open-webui: patch imports for langchain v1

pkgs/by-name/op/open-webui/langchain-v1.patch

@@ -0,0 +1,27 @@
+diff --git a/backend/open_webui/retrieval/utils.py b/backend/open_webui/retrieval/utils.py
+index da570330b..6ea16e249 100644
+--- a/backend/open_webui/retrieval/utils.py
++++ b/backend/open_webui/retrieval/utils.py
+@@ -10,7 +10,7 @@ import re
+ 
+ from urllib.parse import quote
+ from huggingface_hub import snapshot_download
+-from langchain.retrievers import ContextualCompressionRetriever, EnsembleRetriever
++from langchain_classic.retrievers import ContextualCompressionRetriever, EnsembleRetriever
+ from langchain_community.retrievers import BM25Retriever
+ from langchain_core.documents import Document
+ 
+diff --git a/backend/open_webui/routers/retrieval.py b/backend/open_webui/routers/retrieval.py
+index f8147372f..363bb4706 100644
+--- a/backend/open_webui/routers/retrieval.py
++++ b/backend/open_webui/routers/retrieval.py
+@@ -28,8 +28,7 @@ from pydantic import BaseModel
+ import tiktoken
+ 
+ 
+-from langchain.text_splitter import RecursiveCharacterTextSplitter, TokenTextSplitter
+-from langchain_text_splitters import MarkdownHeaderTextSplitter
++from langchain_text_splitters import MarkdownHeaderTextSplitter, RecursiveCharacterTextSplitter, TokenTextSplitter
+ from langchain_core.documents import Document
+ 
+ from open_webui.models.files import FileModel, Files

pkgs/by-name/op/open-webui/package.nix

@@ -75,6 +75,8 @@ python3Packages.buildPythonApplication rec {
 
   build-system = with python3Packages; [ hatchling ];
 
+  patches = [ ./langchain-v1.patch ];
+
   # Not force-including the frontend build directory as frontend is managed by the `frontend` derivation above.
   postPatch = ''
     substituteInPlace pyproject.toml \
@@ -128,6 +130,7 @@ python3Packages.buildPythonApplication rec {
       iso-639
       itsdangerous
       langchain
+      langchain-classic
       langchain-community
       langdetect
       ldap3