From e98843404a6dc298fe153eff741ca6104b179bfd Mon Sep 17 00:00:00 2001
From: EvanYao826 <2869018789@qq.com>
Date: Tue, 14 Jul 2026 08:56:18 +0800
Subject: [PATCH] fix: skip missing jinja2 variables instead of raising
 (#38655)

When a Jinja2 variable referenced in prompt_config.jinja2_variables
is not present in the variable pool (e.g. because a conditional
branch was not taken), the LLM node should not fail with
VariableNotFoundError. The Jinja2 template already handles optional
variables with constructs like {% if variable is defined %}.

Instead of calling _get_required_variable (which raises), use
variable_pool.get() directly and skip missing variables.
---
 src/graphon/nodes/llm/node.py | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/src/graphon/nodes/llm/node.py b/src/graphon/nodes/llm/node.py
index 137c010a..b1839abb 100644
--- a/src/graphon/nodes/llm/node.py
+++ b/src/graphon/nodes/llm/node.py
@@ -1129,7 +1129,14 @@ def _fetch_jinja_inputs(self, node_data: LLMNodeData) -> dict[str, str]:
 
         variables: dict[str, str] = {}
         for variable_selector in node_data.prompt_config.jinja2_variables or []:
-            variable = self._get_required_variable(variable_selector)
+            variable = self.graph_runtime_state.variable_pool.get(
+                variable_selector.value_selector,
+            )
+            if variable is None:
+                # Variable not in pool — the Jinja2 template handles this
+                # gracefully with {% if variable is defined %}, so skip it
+                # rather than raising VariableNotFoundError.
+                continue
             variables[variable_selector.variable] = self._stringify_jinja_variable(
                 variable,
             )