From 56525f2ac1a7edae7102208c4afdae8f36251478 Mon Sep 17 00:00:00 2001
From: Harrison Chase <hw.chase.17@gmail.com>
Date: Fri, 29 Mar 2024 17:55:27 -0700
Subject: [PATCH] dont mutate metadata/tags (#19742)

---
 libs/core/langchain_core/prompts/base.py | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/libs/core/langchain_core/prompts/base.py b/libs/core/langchain_core/prompts/base.py
index e1353937dd..a95d7fee68 100644
--- a/libs/core/langchain_core/prompts/base.py
+++ b/libs/core/langchain_core/prompts/base.py
@@ -112,9 +112,9 @@ class BasePromptTemplate(
     ) -> PromptValue:
         config = ensure_config(config)
         if self.metadata:
-            config["metadata"].update(self.metadata)
+            config["metadata"] = {**config["metadata"], **self.metadata}
         if self.tags:
-            config["tags"].extend(self.tags)
+            config["tags"] = config["tags"] + self.tags
         return self._call_with_config(
             self._format_prompt_with_error_handling,
             input,