core[major]: Upgrade langchain-core to pydantic 2

libs/core/Makefile

@@ -39,7 +39,6 @@ lint_tests: PYTHON_FILES=tests
 lint_tests: MYPY_CACHE=.mypy_cache_test
 
 lint lint_diff lint_package lint_tests:
-	./scripts/check_pydantic.sh .
 	./scripts/lint_imports.sh
 	[ "$(PYTHON_FILES)" = "" ] || poetry run ruff check $(PYTHON_FILES)
 	[ "$(PYTHON_FILES)" = "" ] || poetry run ruff format $(PYTHON_FILES) --diff

libs/core/langchain_core/beta/runnables/context.py

@@ -18,6 +18,8 @@
     Union,
 )
 
+from pydantic import ConfigDict
+
 from langchain_core._api.beta_decorator import beta
 from langchain_core.runnables.base import (
     Runnable,
@@ -229,8 +231,9 @@ class ContextSet(RunnableSerializable):
 
     keys: Mapping[str, Optional[Runnable]]
 
-    class Config:
-        arbitrary_types_allowed = True
+    model_config = ConfigDict(
+        arbitrary_types_allowed=True,
+    )
 
     def __init__(
         self,

libs/core/langchain_core/chat_history.py

@@ -20,13 +20,14 @@
 from abc import ABC, abstractmethod
 from typing import List, Sequence, Union
 
+from pydantic import BaseModel, Field
+
 from langchain_core.messages import (
     AIMessage,
     BaseMessage,
     HumanMessage,
     get_buffer_string,
 )
-from langchain_core.pydantic_v1 import BaseModel, Field
 
 
 class BaseChatMessageHistory(ABC):

libs/core/langchain_core/documents/base.py

@@ -4,10 +4,12 @@
 import mimetypes
 from io import BufferedReader, BytesIO
 from pathlib import PurePath
-from typing import Any, Generator, List, Literal, Mapping, Optional, Union, cast
+from typing import Any, Dict, Generator, List, Literal, Optional, Union, cast
+
+from pydantic import ConfigDict, Field, model_validator
 
 from langchain_core.load.serializable import Serializable
-from langchain_core.pydantic_v1 import Field, root_validator
+from langchain_core.utils.pydantic import v1_repr
 
 PathLike = Union[str, PurePath]
 
@@ -110,9 +112,10 @@ class Blob(BaseMedia):
     path: Optional[PathLike] = None
     """Location where the original content was found."""
 
-    class Config:
-        arbitrary_types_allowed = True
-        frozen = True
+    model_config = ConfigDict(
+        arbitrary_types_allowed=True,
+        frozen=True,
+    )
 
     @property
     def source(self) -> Optional[str]:
@@ -127,8 +130,9 @@ def source(self) -> Optional[str]:
             return cast(Optional[str], self.metadata["source"])
         return str(self.path) if self.path else None
 
-    @root_validator(pre=True)
-    def check_blob_is_valid(cls, values: Mapping[str, Any]) -> Mapping[str, Any]:
+    @model_validator(mode="before")
+    @classmethod
+    def check_blob_is_valid(cls, values: Dict[str, Any]) -> Any:
         """Verify that either data or path is provided."""
         if "data" not in values and "path" not in values:
             raise ValueError("Either data or path must be provided")
@@ -293,3 +297,7 @@ def __str__(self) -> str:
             return f"page_content='{self.page_content}' metadata={self.metadata}"
         else:
             return f"page_content='{self.page_content}'"
+
+    def __repr__(self) -> str:
+        # TODO(0.3): Remove this override after confirming unit tests!
+        return v1_repr(self)

libs/core/langchain_core/documents/compressor.py

@@ -3,9 +3,10 @@
 from abc import ABC, abstractmethod
 from typing import Optional, Sequence
 
+from pydantic import BaseModel
+
 from langchain_core.callbacks import Callbacks
 from langchain_core.documents import Document
-from langchain_core.pydantic_v1 import BaseModel
 from langchain_core.runnables import run_in_executor
 
 

libs/core/langchain_core/embeddings/fake.py

@@ -4,8 +4,9 @@
 import hashlib
 from typing import List
 
+from pydantic import BaseModel
+
 from langchain_core.embeddings import Embeddings
-from langchain_core.pydantic_v1 import BaseModel
 
 
 class FakeEmbeddings(Embeddings, BaseModel):

libs/core/langchain_core/example_selectors/length_based.py

@@ -3,9 +3,10 @@
 import re
 from typing import Callable, Dict, List
 
+from pydantic import BaseModel, validator
+
 from langchain_core.example_selectors.base import BaseExampleSelector
 from langchain_core.prompts.prompt import PromptTemplate
-from langchain_core.pydantic_v1 import BaseModel, validator
 
 
 def _get_length_based(text: str) -> int:

libs/core/langchain_core/example_selectors/semantic_similarity.py

@@ -5,9 +5,10 @@
 from abc import ABC
 from typing import TYPE_CHECKING, Any, Dict, List, Optional, Type
 
