From 683e97766d1d205d009a53348e5727e3d77cf8ea Mon Sep 17 00:00:00 2001
From: Nuno Campos <nuno@langchain.dev>
Date: Thu, 26 Oct 2023 17:45:04 +0100
Subject: [PATCH] Fix json key output parser in partial (streaming) mode
 (#12332)

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---
 libs/langchain/langchain/output_parsers/openai_functions.py | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/libs/langchain/langchain/output_parsers/openai_functions.py b/libs/langchain/langchain/output_parsers/openai_functions.py
index 51c485482d..78b3a989b4 100644
--- a/libs/langchain/langchain/output_parsers/openai_functions.py
+++ b/libs/langchain/langchain/output_parsers/openai_functions.py
@@ -130,7 +130,9 @@ class JsonKeyOutputFunctionsParser(JsonOutputFunctionsParser):
     """The name of the key to return."""
 
     def parse_result(self, result: List[Generation], *, partial: bool = False) -> Any:
-        res = super().parse_result(result)
+        res = super().parse_result(result, partial=partial)
+        if partial and res is None:
+            return None
         return res.get(self.key_name) if partial else res[self.key_name]