From aa44b8df71a5ffa7c80849d0631d0b1022fd6ebe Mon Sep 17 00:00:00 2001
From: mengyonghao <1533512157@qq.com>
Date: Fri, 19 Dec 2025 14:23:29 +0800
Subject: [PATCH] fix(expression-eval): fix variable extraction issue in Jinja2
 templates

- Resolve the bug where variables inside Jinja2 template expressions were not correctly extracted.
- Ensure expressions containing {{ ... }} are parsed reliably.
---
 api/app/core/workflow/expression_evaluator.py | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/api/app/core/workflow/expression_evaluator.py b/api/app/core/workflow/expression_evaluator.py
index c8875d79..81ab25dc 100644
--- a/api/app/core/workflow/expression_evaluator.py
+++ b/api/app/core/workflow/expression_evaluator.py
@@ -5,6 +5,7 @@
 """
 
 import logging
+import re
 from typing import Any
 
 from simpleeval import simple_eval, NameNotDefined, InvalidExpression
@@ -59,9 +60,10 @@ class ExpressionEvaluator:
         """
         # 移除 Jinja2 模板语法的花括号（如果存在）
         expression = expression.strip()
-        if expression.startswith("{{") and expression.endswith("}}"):
-            expression = expression[2:-2].strip()
-        
+        # "{{system.message}} == {{ user.messge }}" -> "system.message == user.message"
+        pattern = r"\{\{\s*(.*?)\s*\}\}"
+        expression = re.sub(pattern, r"\1", expression).strip()
+
         # 构建命名空间上下文
         context = {
             "var": variables,                    # 用户变量