+from pydantic import BaseModel, ConfigDict
+
 from langchain_core.documents import Document
 from langchain_core.example_selectors.base import BaseExampleSelector
-from langchain_core.pydantic_v1 import BaseModel, Extra
 from langchain_core.vectorstores import VectorStore
 
 if TYPE_CHECKING:
@@ -42,9 +43,10 @@ class _VectorStoreExampleSelector(BaseExampleSelector, BaseModel, ABC):
     vectorstore_kwargs: Optional[Dict[str, Any]] = None
     """Extra arguments passed to similarity_search function of the vectorstore."""
 
-    class Config:
-        arbitrary_types_allowed = True
-        extra = Extra.forbid
+    model_config = ConfigDict(
+        arbitrary_types_allowed=True,
+        extra="forbid",
+    )
 
     @staticmethod
     def _example_to_text(

libs/core/langchain_core/graph_vectorstores/base.py

@@ -12,6 +12,8 @@
     Optional,
 )
 
+from pydantic import Field
+
 from langchain_core._api import beta
 from langchain_core.callbacks import (
     AsyncCallbackManagerForRetrieverRun,
@@ -20,7 +22,6 @@
 from langchain_core.documents import Document
 from langchain_core.graph_vectorstores.links import METADATA_LINKS_KEY, Link
 from langchain_core.load import Serializable
-from langchain_core.pydantic_v1 import Field
 from langchain_core.runnables import run_in_executor
 from langchain_core.vectorstores import VectorStore, VectorStoreRetriever
 

libs/core/langchain_core/indexing/api.py

@@ -25,10 +25,11 @@
     cast,
 )
 
+from pydantic import model_validator
+
 from langchain_core.document_loaders.base import BaseLoader
 from langchain_core.documents import Document
 from langchain_core.indexing.base import DocumentIndex, RecordManager
-from langchain_core.pydantic_v1 import root_validator
 from langchain_core.vectorstores import VectorStore
 
 # Magic UUID to use as a namespace for hashing.
@@ -68,8 +69,9 @@ class _HashedDocument(Document):
     def is_lc_serializable(cls) -> bool:
         return False
 
-    @root_validator(pre=True)
-    def calculate_hashes(cls, values: Dict[str, Any]) -> Dict[str, Any]:
+    @model_validator(mode="before")
+    @classmethod
+    def calculate_hashes(cls, values: Dict[str, Any]) -> Any:
         """Root validator to calculate content and metadata hash."""
         content = values.get("page_content", "")
         metadata = values.get("metadata", {})

libs/core/langchain_core/indexing/in_memory.py

@@ -1,12 +1,13 @@
 import uuid
 from typing import Any, Dict, List, Optional, Sequence, cast
 
+from pydantic import Field
+
 from langchain_core._api import beta
 from langchain_core.callbacks import CallbackManagerForRetrieverRun
 from langchain_core.documents import Document
 from langchain_core.indexing import UpsertResponse
 from langchain_core.indexing.base import DeleteResponse, DocumentIndex
-from langchain_core.pydantic_v1 import Field
 
 
 @beta(message="Introduced in version 0.2.29. Underlying abstraction subject to change.")

libs/core/langchain_core/language_models/base.py

@@ -18,6 +18,7 @@
     Union,
 )
 
+from pydantic import BaseModel, ConfigDict, Field, validator
 from typing_extensions import TypeAlias, TypedDict
 
 from langchain_core._api import deprecated
@@ -28,7 +29,6 @@
     get_buffer_string,
 )
 from langchain_core.prompt_values import PromptValue
-from langchain_core.pydantic_v1 import BaseModel, Field, validator
 from langchain_core.runnables import Runnable, RunnableSerializable
 from langchain_core.utils import get_pydantic_field_names
 
@@ -113,7 +113,11 @@ class BaseLanguageModel(
 
     Caching is not currently supported for streaming methods of models.
     """
-    verbose: bool = Field(default_factory=_get_verbosity)
+    # Repr = False is consistent with pydantic 1 if verbose = False
+    # We can relax this for pydantic 2?
+    # TODO(Team): decide what to do here.
+    # Modified just to get unit tests to pass.
+    verbose: bool = Field(default_factory=_get_verbosity, exclude=True, repr=False)
     """Whether to print out response text."""
     callbacks: Callbacks = Field(default=None, exclude=True)
     """Callbacks to add to the run trace."""
@@ -126,6 +130,10 @@ class BaseLanguageModel(
     )
     """Optional encoder to use for counting tokens."""
 
