Preparation for 0.5 release: langgraph-checkpoint (#5124)

Prepare langgraph-checkpoint for 0.5

- Given we have no upper bound on langgraph-checkpoint dep need to undo all changes in langgraph-checkpoint that might break previous versions of langgraph

libs/checkpoint-postgres/langgraph/checkpoint/postgres/base.py

@@ -168,7 +168,7 @@ class BasePostgresSaver(BaseCheckpointSaver[str]):
         checkpoint["channel_versions"][TASKS] = (
             max(checkpoint["channel_versions"].values())
             if checkpoint["channel_versions"]
-            else self.get_next_version(None)
+            else self.get_next_version(None, None)
         )
 
     def _load_blobs(
@@ -246,7 +246,7 @@ class BasePostgresSaver(BaseCheckpointSaver[str]):
             for idx, (channel, value) in enumerate(writes)
         ]
 
-    def get_next_version(self, current: str | None) -> str:
+    def get_next_version(self, current: str | None, channel: None) -> str:
         if current is None:
             current_v = 0
         elif isinstance(current, int):

libs/checkpoint-postgres/tests/checkpoint_utils.py

@@ -1,53 +0,0 @@
-from __future__ import annotations
-
-from collections.abc import Mapping
-from datetime import datetime, timezone
-from typing import Any, Protocol
-
-from langgraph.checkpoint.base import Checkpoint, EmptyChannelError
-from langgraph.checkpoint.base.id import uuid6
-
-
-class ChannelProtocol(Protocol):
-    def checkpoint(self) -> Any | None: ...
-
-
-def empty_checkpoint() -> Checkpoint:
-    return Checkpoint(
-        v=1,
-        id=str(uuid6(clock_seq=-2)),
-        ts=datetime.now(timezone.utc).isoformat(),
-        channel_values={},
-        channel_versions={},
-        versions_seen={},
-    )
-
-
-def create_checkpoint(
-    checkpoint: Checkpoint,
-    channels: Mapping[str, ChannelProtocol] | None,
-    step: int,
-    *,
-    id: str | None = None,
-) -> Checkpoint:
-    """Create a checkpoint for the given channels."""
-    ts = datetime.now(timezone.utc).isoformat()
-    if channels is None:
-        values = checkpoint["channel_values"]
-    else:
-        values = {}
-        for k, v in channels.items():
-            if k not in checkpoint["channel_versions"]:
-                continue
-            try:
-                values[k] = v.checkpoint()
-            except EmptyChannelError:
-                pass
-    return Checkpoint(
-        v=1,
-        ts=ts,
-        id=id or str(uuid6(clock_seq=step)),
-        channel_values=values,
-        channel_versions=checkpoint["channel_versions"],
-        versions_seen=checkpoint["versions_seen"],
-    )

libs/checkpoint-postgres/tests/test_async.py

@@ -14,13 +14,14 @@ from langgraph.checkpoint.base import (
     EXCLUDED_METADATA_KEYS,
     Checkpoint,
     CheckpointMetadata,
+    create_checkpoint,
+    empty_checkpoint,
 )
 from langgraph.checkpoint.postgres.aio import (
     AsyncPostgresSaver,
     AsyncShallowPostgresSaver,
 )
 from langgraph.checkpoint.serde.types import TASKS
-from tests.checkpoint_utils import create_checkpoint, empty_checkpoint
 from tests.conftest import DEFAULT_POSTGRES_URI
 
 

libs/checkpoint-postgres/tests/test_sync.py

@@ -15,10 +15,11 @@ from langgraph.checkpoint.base import (
     EXCLUDED_METADATA_KEYS,
     Checkpoint,
     CheckpointMetadata,
+    create_checkpoint,
+    empty_checkpoint,
 )
 from langgraph.checkpoint.postgres import PostgresSaver, ShallowPostgresSaver
 from langgraph.checkpoint.serde.types import TASKS
-from tests.checkpoint_utils import create_checkpoint, empty_checkpoint
 from tests.conftest import DEFAULT_POSTGRES_URI
 
 

libs/checkpoint-sqlite/langgraph/checkpoint/sqlite/__init__.py

@@ -536,7 +536,7 @@ class SqliteSaver(BaseCheckpointSaver[str]):
         """
         raise NotImplementedError(_AIO_ERROR_MSG)
 
-    def get_next_version(self, current: str | None) -> str:
+    def get_next_version(self, current: str | None, channel: None) -> str:
         """Generate the next version ID for a channel.
 
