feat(core): deprecate problematic dict() method (#31685)

`dict()` is a problematic method name as it clashes with the builtin
`dict` used as a type annotation.
This PR replaces it with an `asdict` method (inspired by dataclasses).
It also fixes a few places where `dict` must be replaced by
`builtins.dict` until the `dict()` method is removed.

---------

Co-authored-by: Mason Daugherty <github@mdrxy.com>

libs/core/langchain_core/_api/deprecation.py

@@ -15,6 +15,7 @@ import inspect
 import sys
 import warnings
 from collections.abc import Callable, Generator
+from contextvars import ContextVar
 from typing import (
     TYPE_CHECKING,
     Any,
@@ -75,6 +76,15 @@ class LangChainPendingDeprecationWarning(PendingDeprecationWarning):
     """A class for issuing deprecation warnings for LangChain users."""
 
 
+# Tracks when callers intentionally silence LangChain deprecation warnings.
+# Suppressed warnings should not consume a deprecated callable's one-time
+# warning state; otherwise an internal compatibility path can prevent the first
+# user-visible call from warning.
+_SUPPRESSING_LANGCHAIN_DEPRECATION_WARNING = ContextVar(
+    "_SUPPRESSING_LANGCHAIN_DEPRECATION_WARNING", default=False
+)
+
+
 # PUBLIC API
 
 
@@ -220,16 +230,20 @@ def deprecated(
             """
             nonlocal warned
             if not warned and not is_caller_internal():
-                warned = True
                 emit_warning()
+                # Only mark the warning as emitted if it was not intentionally
+                # suppressed by `suppress_langchain_deprecation_warning()`.
+                warned = not _SUPPRESSING_LANGCHAIN_DEPRECATION_WARNING.get()
             return wrapped(*args, **kwargs)
 
         async def awarning_emitting_wrapper(*args: Any, **kwargs: Any) -> Any:
             """Same as warning_emitting_wrapper, but for async functions."""
             nonlocal warned
             if not warned and not is_caller_internal():
-                warned = True
                 emit_warning()
+                # Only mark the warning as emitted if it was not intentionally
+                # suppressed by `suppress_langchain_deprecation_warning()`.
+                warned = not _SUPPRESSING_LANGCHAIN_DEPRECATION_WARNING.get()
             return await wrapped(*args, **kwargs)
 
         _package = _package or obj.__module__.split(".")[0].replace("_", "-")
@@ -253,8 +267,10 @@ def deprecated(
                     """Warn that the class is in beta."""
                     nonlocal warned
                     if not warned and type(self) is obj and not is_caller_internal():
-                        warned = True
                         emit_warning()
+                        # Only mark the warning as emitted if it was not intentionally
+                        # suppressed by `suppress_langchain_deprecation_warning()`.
+                        warned = not _SUPPRESSING_LANGCHAIN_DEPRECATION_WARNING.get()
                     return wrapped(self, *args, **kwargs)
 
                 obj.__init__ = functools.wraps(obj.__init__)(  # type: ignore[misc]
@@ -451,10 +467,14 @@ def deprecated(
 @contextlib.contextmanager
 def suppress_langchain_deprecation_warning() -> Generator[None, None, None]:
     """Context manager to suppress `LangChainDeprecationWarning`."""
+    token = _SUPPRESSING_LANGCHAIN_DEPRECATION_WARNING.set(True)
+    try:
         with warnings.catch_warnings():
             warnings.simplefilter("ignore", LangChainDeprecationWarning)
             warnings.simplefilter("ignore", LangChainPendingDeprecationWarning)
             yield
+    finally:
+        _SUPPRESSING_LANGCHAIN_DEPRECATION_WARNING.reset(token)
 
 
 def warn_deprecated(

libs/core/langchain_core/language_models/chat_models.py

@@ -3,6 +3,7 @@
 from __future__ import annotations
 
 import asyncio
+import builtins  # noqa: TC003
 import contextlib
 import inspect
 import json
@@ -16,7 +17,7 @@ from langchain_protocol.protocol import MessageFinishData
 from pydantic import BaseModel, ConfigDict, Field, model_validator
 from typing_extensions import Self, override
 