+    model_config = ConfigDict(
+        arbitrary_types_allowed=True,
+    )
+
     @validator("verbose", pre=True, always=True, allow_reuse=True)
     def set_verbose(cls, verbose: Optional[bool]) -> bool:
         """If verbose is None, set it.

libs/core/langchain_core/language_models/chat_models.py

@@ -23,6 +23,13 @@
     cast,
 )
 
+from pydantic import (
+    BaseModel,
+    ConfigDict,
+    Field,
+    model_validator,
+)
+
 from langchain_core._api import deprecated
 from langchain_core.caches import BaseCache
 from langchain_core.callbacks import (
@@ -57,11 +64,6 @@
     RunInfo,
 )
 from langchain_core.prompt_values import ChatPromptValue, PromptValue, StringPromptValue
-from langchain_core.pydantic_v1 import (
-    BaseModel,
-    Field,
-    root_validator,
-)
 from langchain_core.rate_limiters import BaseRateLimiter
 from langchain_core.runnables import RunnableMap, RunnablePassthrough
 from langchain_core.runnables.config import ensure_config, run_in_executor
@@ -193,14 +195,20 @@ class BaseChatModel(BaseLanguageModel[BaseMessage], ABC):
 
     """  # noqa: E501
 
-    callback_manager: Optional[BaseCallbackManager] = deprecated(
-        name="callback_manager", since="0.1.7", removal="1.0", alternative="callbacks"
-    )(
-        Field(
-            default=None,
-            exclude=True,
-            description="Callback manager to add to the run trace.",
-        )
+    # TODO(0.3): Figure out how to re-apply deprecated decorator
+    # callback_manager: Optional[BaseCallbackManager] = deprecated(
+    #     name="callback_manager", since="0.1.7", removal="1.0", alternative="callbacks"
+    # )(
+    #     Field(
+    #         default=None,
+    #         exclude=True,
+    #         description="Callback manager to add to the run trace.",
+    #     )
+    # )
+    callback_manager: Optional[BaseCallbackManager] = Field(
+        default=None,
+        exclude=True,
+        description="Callback manager to add to the run trace.",
     )
 
     rate_limiter: Optional[BaseRateLimiter] = Field(default=None, exclude=True)
@@ -218,8 +226,9 @@ class BaseChatModel(BaseLanguageModel[BaseMessage], ABC):
     - If False (default), will always use streaming case if available.
     """
 
-    @root_validator(pre=True)
-    def raise_deprecation(cls, values: Dict) -> Dict:
+    @model_validator(mode="before")
+    @classmethod
+    def raise_deprecation(cls, values: Dict) -> Any:
         """Raise deprecation warning if callback_manager is used.
 
         Args:
@@ -240,8 +249,9 @@ def raise_deprecation(cls, values: Dict) -> Dict:
             values["callbacks"] = values.pop("callback_manager", None)
         return values
 
-    class Config:
-        arbitrary_types_allowed = True
+    model_config = ConfigDict(
+        arbitrary_types_allowed=True,
+    )
 
     # --- Runnable methods ---
 

libs/core/langchain_core/language_models/llms.py

@@ -27,6 +27,7 @@
 )
 
 import yaml
+from pydantic import ConfigDict, Field, model_validator
 from tenacity import (
     RetryCallState,
     before_sleep_log,
@@ -62,7 +63,6 @@
 )
 from langchain_core.outputs import Generation, GenerationChunk, LLMResult, RunInfo
 from langchain_core.prompt_values import ChatPromptValue, PromptValue, StringPromptValue
-from langchain_core.pydantic_v1 import Field, root_validator
 from langchain_core.runnables import RunnableConfig, ensure_config, get_config_list
 from langchain_core.runnables.config import run_in_executor
 
@@ -300,11 +300,13 @@ class BaseLLM(BaseLanguageModel[str], ABC):
     callback_manager: Optional[BaseCallbackManager] = Field(default=None, exclude=True)
     """[DEPRECATED]"""
 
-    class Config:
-        arbitrary_types_allowed = True
+    model_config = ConfigDict(
+        arbitrary_types_allowed=True,
+    )
 
-    @root_validator(pre=True)
-    def raise_deprecation(cls, values: Dict) -> Dict:
+    @model_validator(mode="before")
+    @classmethod
+    def raise_deprecation(cls, values: Dict) -> Any:
         """Raise deprecation warning if callback_manager is used."""
         if values.get("callback_manager") is not None:
             warnings.warn(