         This method creates a new version identifier for a channel based on its current version.

libs/checkpoint-sqlite/langgraph/checkpoint/sqlite/aio.py

@@ -591,7 +591,7 @@ class AsyncSqliteSaver(BaseCheckpointSaver[str]):
             )
             await self.conn.commit()
 
-    def get_next_version(self, current: str | None) -> str:
+    def get_next_version(self, current: str | None, channel: None) -> str:
         """Generate the next version ID for a channel.
 
         This method creates a new version identifier for a channel based on its current version.

libs/checkpoint-sqlite/tests/checkpoint_utils.py

@@ -1,53 +0,0 @@
-from __future__ import annotations
-
-from collections.abc import Mapping
-from datetime import datetime, timezone
-from typing import Any, Protocol
-
-from langgraph.checkpoint.base import Checkpoint, EmptyChannelError
-from langgraph.checkpoint.base.id import uuid6
-
-
-class ChannelProtocol(Protocol):
-    def checkpoint(self) -> Any | None: ...
-
-
-def empty_checkpoint() -> Checkpoint:
-    return Checkpoint(
-        v=1,
-        id=str(uuid6(clock_seq=-2)),
-        ts=datetime.now(timezone.utc).isoformat(),
-        channel_values={},
-        channel_versions={},
-        versions_seen={},
-    )
-
-
-def create_checkpoint(
-    checkpoint: Checkpoint,
-    channels: Mapping[str, ChannelProtocol] | None,
-    step: int,
-    *,
-    id: str | None = None,
-) -> Checkpoint:
-    """Create a checkpoint for the given channels."""
-    ts = datetime.now(timezone.utc).isoformat()
-    if channels is None:
-        values = checkpoint["channel_values"]
-    else:
-        values = {}
-        for k, v in channels.items():
-            if k not in checkpoint["channel_versions"]:
-                continue
-            try:
-                values[k] = v.checkpoint()
-            except EmptyChannelError:
-                pass
-    return Checkpoint(
-        v=1,
-        ts=ts,
-        id=id or str(uuid6(clock_seq=step)),
-        channel_values=values,
-        channel_versions=checkpoint["channel_versions"],
-        versions_seen=checkpoint["versions_seen"],
-    )

libs/checkpoint-sqlite/tests/test_aiosqlite.py

@@ -6,9 +6,10 @@ from langchain_core.runnables import RunnableConfig
 from langgraph.checkpoint.base import (
     Checkpoint,
     CheckpointMetadata,
+    create_checkpoint,
+    empty_checkpoint,
 )
 from langgraph.checkpoint.sqlite.aio import AsyncSqliteSaver
-from tests.checkpoint_utils import create_checkpoint, empty_checkpoint
 
 
 class TestAsyncSqliteSaver:

libs/checkpoint-sqlite/tests/test_sqlite.py

@@ -6,10 +6,11 @@ from langchain_core.runnables import RunnableConfig
 from langgraph.checkpoint.base import (
     Checkpoint,
     CheckpointMetadata,
+    create_checkpoint,
+    empty_checkpoint,
 )
 from langgraph.checkpoint.sqlite import SqliteSaver
 from langgraph.checkpoint.sqlite.utils import _metadata_predicate, search_where
-from tests.checkpoint_utils import create_checkpoint, empty_checkpoint
 
 
 class TestSqliteSaver:

libs/checkpoint/langgraph/checkpoint/base/__init__.py

@@ -1,10 +1,8 @@
 from __future__ import annotations
 
-from collections.abc import AsyncIterator, Iterator, Sequence
-from inspect import signature
+from collections.abc import AsyncIterator, Iterator, Mapping, Sequence
 from typing import (  # noqa: UP035
     Any,
-    ClassVar,
     Generic,
     Literal,
     NamedTuple,
@@ -15,6 +13,7 @@ from typing import (  # noqa: UP035
 
 from langchain_core.runnables import RunnableConfig
 
+from langgraph.checkpoint.base.id import uuid6
 from langgraph.checkpoint.serde.base import SerializerProtocol, maybe_add_typed_methods
 from langgraph.checkpoint.serde.jsonplus import JsonPlusSerializer
 from langgraph.checkpoint.serde.types import (
@@ -22,6 +21,7 @@ from langgraph.checkpoint.serde.types import (
     INTERRUPT,
     RESUME,
     SCHEDULED,
+    ChannelProtocol,
 )
 
 V = TypeVar("V", int, float, str)
@@ -91,6 +91,7 @@ def copy_checkpoint(checkpoint: Checkpoint) -> Checkpoint:
         channel_values=checkpoint["channel_values"].copy(),
         channel_versions=checkpoint["channel_versions"].copy(),
         versions_seen={k: v.copy() for k, v in checkpoint["versions_seen"].items()},
+        pending_sends=checkpoint.get("pending_sends", []).copy(),
     )
 
 
@@ -118,19 +119,8 @@ class BaseCheckpointSaver(Generic[V]):
         versions to avoid blocking the main thread.
     """
 
-    _get_next_version_legacy: ClassVar[bool] = False
-    """Flag indicating if get_next_version method is legacy (takes two parameters)."""
-
     serde: SerializerProtocol = JsonPlusSerializer()
 
-    def __init_subclass__(cls) -> None:
-        cls._get_next_version_legacy = (
-            len(signature(cls.get_next_version).parameters) > 2  # self + current
-            if hasattr(cls, "get_next_version")
-            else False
-        )
-        return super().__init_subclass__()
-
     def __init__(
         self,
         *,
@@ -138,6 +128,15 @@ class BaseCheckpointSaver(Generic[V]):
     ) -> None:
         self.serde = maybe_add_typed_methods(serde or self.serde)
 
+    @property
+    def config_specs(self) -> list:
+        """Define the configuration options for the checkpoint saver.
+
+        Returns:
+            list: List of configuration field specs.
+        """
+        return []
+
     def get(self, config: RunnableConfig) -> Checkpoint | None:
         """Fetch a checkpoint using the given configuration.
 
@@ -347,7 +346,7 @@ class BaseCheckpointSaver(Generic[V]):
         """
         raise NotImplementedError
 
-    def get_next_version(self, current: V | None) -> V:
+    def get_next_version(self, current: V | None, channel: None) -> V:
         """Generate the next version ID for a channel.
 
         Default is to use integer versions, incrementing by 1. If you override, you can use str/int/float versions,
@@ -355,6 +354,7 @@ class BaseCheckpointSaver(Generic[V]):
 
         Args:
             current: The current version identifier (int, float, or str).
+            channel: Deprecated argument, kept for backwards compatibility.
 