-from langchain_core._api import beta
+from langchain_core._api import beta, deprecated, suppress_langchain_deprecation_warning
 from langchain_core.caches import BaseCache
 from langchain_core.callbacks import (
     AsyncCallbackManager,
@@ -93,7 +94,6 @@ from langchain_core.utils.pydantic import TypeBaseModel, is_basemodel_subclass
 from langchain_core.utils.utils import LC_ID_PREFIX, from_env
 
 if TYPE_CHECKING:
-    import builtins
     import uuid
     from collections.abc import Awaitable
 
@@ -430,11 +430,11 @@ class BaseChatModel(BaseLanguageModel[AIMessage], ABC):
         return self
 
     @cached_property
-    def _serialized(self) -> dict[str, Any]:
+    def _serialized(self) -> builtins.dict[str, Any]:
         # self is always a Serializable object in this case, thus the result is
-        # guaranteed to be a dict since dumps uses the default callback, which uses
+        # guaranteed to be a dict since dumpd uses the default callback, which uses
         # obj.to_json which always returns TypedDict subclasses
-        return cast("dict[str, Any]", dumpd(self))
+        return cast("builtins.dict[str, Any]", dumpd(self))
 
     # --- Runnable methods ---
 
@@ -1371,7 +1371,9 @@ class BaseChatModel(BaseLanguageModel[AIMessage], ABC):
 
     # --- Custom methods ---
 
-    def _combine_llm_outputs(self, _llm_outputs: list[dict | None], /) -> dict:
+    def _combine_llm_outputs(
+        self, _llm_outputs: list[builtins.dict | None], /
+    ) -> builtins.dict:
         return {}
 
     def _convert_cached_generations(self, cache_val: list) -> list[ChatGeneration]:
@@ -1464,8 +1466,8 @@ class BaseChatModel(BaseLanguageModel[AIMessage], ABC):
         self,
         stop: list[str] | None = None,
         **kwargs: Any,
-    ) -> dict:
+    ) -> builtins.dict:
-        params = self.dict()
+        params = self._dict_for_compat()
         params["stop"] = stop
         return {**params, **kwargs}
 
@@ -1566,7 +1568,7 @@ class BaseChatModel(BaseLanguageModel[AIMessage], ABC):
         callbacks: Callbacks = None,
         *,
         tags: list[str] | None = None,
-        metadata: dict[str, Any] | None = None,
+        metadata: builtins.dict[str, Any] | None = None,
         run_name: str | None = None,
         run_id: uuid.UUID | None = None,
         **kwargs: Any,
@@ -1692,7 +1694,7 @@ class BaseChatModel(BaseLanguageModel[AIMessage], ABC):
         callbacks: Callbacks = None,
         *,
         tags: list[str] | None = None,
-        metadata: dict[str, Any] | None = None,
+        metadata: builtins.dict[str, Any] | None = None,
         run_name: str | None = None,
         run_id: uuid.UUID | None = None,
         **kwargs: Any,
@@ -2303,13 +2305,26 @@ class BaseChatModel(BaseLanguageModel[AIMessage], ABC):
     def _llm_type(self) -> str:
         """Return type of chat model."""
 
+    @deprecated("1.4.2", alternative="asdict", removal="2.0.0")
     @override
-    def dict(self, **kwargs: Any) -> dict:
+    def dict(self, **_kwargs: Any) -> builtins.dict[str, Any]:
-        """Return a dictionary of the LLM."""
+        """DEPRECATED - use `asdict()` instead.
+
+        Return a dictionary representation of the chat model.
+        """
+        return self.asdict()
+
+    def asdict(self) -> builtins.dict[str, Any]:
+        """Return a dictionary representation of the chat model."""
         starter_dict = dict(self._identifying_params)
         starter_dict["_type"] = self._llm_type
         return starter_dict
 
+    def _dict_for_compat(self) -> builtins.dict[str, Any]:
+        """Return the chat model dictionary while preserving deprecated overrides."""
+        with suppress_langchain_deprecation_warning():
+            return self.dict()
+
     @override
     def bind(self, **kwargs: Any) -> _ChatModelBinding:
         """Bind kwargs to this chat model, returning a typed `_ChatModelBinding`.

