langchain[patch]: add deprecation warnings (langchain-ai#26853)

libs/langchain/langchain/chains/combine_documents/map_reduce.py

@@ -4,6 +4,7 @@
 
 from typing import Any, Dict, List, Optional, Tuple, Type
 
+from langchain_core._api import deprecated
 from langchain_core.callbacks import Callbacks
 from langchain_core.documents import Document
 from langchain_core.runnables.config import RunnableConfig
@@ -15,6 +16,15 @@
 from langchain.chains.llm import LLMChain
 
 
+@deprecated(
+    since="0.3.1",
+    removal="1.0",
+    message=(
+        "This class is deprecated. Please see the migration guide here for "
+        "a recommended replacement: "
+        "https://python.langchain.com/docs/versions/migrating_chains/map_reduce_chain/"
+    ),
+)
 class MapReduceDocumentsChain(BaseCombineDocumentsChain):
     """Combining documents by mapping a chain over them, then combining results.
 

libs/langchain/langchain/chains/combine_documents/map_rerank.py

@@ -4,6 +4,7 @@
 
 from typing import Any, Dict, List, Optional, Sequence, Tuple, Type, Union, cast
 
+from langchain_core._api import deprecated
 from langchain_core.callbacks import Callbacks
 from langchain_core.documents import Document
 from langchain_core.runnables.config import RunnableConfig
@@ -16,6 +17,15 @@
 from langchain.output_parsers.regex import RegexParser
 
 
+@deprecated(
+    since="0.3.1",
+    removal="1.0",
+    message=(
+        "This class is deprecated. Please see the migration guide here for "
+        "a recommended replacement: "
+        "https://python.langchain.com/docs/versions/migrating_chains/map_rerank_docs_chain/"  # noqa: E501
+    ),
+)
 class MapRerankDocumentsChain(BaseCombineDocumentsChain):
     """Combining documents by mapping a chain over them, then reranking results.
 

libs/langchain/langchain/chains/combine_documents/reduce.py

@@ -4,6 +4,7 @@
 
 from typing import Any, Callable, List, Optional, Protocol, Tuple
 
+from langchain_core._api import deprecated
 from langchain_core.callbacks import Callbacks
 from langchain_core.documents import Document
 from pydantic import ConfigDict
@@ -121,6 +122,15 @@ async def acollapse_docs(
     return Document(page_content=result, metadata=combined_metadata)
 
 
+@deprecated(
+    since="0.3.1",
+    removal="1.0",
+    message=(
+        "This class is deprecated. Please see the migration guide here for "
+        "a recommended replacement: "
+        "https://python.langchain.com/docs/versions/migrating_chains/map_reduce_chain/"
+    ),
+)
 class ReduceDocumentsChain(BaseCombineDocumentsChain):
     """Combine documents by recursively reducing them.
 

libs/langchain/langchain/chains/combine_documents/refine.py

@@ -4,6 +4,7 @@
 
 from typing import Any, Dict, List, Tuple
 
+from langchain_core._api import deprecated
 from langchain_core.callbacks import Callbacks
 from langchain_core.documents import Document
 from langchain_core.prompts import BasePromptTemplate, format_document
@@ -20,6 +21,15 @@ def _get_default_document_prompt() -> PromptTemplate:
     return PromptTemplate(input_variables=["page_content"], template="{page_content}")
 
 
+@deprecated(
+    since="0.3.1",
+    removal="1.0",
+    message=(
+        "This class is deprecated. Please see the migration guide here for "
+        "a recommended replacement: "
+        "https://python.langchain.com/docs/versions/migrating_chains/refine_docs_chain/"  # noqa: E501
+    ),
+)
 class RefineDocumentsChain(BaseCombineDocumentsChain):
     """Combine documents by doing a first pass and then refining on more documents.