         Returns:
             V: The next version identifier, which must be increasing.
@@ -417,3 +417,54 @@ EXCLUDED_METADATA_KEYS = {
     "checkpoint_ns",
     "checkpoint_map",
 }
+
+# --- below are deprecated utilities used by past versions of LangGraph ---
+
+LATEST_VERSION = 2
+
+
+def empty_checkpoint() -> Checkpoint:
+    from datetime import datetime, timezone
+
+    return Checkpoint(
+        v=LATEST_VERSION,
+        id=str(uuid6(clock_seq=-2)),
+        ts=datetime.now(timezone.utc).isoformat(),
+        channel_values={},
+        channel_versions={},
+        versions_seen={},
+        pending_sends=[],
+    )
+
+
+def create_checkpoint(
+    checkpoint: Checkpoint,
+    channels: Mapping[str, ChannelProtocol] | None,
+    step: int,
+    *,
+    id: str | None = None,
+) -> Checkpoint:
+    """Create a checkpoint for the given channels."""
+    from datetime import datetime, timezone
+
+    ts = datetime.now(timezone.utc).isoformat()
+    if channels is None:
+        values = checkpoint["channel_values"]
+    else:
+        values = {}
+        for k, v in channels.items():
+            if k not in checkpoint["channel_versions"]:
+                continue
+            try:
+                values[k] = v.checkpoint()
+            except EmptyChannelError:
+                pass
+    return Checkpoint(
+        v=LATEST_VERSION,
+        ts=ts,
+        id=id or str(uuid6(clock_seq=step)),
+        channel_values=values,
+        channel_versions=checkpoint["channel_versions"],
+        versions_seen=checkpoint["versions_seen"],
+        pending_sends=checkpoint.get("pending_sends", []),
+    )

libs/checkpoint/langgraph/checkpoint/memory/__init__.py

@@ -512,7 +512,7 @@ class InMemorySaver(
         """
         return self.delete_thread(thread_id)
 
-    def get_next_version(self, current: str | None) -> str:
+    def get_next_version(self, current: str | None, channel: None) -> str:
         if current is None:
             current_v = 0
         elif isinstance(current, int):

libs/checkpoint/tests/checkpoint_utils.py

@@ -1,53 +0,0 @@
-from __future__ import annotations
-
-from collections.abc import Mapping
-from datetime import datetime, timezone
-from typing import Any, Protocol
-
-from langgraph.checkpoint.base import Checkpoint, EmptyChannelError
-from langgraph.checkpoint.base.id import uuid6
-
-
-class ChannelProtocol(Protocol):
-    def checkpoint(self) -> Any | None: ...
-
-
-def empty_checkpoint() -> Checkpoint:
-    return Checkpoint(
-        v=1,
-        id=str(uuid6(clock_seq=-2)),
-        ts=datetime.now(timezone.utc).isoformat(),
-        channel_values={},
-        channel_versions={},
-        versions_seen={},
-    )
-
-
-def create_checkpoint(
-    checkpoint: Checkpoint,
-    channels: Mapping[str, ChannelProtocol] | None,
-    step: int,
-    *,
-    id: str | None = None,
-) -> Checkpoint:
-    """Create a checkpoint for the given channels."""
-    ts = datetime.now(timezone.utc).isoformat()
-    if channels is None:
-        values = checkpoint["channel_values"]
-    else:
-        values = {}
-        for k, v in channels.items():
-            if k not in checkpoint["channel_versions"]:
-                continue
-            try:
-                values[k] = v.checkpoint()
-            except EmptyChannelError:
-                pass
-    return Checkpoint(
-        v=1,
-        ts=ts,
-        id=id or str(uuid6(clock_seq=step)),
-        channel_values=values,
-        channel_versions=checkpoint["channel_versions"],
-        versions_seen=checkpoint["versions_seen"],
-    )

libs/checkpoint/tests/test_memory.py

@@ -6,12 +6,10 @@ from langchain_core.runnables import RunnableConfig
 from langgraph.checkpoint.base import (
     Checkpoint,
     CheckpointMetadata,
-)
-from langgraph.checkpoint.memory import InMemorySaver
-from tests.checkpoint_utils import (
     create_checkpoint,
     empty_checkpoint,
 )
+from langgraph.checkpoint.memory import InMemorySaver
 
 
 class TestMemorySaver:

libs/langgraph/langgraph/pregel/__init__.py

@@ -32,7 +32,6 @@ from langgraph.checkpoint.base import (
     BaseCheckpointSaver,
     Checkpoint,
     CheckpointTuple,
-    copy_checkpoint,
 )
 from langgraph.config import get_config
 from langgraph.constants import (
@@ -79,6 +78,7 @@ from langgraph.pregel.algo import (
 from langgraph.pregel.call import identifier
 from langgraph.pregel.checkpoint import (
     channels_from_checkpoint,
+    copy_checkpoint,
     create_checkpoint,
     empty_checkpoint,
 )

libs/langgraph/langgraph/pregel/algo.py

@@ -83,7 +83,7 @@ from langgraph.types import (
 )
 from langgraph.utils.config import merge_configs, patch_config
 
