fix: AsyncRedisSaver cannot be constructed outside an async context (…

[bsbodden]

…#179)

[Copilot]

Pull request overview

Addresses Issue #179 by allowing Redis async checkpoint savers to be instantiated in synchronous code (no running event loop) and deferring event-loop capture until async setup.

Changes:

• Defer loop initialization in AsyncRedisSaver / AsyncShallowRedisSaver from __init__ to asetup().
• Add explicit runtime errors when synchronous wrapper methods are called before asetup() / async with.
• Add regression tests covering construction outside an event loop and loop capture during asetup().

Reviewed changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 5 comments.

File	Description
langgraph/checkpoint/redis/aio.py	Defers loop capture to asetup() and adds “must be set up” guards for sync wrappers.
langgraph/checkpoint/redis/ashallow.py	Same as above for shallow saver; adds “must be set up” guards for sync wrappers.
tests/test_async.py	Adds regression tests for AsyncRedisSaver construction outside a running loop and loop capture in asetup() / context manager.
tests/test_shallow_async.py	Adds analogous regression tests for AsyncShallowRedisSaver.

Comments suppressed due to low confidence (1)

langgraph/checkpoint/redis/aio.py:1343

• The InvalidStateError guidance here points users to await checkpointer.get_channel_values(...), but that is the synchronous method name. This message should refer to the async API (e.g., await checkpointer.aget_channel_values(...)) to avoid confusing users who hit this error.

                raise asyncio.InvalidStateError(
                    "Synchronous calls to AsyncRedisSaver are only allowed from a "
                    "different thread. From the main thread, use the async interface."
                    "For example, use `await checkpointer.get_channel_values(...)`."
                )

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[bsbodden]

Also addressed the suppressed low-confidence comment about the wrong method name in the get_channel_values() error message (aio.py:1343): the guidance string previously said await checkpointer.get_channel_values(...) (the sync name) — now correctly reads await checkpointer.aget_channel_values(...).

[Copilot]

Pull request overview

Copilot reviewed 4 out of 4 changed files in this pull request and generated 2 comments.

Comments suppressed due to low confidence (2)

langgraph/checkpoint/redis/ashallow.py:827

• The InvalidStateError message is constructed from adjacent string literals and is missing a space after "use the async interface.", producing "interface.For example" at runtime. Add a space or merge the literals.

                raise asyncio.InvalidStateError(
                    "Synchronous calls to AsyncShallowRedisSaver are only allowed from a "
                    "different thread. From the main thread, use the async interface."
                    "For example, use `await checkpointer.aget_channel_values(...)`."
                )

langgraph/checkpoint/redis/ashallow.py:748

• This InvalidStateError message is split across string literals without a space after "use the async interface.", so it will display as "interface.For example". Add a trailing space to the first literal or combine them.

                raise asyncio.InvalidStateError(
                    "Synchronous calls to AsyncShallowRedisSaver are only allowed from a "
                    "different thread. From the main thread, use the async interface."
                    "For example, use `await checkpointer.aget_tuple(...)` or `await "
                    "graph.ainvoke(...)`."

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[bsbodden]

@copilot apply changes based on the comments in this thread