libs/core/langchain_core/language_models/llms.py

@@ -6,6 +6,7 @@ These are traditionally older models (newer models generally are chat models).
 from __future__ import annotations
 
 import asyncio
+import builtins  # noqa: TC003
 import functools
 import inspect
 import json
@@ -32,6 +33,7 @@ from tenacity import (
 )
 from typing_extensions import override
 
+from langchain_core._api import deprecated, suppress_langchain_deprecation_warning
 from langchain_core.caches import BaseCache
 from langchain_core.callbacks import (
     AsyncCallbackManager,
@@ -301,11 +303,11 @@ class BaseLLM(BaseLanguageModel[str], ABC):
     )
 
     @functools.cached_property
-    def _serialized(self) -> dict[str, Any]:
+    def _serialized(self) -> builtins.dict[str, Any]:
         # self is always a Serializable object in this case, thus the result is
-        # guaranteed to be a dict since dumps uses the default callback, which uses
+        # guaranteed to be a dict since dumpd uses the default callback, which uses
         # obj.to_json which always returns TypedDict subclasses
-        return cast("dict[str, Any]", dumpd(self))
+        return cast("builtins.dict[str, Any]", dumpd(self))
 
     # --- Runnable methods ---
 
@@ -522,7 +524,7 @@ class BaseLLM(BaseLanguageModel[str], ABC):
         else:
             prompt = self._convert_input(input).to_string()
             config = ensure_config(config)
-            params = self.dict()
+            params = self._dict_for_compat()
             params["stop"] = stop
             params = {**params, **kwargs}
             options = {"stop": stop}
@@ -595,7 +597,7 @@ class BaseLLM(BaseLanguageModel[str], ABC):
 
         prompt = self._convert_input(input).to_string()
         config = ensure_config(config)
-        params = self.dict()
+        params = self._dict_for_compat()
         params["stop"] = stop
         params = {**params, **kwargs}
         options = {"stop": stop}
@@ -853,7 +855,7 @@ class BaseLLM(BaseLanguageModel[str], ABC):
         callbacks: Callbacks | list[Callbacks] | None = None,
         *,
         tags: list[str] | list[list[str]] | None = None,
-        metadata: dict[str, Any] | list[dict[str, Any]] | None = None,
+        metadata: builtins.dict[str, Any] | list[builtins.dict[str, Any]] | None = None,
         run_name: str | list[str] | None = None,
         run_id: uuid.UUID | list[uuid.UUID | None] | None = None,
         **kwargs: Any,
@@ -957,7 +959,7 @@ class BaseLLM(BaseLanguageModel[str], ABC):
             run_name_list = run_name or cast(
                 "list[str | None]", ([None] * len(prompts))
             )
-            params = self.dict()
+            params = self._dict_for_compat()
             params["stop"] = stop
             callback_managers = [
                 CallbackManager.configure(
@@ -978,7 +980,7 @@ class BaseLLM(BaseLanguageModel[str], ABC):
             ]
         else:
             # We've received a single callbacks arg to apply to all inputs
-            params = self.dict()
+            params = self._dict_for_compat()
             params["stop"] = stop
             callback_managers = [
                 CallbackManager.configure(
@@ -1136,7 +1138,7 @@ class BaseLLM(BaseLanguageModel[str], ABC):
         callbacks: Callbacks | list[Callbacks] | None = None,
         *,
         tags: list[str] | list[list[str]] | None = None,
-        metadata: dict[str, Any] | list[dict[str, Any]] | None = None,
+        metadata: builtins.dict[str, Any] | list[builtins.dict[str, Any]] | None = None,
         run_name: str | list[str] | None = None,
         run_id: uuid.UUID | list[uuid.UUID | None] | None = None,
         **kwargs: Any,
@@ -1229,7 +1231,7 @@ class BaseLLM(BaseLanguageModel[str], ABC):
             run_name_list = run_name or cast(
                 "list[str | None]", ([None] * len(prompts))
             )
-            params = self.dict()
+            params = self._dict_for_compat()
             params["stop"] = stop
             callback_managers = [
                 AsyncCallbackManager.configure(
@@ -1250,7 +1252,7 @@ class BaseLLM(BaseLanguageModel[str], ABC):
             ]
         else:
             # We've received a single callbacks arg to apply to all inputs
-            params = self.dict()
+            params = self._dict_for_compat()
             params["stop"] = stop
             callback_managers = [
                 AsyncCallbackManager.configure(
@@ -1358,7 +1360,7 @@ class BaseLLM(BaseLanguageModel[str], ABC):
         callbacks: Callbacks = None,
         *,
         tags: list[str] | None = None,
-        metadata: dict[str, Any] | None = None,
+        metadata: builtins.dict[str, Any] | None = None,
         **kwargs: Any,
     ) -> str:
         """Check Cache and run the LLM on the given prompt and input."""
@@ -1382,13 +1384,26 @@ class BaseLLM(BaseLanguageModel[str], ABC):
     def _llm_type(self) -> str:
         """Return type of llm."""
 