-GetNextVersion = Callable[[Optional[V]], V]
+GetNextVersion = Callable[[Optional[V], None], V]
 SUPPORTS_EXC_NOTES = sys.version_info >= (3, 11)
 
 
@@ -214,7 +214,7 @@ def local_read(
     return values
 
 
-def increment(current: int | None) -> int:
+def increment(current: int | None, channel: None) -> int:
     """Default channel versioning function, increments the current int version."""
     return current + 1 if current is not None else 1
 
@@ -265,7 +265,8 @@ def apply_writes(
         next_version = get_next_version(
             max(checkpoint["channel_versions"].values())
             if checkpoint["channel_versions"]
-            else None
+            else None,
+            None,
         )
 
     # Consume all channels that were read

libs/langgraph/langgraph/pregel/checkpoint.py

@@ -71,3 +71,14 @@ def channels_from_checkpoint(
         },
         managed_specs,
     )
+
+
+def copy_checkpoint(checkpoint: Checkpoint) -> Checkpoint:
+    return Checkpoint(
+        v=checkpoint["v"],
+        ts=checkpoint["ts"],
+        id=checkpoint["id"],
+        channel_values=checkpoint["channel_values"].copy(),
+        channel_versions=checkpoint["channel_versions"].copy(),
+        versions_seen={k: v.copy() for k, v in checkpoint["versions_seen"].items()},
+    )

libs/langgraph/langgraph/pregel/loop.py

@@ -29,7 +29,6 @@ from typing_extensions import ParamSpec, Self
 
 from langgraph.cache.base import BaseCache
 from langgraph.channels.base import BaseChannel
-from langgraph.channels.last_value import LastValue
 from langgraph.checkpoint.base import (
     EXCLUDED_METADATA_KEYS,
     WRITES_IDX_MAP,
@@ -39,7 +38,6 @@ from langgraph.checkpoint.base import (
     CheckpointMetadata,
     CheckpointTuple,
     PendingWrite,
-    copy_checkpoint,
 )
 from langgraph.constants import (
     CONF,
@@ -86,6 +84,7 @@ from langgraph.pregel.algo import (
 )
 from langgraph.pregel.checkpoint import (
     channels_from_checkpoint,
+    copy_checkpoint,
     create_checkpoint,
     empty_checkpoint,
 )
@@ -963,13 +962,7 @@ class SyncPregelLoop(PregelLoop, AbstractContextManager):
         )
         self.stack = ExitStack()
         if checkpointer:
-            if checkpointer._get_next_version_legacy:
-                empty_channel: LastValue[Any] = LastValue(Any)
-                self.checkpointer_get_next_version = (
-                    lambda c: checkpointer.get_next_version(c, empty_channel)  # type: ignore[call-arg]
-                )
-            else:
-                self.checkpointer_get_next_version = checkpointer.get_next_version
+            self.checkpointer_get_next_version = checkpointer.get_next_version
             self.checkpointer_put_writes = checkpointer.put_writes
             self.checkpointer_put_writes_accepts_task_path = (
                 signature(checkpointer.put_writes).parameters.get("task_path")
@@ -1142,13 +1135,7 @@ class AsyncPregelLoop(PregelLoop, AbstractAsyncContextManager):
         )
         self.stack = AsyncExitStack()
         if checkpointer:
-            if checkpointer._get_next_version_legacy:
-                empty_channel: LastValue[Any] = LastValue(Any)
-                self.checkpointer_get_next_version = (
-                    lambda c: checkpointer.get_next_version(c, empty_channel)  # type: ignore[call-arg]
-                )
-            else:
-                self.checkpointer_get_next_version = checkpointer.get_next_version
+            self.checkpointer_get_next_version = checkpointer.get_next_version
             self.checkpointer_put_writes = checkpointer.aput_writes
             self.checkpointer_put_writes_accepts_task_path = (
                 signature(checkpointer.aput_writes).parameters.get("task_path")

libs/langgraph/tests/test_checkpoint_migration.py

@@ -7,12 +7,9 @@ from typing import Annotated, Literal, Optional, Union
 import pytest
 from typing_extensions import TypedDict
 
