+        $name = $this->parseIdentifier($node);
+
+        // 如果empty/isset中的变量不存在，直接返回true/false
+        if (($op == self::OP_EMPTY || $op == self::OP_ISSET) && $this->isVarExpr($node) && !$this->hasVar($name)) {
+            return $op == self::OP_EMPTY ? 'true' : 'false';
+        }
+
         // TypePHP 编译器不允许操作未定义的变量，PHP 的 isset($var) 可能 $var 未定义
-        $this->checkVarMustExist($node, $this->parseIdentifier($node));
+        $this->checkVarMustExist($node, $name);
         $fn = $this->getChainedFunc($op);
         $expr = $node;
         if ($this->isVarExpr($expr)) {
diff --git a/tests/std/core/empty_isset.phpt b/tests/std/core/empty_isset.phpt
new file mode 100644
index 00000000..f795fdcb
--- /dev/null
+++ b/tests/std/core/empty_isset.phpt
@@ -0,0 +1,16 @@
+--TEST--
+empty() / isset() undefined var
+--FILE--
+<?php
+function main() {
+    var_dump(empty($do));
+    var_dump(isset($do));
+    var_dump(!empty($do));
+    var_dump(!isset($do));
+}
+?>
+--EXPECT--
+bool(true)
+bool(false)
+bool(false)
+bool(true)