+    @deprecated("1.4.2", alternative="asdict", removal="2.0.0")
     @override
-    def dict(self, **kwargs: Any) -> dict:
+    def dict(self, **_kwargs: Any) -> builtins.dict[str, Any]:
-        """Return a dictionary of the LLM."""
+        """DEPRECATED - use `asdict()` instead.
+
+        Return a dictionary representation of the LLM.
+        """
+        return self.asdict()
+
+    def asdict(self) -> builtins.dict[str, Any]:
+        """Return a dictionary representation of the LLM."""
         starter_dict = dict(self._identifying_params)
         starter_dict["_type"] = self._llm_type
         return starter_dict
 
+    def _dict_for_compat(self) -> builtins.dict[str, Any]:
+        """Return the LLM dictionary while preserving deprecated overrides."""
+        with suppress_langchain_deprecation_warning():
+            return self.dict()
+
     def save(self, file_path: Path | str) -> None:
         """Save the LLM.
 
@@ -1410,7 +1425,7 @@ class BaseLLM(BaseLanguageModel[str], ABC):
         directory_path.mkdir(parents=True, exist_ok=True)
 
         # Fetch dictionary to save
-        prompt_dict = self.dict()
+        prompt_dict = self._dict_for_compat()
 
         if save_path.suffix == ".json":
             with save_path.open("w", encoding="utf-8") as f:

libs/core/langchain_core/output_parsers/base.py

@@ -2,6 +2,7 @@
 
 from __future__ import annotations
 
+import builtins  # noqa: TC003
 import contextlib
 from abc import ABC, abstractmethod
 from typing import (
@@ -14,6 +15,7 @@ from typing import (
 
 from typing_extensions import override
 
+from langchain_core._api import deprecated
 from langchain_core.language_models import LanguageModelOutput
 from langchain_core.messages import AnyMessage, BaseMessage
 from langchain_core.outputs import ChatGeneration, Generation
@@ -340,8 +342,17 @@ class BaseOutputParser(
         )
         raise NotImplementedError(msg)
 
-    def dict(self, **kwargs: Any) -> dict:
+    @deprecated("1.4.2", alternative="asdict", removal="2.0.0")
-        """Return dictionary representation of output parser."""
+    @override
+    def dict(self, **kwargs: Any) -> builtins.dict[str, Any]:
+        """DEPRECATED - use `asdict()` instead.
+
+        Return a dictionary representation of the output parser.
+        """
+        return self.asdict(**kwargs)
+
+    def asdict(self, **kwargs: Any) -> builtins.dict[str, Any]:
+        """Return a dictionary representation of the output parser."""
         output_parser_dict = super().model_dump(**kwargs)
         with contextlib.suppress(NotImplementedError):
             output_parser_dict["_type"] = self._type

libs/core/langchain_core/prompts/base.py

@@ -2,11 +2,11 @@
 
 from __future__ import annotations
 
-import builtins  # noqa: TC003
+import builtins
 import contextlib
 import json
 from abc import ABC, abstractmethod
-from collections.abc import Mapping  # noqa: TC003
+from collections.abc import Callable, Mapping
 from functools import cached_property
 from pathlib import Path
 from typing import TYPE_CHECKING, Any, Generic, TypeVar, cast
@@ -15,22 +15,20 @@ import yaml
 from pydantic import BaseModel, ConfigDict, Field, model_validator
 from typing_extensions import Self, override
 