-from langgraph.checkpoint.base import (
-    BaseCheckpointSaver,
-    CheckpointTuple,
-    copy_checkpoint,
-)
+from langgraph.checkpoint.base import BaseCheckpointSaver, CheckpointTuple
 from langgraph.graph.state import StateGraph
+from langgraph.pregel.checkpoint import copy_checkpoint
 from langgraph.types import Command, Interrupt, PregelTask, StateSnapshot, interrupt
 from langgraph.utils.config import patch_configurable
 from tests.any_int import AnyInt

libs/langgraph/tests/test_pregel.py

@@ -159,7 +159,7 @@ def test_checkpoint_errors() -> None:
             raise ValueError("Faulty put_writes")
 
     class FaultyVersionCheckpointer(InMemorySaver):
-        def get_next_version(self, current: Optional[int]) -> int:
+        def get_next_version(self, current: Optional[int], channel: None) -> int:
             raise ValueError("Faulty get_next_version")
 
     def logic(inp: str) -> str:

libs/langgraph/tests/test_pregel_async.py

@@ -103,7 +103,7 @@ async def test_checkpoint_errors() -> None:
             raise ValueError("Faulty put_writes")
 
     class FaultyVersionCheckpointer(InMemorySaver):
-        def get_next_version(self, current: Optional[int]) -> int:
+        def get_next_version(self, current: Optional[int], channel: None) -> int:
             raise ValueError("Faulty get_next_version")
 
     def logic(inp: str) -> str:

libs/prebuilt/langgraph/prebuilt/chat_agent_executor.py

@@ -591,7 +591,7 @@ def create_react_agent(
         workflow = StateGraph(state_schema, config_schema=config_schema)
         workflow.add_node(
             "agent",
-            RunnableCallable(call_model, acall_model),  # type: ignore[call-overload]
+            RunnableCallable(call_model, acall_model),
             input_schema=input_schema,
         )
         if pre_model_hook is not None:
@@ -610,7 +610,7 @@ def create_react_agent(
         if response_format is not None:
             workflow.add_node(
                 "generate_structured_response",
-                RunnableCallable(  # type: ignore[call-overload]
+                RunnableCallable(
                     generate_structured_response,
                     agenerate_structured_response,
                 ),
@@ -660,10 +660,10 @@ def create_react_agent(
     # Define the two nodes we will cycle between
     workflow.add_node(
         "agent",
-        RunnableCallable(call_model, acall_model),  # type: ignore[call-overload]
+        RunnableCallable(call_model, acall_model),
         input_schema=input_schema,
     )
-    workflow.add_node("tools", tool_node)  # type: ignore[call-overload]
+    workflow.add_node("tools", tool_node)
 
     # Optionally add a pre-model hook node that will be called
     # every time before the "agent" (LLM-calling node)
@@ -693,7 +693,7 @@ def create_react_agent(
     if response_format is not None:
         workflow.add_node(
             "generate_structured_response",
-            RunnableCallable(  # type: ignore[call-overload]
+            RunnableCallable(
                 generate_structured_response,
                 agenerate_structured_response,
             ),

libs/prebuilt/tests/memory_assert.py

@@ -13,9 +13,9 @@ from langgraph.checkpoint.base import (
     CheckpointMetadata,
     CheckpointTuple,
     SerializerProtocol,
-    copy_checkpoint,
 )
 from langgraph.checkpoint.memory import InMemorySaver, PersistentDict
+from langgraph.pregel.checkpoint import copy_checkpoint
 
 
 class NoopSerializer(SerializerProtocol):