-from langchain_core._api import deprecated
+from langchain_core._api import deprecated, suppress_langchain_deprecation_warning
 from langchain_core.exceptions import ErrorCode, create_message
 from langchain_core.load import dumpd
-from langchain_core.output_parsers.base import BaseOutputParser  # noqa: TC001
+from langchain_core.output_parsers.base import BaseOutputParser
 from langchain_core.prompt_values import (
     ChatPromptValueConcrete,
     PromptValue,
     StringPromptValue,
 )
-from langchain_core.runnables import RunnableConfig, RunnableSerializable
+from langchain_core.runnables.base import RunnableSerializable
-from langchain_core.runnables.config import ensure_config
+from langchain_core.runnables.config import RunnableConfig, ensure_config
 from langchain_core.utils.pydantic import create_model_v2
 
 if TYPE_CHECKING:
-    from collections.abc import Callable
-
     from langchain_core.documents import Document
 
 
@@ -123,11 +121,11 @@ class BasePromptTemplate(
     )
 
     @cached_property
-    def _serialized(self) -> dict[str, Any]:
+    def _serialized(self) -> builtins.dict[str, Any]:
         # self is always a Serializable object in this case, thus the result is
         # guaranteed to be a dict since dumpd uses the default callback, which uses
         # obj.to_json which always returns TypedDict subclasses
-        return cast("dict[str, Any]", dumpd(self))
+        return cast("builtins.dict[str, Any]", dumpd(self))
 
     @property
     @override
@@ -157,7 +155,7 @@ class BasePromptTemplate(
             field_definitions={**required_input_variables, **optional_input_variables},
         )
 
-    def _validate_input(self, inner_input: Any) -> dict:
+    def _validate_input(self, inner_input: Any) -> builtins.dict:
         if not isinstance(inner_input, dict):
             if len(self.input_variables) == 1:
                 var_name = self.input_variables[0]
@@ -193,19 +191,23 @@ class BasePromptTemplate(
             )
         return inner_input_
 
-    def _format_prompt_with_error_handling(self, inner_input: dict) -> PromptValue:
+    def _format_prompt_with_error_handling(
+        self,
+        inner_input: builtins.dict,
+    ) -> PromptValue:
         inner_input_ = self._validate_input(inner_input)
         return self.format_prompt(**inner_input_)
 
     async def _aformat_prompt_with_error_handling(
-        self, inner_input: dict
+        self,
+        inner_input: builtins.dict,
     ) -> PromptValue:
         inner_input_ = self._validate_input(inner_input)
         return await self.aformat_prompt(**inner_input_)
 
     @override
     def invoke(
-        self, input: dict, config: RunnableConfig | None = None, **kwargs: Any
+        self, input: builtins.dict, config: RunnableConfig | None = None, **kwargs: Any
     ) -> PromptValue:
         """Invoke the prompt.
 
@@ -231,7 +233,7 @@ class BasePromptTemplate(
 
     @override
     async def ainvoke(
-        self, input: dict, config: RunnableConfig | None = None, **kwargs: Any
+        self, input: builtins.dict, config: RunnableConfig | None = None, **kwargs: Any
     ) -> PromptValue:
         """Async invoke the prompt.
 
@@ -293,7 +295,9 @@ class BasePromptTemplate(
         prompt_dict["partial_variables"] = {**self.partial_variables, **kwargs}
         return type(self)(**prompt_dict)
 
-    def _merge_partial_and_user_variables(self, **kwargs: Any) -> dict[str, Any]:
+    def _merge_partial_and_user_variables(
+        self, **kwargs: Any
+    ) -> builtins.dict[str, Any]:
         # Get partial params:
         partial_kwargs = {
             k: v if not callable(v) else v() for k, v in self.partial_variables.items()
@@ -337,8 +341,17 @@ class BasePromptTemplate(
         """Return the prompt type key."""
         raise NotImplementedError
 
-    def dict(self, **kwargs: Any) -> dict:
+    @deprecated("1.4.2", alternative="asdict", removal="2.0.0")
-        """Return dictionary representation of prompt.
+    @override
+    def dict(self, **kwargs: Any) -> builtins.dict[str, Any]:
+        """DEPRECATED - use `asdict()` instead.
+
+        Return a dictionary representation of the prompt.
+        """
+        return self.asdict(**kwargs)
+
+    def asdict(self, **kwargs: Any) -> builtins.dict[str, Any]:
+        """Return a dictionary representation of the prompt.
 
         Args:
             **kwargs: Any additional arguments to pass to the dictionary.
@@ -351,6 +364,11 @@ class BasePromptTemplate(
             prompt_dict["_type"] = self._prompt_type
         return prompt_dict
 
+    def _dict_for_compat(self) -> builtins.dict[str, Any]:
+        """Return the prompt dictionary while preserving deprecated overrides."""
+        with suppress_langchain_deprecation_warning():
+            return self.dict()
+
     @deprecated(
         since="1.2.21",
         removal="2.0.0",
@@ -377,8 +395,9 @@ class BasePromptTemplate(
             msg = "Cannot save prompt with partial variables."
             raise ValueError(msg)
 
-        # Fetch dictionary to save
+        # Fetch dictionary to save. Preserve deprecated `dict()` overrides until
-        prompt_dict = self.dict()
+        # `dict()` is removed.
+        prompt_dict = self._dict_for_compat()
         if "_type" not in prompt_dict:
             msg = f"Prompt {self} does not support saving."
             raise NotImplementedError(msg)

libs/core/tests/unit_tests/_api/test_deprecation.py

@@ -8,8 +8,10 @@ import pytest
 from pydantic import BaseModel
 
 from langchain_core._api.deprecation import (
+    LangChainDeprecationWarning,
     deprecated,
     rename_parameter,
+    suppress_langchain_deprecation_warning,
     warn_deprecated,
 )
 
@@ -130,6 +132,25 @@ class ClassWithDeprecatedMethods:
         return "This is a deprecated property."
 
 
+def test_suppressed_deprecation_warning_does_not_consume_warning() -> None:
+    """Suppressed calls should not block a later user-visible warning.
+
+    For example, an internal compatibility path may call a deprecated method while
+    saving/loading an object with warnings suppressed. That hidden call should not
+    prevent the user's later direct call from seeing the deprecation warning.
+    """
+
+    @deprecated(since="2.0.0", removal="3.0.0", pending=False)
+    def local_deprecated_function() -> str:
+        return "deprecated"
+
+    with suppress_langchain_deprecation_warning():
+        assert local_deprecated_function() == "deprecated"
+
+    with pytest.warns(LangChainDeprecationWarning):
+        assert local_deprecated_function() == "deprecated"
+
+
 def test_deprecated_function() -> None:
     """Test deprecated function."""
     with warnings.catch_warnings(record=True) as warning_list:

libs/core/tests/unit_tests/language_models/chat_models/test_base.py

@@ -4,13 +4,15 @@ import uuid
 import warnings
 from collections.abc import AsyncIterator, Iterator
 from contextlib import contextmanager
-from typing import TYPE_CHECKING, Any, Literal
+from typing import TYPE_CHECKING, Any, Literal, get_type_hints
 from unittest.mock import patch
 
 import pytest
+from langsmith.env import get_langchain_env_var_metadata
 from pydantic import model_validator
 from typing_extensions import Self, override
 
+from langchain_core._api import LangChainDeprecationWarning
 from langchain_core.callbacks import (
     AsyncCallbackManagerForLLMRun,
     BaseCallbackHandler,
@@ -92,6 +94,41 @@ def _content_blocks_equal_ignore_id(
     return True
 
 
+def test_asdict_replaces_deprecated_dict() -> None:
+    model = FakeListChatModel(responses=["foo"])
+
+    expected = {"responses": ["foo"], "_type": "fake-list-chat-model"}
+    assert model.asdict() == expected
+    with pytest.warns(LangChainDeprecationWarning, match="asdict"):
+        assert model.dict() == expected
+
+
+def test_base_chat_model_type_hints_resolve() -> None:
+    assert get_type_hints(BaseChatModel.asdict)["return"] == dict[str, Any]
+
+
+def test_invoke_preserves_deprecated_dict_override() -> None:
+    """Invoking should preserve `dict()` overrides until `dict()` is removed."""
+
+    class CustomDictChatModel(FakeListChatModel):
+        @override
+        def dict(self, **kwargs: Any) -> dict[str, Any]:
+            data = super().dict(**kwargs)
+            data["custom_trace_param"] = "custom"
+            return data
+
+    model = CustomDictChatModel(responses=["foo"])
+    with warnings.catch_warnings():
+        warnings.simplefilter("error", LangChainDeprecationWarning)
+        with collect_runs() as cb:
+            assert model.invoke("hello").content == "foo"
+
+    assert cb.traced_runs[0].extra is not None
+    assert cb.traced_runs[0].extra["invocation_params"]["custom_trace_param"] == (
+        "custom"
+    )
+
+
 @pytest.fixture
 def messages() -> list[BaseMessage]:
     return [
@@ -1529,10 +1566,12 @@ def test_invocation_params_passed_to_tracer_metadata() -> None:
     assert len(collector.runs) == 1
     run = collector.runs[0]
 
-    key = "LANGSMITH_LANGGRAPH_API_VARIANT"
+    # LangSmith injects environment-derived keys (e.g. `revision_id`,
-
+    # `LANGCHAIN_TESTS_USER_AGENT`, `LANGSMITH_*`) into run metadata. These vary
-    if key in run.extra["metadata"]:
+    # by environment and are not the subject of this test, so strip them before
-        del run.extra["metadata"][key]
+    # the exact-equality comparison.
+    for env_key in get_langchain_env_var_metadata():
+        run.extra["metadata"].pop(env_key, None)
 
     assert run.extra == {
         "batch_size": 1,
@@ -1551,7 +1590,6 @@ def test_invocation_params_passed_to_tracer_metadata() -> None:
             "ls_model_type": "chat",
             "ls_provider": "fakechatmodelwithinvocationparams",
             "ls_temperature": 0.7,
-            "revision_id": run.extra["metadata"]["revision_id"],
             "stop": None,
             "temperature": 0.7,
         },

libs/core/tests/unit_tests/language_models/llms/test_base.py

@@ -1,9 +1,11 @@
+import warnings
 from collections.abc import AsyncIterator, Iterator
-from typing import Any
+from typing import Any, get_type_hints
 
 import pytest
 from typing_extensions import override
 
+from langchain_core._api import LangChainDeprecationWarning
 from langchain_core.callbacks import (
     AsyncCallbackManagerForLLMRun,
     CallbackManagerForLLMRun,
@@ -23,6 +25,41 @@ from tests.unit_tests.fake.callbacks import (
 )
 
 
+def test_asdict_replaces_deprecated_dict() -> None:
+    llm = FakeListLLM(responses=["foo"])
+
+    expected = {"responses": ["foo"], "_type": "fake-list"}
+    assert llm.asdict() == expected
+    with pytest.warns(LangChainDeprecationWarning, match="asdict"):
+        assert llm.dict() == expected
+
+
+def test_base_llm_type_hints_resolve() -> None:
+    assert get_type_hints(BaseLLM.asdict)["return"] == dict[str, Any]
+
+
+def test_invoke_preserves_deprecated_dict_override() -> None:
+    """Invoking should preserve `dict()` overrides until `dict()` is removed."""
+
+    class CustomDictLLM(FakeListLLM):
+        @override
+        def dict(self, **kwargs: Any) -> dict[str, Any]:
+            data = super().dict(**kwargs)
+            data["custom_trace_param"] = "custom"
+            return data
+
+    llm = CustomDictLLM(responses=["foo"])
+    with warnings.catch_warnings():
+        warnings.simplefilter("error", LangChainDeprecationWarning)
+        with collect_runs() as cb:
+            assert llm.invoke("hello") == "foo"
+
+    assert cb.traced_runs[0].extra is not None
+    assert cb.traced_runs[0].extra["invocation_params"]["custom_trace_param"] == (
+        "custom"
+    )
+
+
 def test_batch() -> None:
     llm = FakeListLLM(responses=["foo"] * 3)
     output = llm.batch(["foo", "bar", "foo"])

libs/core/tests/unit_tests/output_parsers/test_base_parsers.py

@@ -1,17 +1,38 @@
 """Module to test base parser implementations."""
 
+from typing import Any, get_type_hints
+
+import pytest
 from typing_extensions import override
 
+from langchain_core._api import LangChainDeprecationWarning
 from langchain_core.exceptions import OutputParserException
 from langchain_core.language_models import GenericFakeChatModel
 from langchain_core.messages import AIMessage
 from langchain_core.output_parsers import (
     BaseGenerationOutputParser,
+    BaseOutputParser,
     BaseTransformOutputParser,
 )
 from langchain_core.outputs import ChatGeneration, Generation
 
 
+def test_asdict_replaces_deprecated_dict() -> None:
+    class StrInvertCase(BaseTransformOutputParser[str]):
+        def parse(self, text: str) -> str:
+            return text.swapcase()
+
+    parser = StrInvertCase()
+    parser_dict = parser.asdict(exclude_none=True)
+    assert parser_dict == {}
+    with pytest.warns(LangChainDeprecationWarning, match="asdict"):
+        assert parser.dict(exclude_none=True) == parser_dict
+
+
+def test_base_output_parser_type_hints_resolve() -> None:
+    assert get_type_hints(BaseOutputParser.asdict)["return"] == dict[str, Any]
+
+
 def test_base_generation_parser() -> None:
     """Test Base Generation Output Parser."""
 

libs/core/tests/unit_tests/prompts/test_loading.py

@@ -5,8 +5,10 @@ import os
 from collections.abc import Iterator
 from contextlib import contextmanager
 from pathlib import Path
+from typing import Any
 
 import pytest
+from typing_extensions import override
 
 from langchain_core._api import suppress_langchain_deprecation_warning
 from langchain_core.prompts.few_shot import FewShotPromptTemplate
@@ -105,6 +107,25 @@ def test_saving_loading_round_trip(tmp_path: Path) -> None:
     assert loaded_prompt == few_shot_prompt
 
 
+def test_save_preserves_deprecated_dict_override(tmp_path: Path) -> None:
+    """Saving should preserve `dict()` overrides until `dict()` is removed."""
+
+    class CustomDictPrompt(PromptTemplate):
+        @override
+        def dict(self, **kwargs: Any) -> dict[str, Any]:
+            data = super().dict(**kwargs)
+            data["custom_save_param"] = "custom"
+            return data
+
+    prompt = CustomDictPrompt(input_variables=["name"], template="Hello {name}")
+    output_path = tmp_path / "prompt.json"
+
+    with suppress_langchain_deprecation_warning():
+        prompt.save(output_path)
+
+    assert json.loads(output_path.read_text())["custom_save_param"] == "custom"
+
+
 def test_loading_with_template_as_file() -> None:
     """Test loading when the template is a file."""
     with change_directory(EXAMPLE_DIR), suppress_langchain_deprecation_warning():

libs/core/tests/unit_tests/prompts/test_prompt.py

@@ -9,6 +9,7 @@ import pytest
 from packaging import version
 from syrupy.assertion import SnapshotAssertion
 
+from langchain_core._api import LangChainDeprecationWarning
 from langchain_core.prompts.prompt import PromptTemplate
 from langchain_core.prompts.string import PromptTemplateFormat
 from langchain_core.tracers.run_collector import RunCollectorCallbackHandler
@@ -18,6 +19,15 @@ from tests.unit_tests.pydantic_utils import _normalize_schema
 PYDANTIC_VERSION_AT_LEAST_29 = version.parse("2.9") <= PYDANTIC_VERSION
 
 
+def test_asdict_replaces_deprecated_dict() -> None:
+    prompt = PromptTemplate.from_template("This is a {foo} test.")
+
+    prompt_dict = prompt.asdict()
+    assert prompt_dict["_type"] == "prompt"
+    with pytest.warns(LangChainDeprecationWarning, match="asdict"):
+        assert prompt.dict() == prompt_dict
+
+
 def test_prompt_valid() -> None:
     """Test prompts can be constructed."""
     template = "This is a {foo} test."
@@ -217,11 +227,7 @@ def test_mustache_prompt_from_template(snapshot: SnapshotAssertion) -> None:
     {{/foo}}is a test."""
     prompt = PromptTemplate.from_template(template, template_format="mustache")
     assert prompt.format(foo=[{"bar": "yo"}, {"bar": "hello"}]) == (
-        """This
+        "This\n        yo\n    \n        hello\n    is a test."
-        yo
-    
-        hello
-    is a test."""  # noqa: W293
     )
     assert prompt.input_variables == ["foo"]
     if PYDANTIC_VERSION_AT_LEAST_29: