Fixes langchain-ai/langgraph#8382
`DeltaChannel` rebuilds its value by replaying ancestor writes through
the reducer. Every saver ordered a checkpoint's writes by `(task_id,
idx)`, but live execution applies a super-step's writes in task-path
order (`apply_writes` sorts tasks by `task_path_str(task.path[:3])`).
`task_id` is a hash of the path, so when two or more tasks write one
`DeltaChannel` in the same super-step, replay applies them in an
arbitrary permutation.
Reducers must be batching-invariant, not order-invariant, so the
permutation changes the value: `get_state` disagrees with what `invoke`
returned, and continuing the thread saves the reordered value as the
base for every later write.
## Fix
Replay orders by `(task_path, task_id, idx)`, the order
`SELECT_PENDING_SENDS_SQL` already uses for sends. `apply_writes` and
every saver now sort with one `writes_sort_key` from
`langgraph.checkpoint.base`, in Python, so live and replay can't drift
apart and don't depend on a database collation. `apply_writes` sorts by
the full task path, the string `put_writes` stores, instead of
`path[:3]`. The paths that reach `apply_writes` no longer carry task
ids, so the live order doesn't change.
`BaseCheckpointSaver`'s default `get_delta_channel_history` can't sort
by path, since `PendingWrite` has no task path, so it replays each
checkpoint's writes in `get_tuple` order. `get_tuple` now has to return
`pending_writes` in `writes_sort_key` order, and memory, SQLite and
Postgres do, so the default walk is right for any saver that follows
that. `AsyncPostgresSaver` also gets the sync
`get_delta_channel_history` that `AsyncSqliteSaver` already had; sync
reads used to fall back to the default walk.
Memory and Postgres already stored `task_path`. SQLite accepted it on
`put_writes` and dropped it, so `writes` gains the column and `setup()`
adds it to existing databases.
Writes without a task path (graph input, `update_state` updates, rows
written before the column existed) sort first by `task_id`, which is
also where live execution applies input.
## Compatibility
- Memory and Postgres already had `task_path` on disk, so existing
threads replay in the corrected order after upgrade.
- On SQLite, rows from before the upgrade read back as `''` and keep
their old order. Only new writes get the corrected order, since there is
no stored path to recover.
- SQLite has no `ADD COLUMN IF NOT EXISTS`, so `setup()` runs the
`ALTER` and treats `duplicate column name` as success, which also covers
two processes migrating one file. That error comes while SQLite prepares
the statement, before it asks for the write lock, so `setup()` on an
up-to-date database doesn't wait on other writers. A read-only database
from before the column is read with empty paths instead of failing
setup.
- Downgrade is safe: older code's `INSERT` omits the column and the
column has a default.
- `get_tuple` and `list` return `pending_writes` in `writes_sort_key`
order instead of task id order (SQLite, Postgres) or put order (memory).
Nothing in langgraph depends on the old order.
- Postgres reads `task_path` and `idx` with each pending write, so a
subclass that pairs `SELECT_SQL` with its own `_load_writes`, or the
other way round, has to match the new row shape.
- A third-party saver has to replay in `writes_sort_key` order: in its
own `get_delta_channel_history` if it has one, otherwise by returning
`pending_writes` from `get_tuple` in that order. Otherwise it fails the
new conformance tests; the `get_tuple` one is a base test, so it runs
for every saver.
- langgraph, checkpoint-sqlite and checkpoint-postgres import
`writes_sort_key` from langgraph-checkpoint, so this bumps
langgraph-checkpoint to 4.3.0 and requires it there. 4.3.0 has to be
released first.
## Limits
- Several updates in one `bulk_update_state` super-step share a task id,
so the saver keeps only the first one's writes and the `DeltaChannel`
loses the rest (plain channels are fine). That's on main too; #9128
fixes it and stores a task path per update, so with this PR those
updates also replay in the order given.
- Exit durability stores its writes differently; resume ordering there
is fixed in #9114, stacked on this PR.
- langgraphjs applies `DeltaChannel` writes in task id order, live and
on replay (langchain-ai/langgraphjs#2544), so its reads match too.
Moving JS to task path order is a follow-up.
## Tests
Each fails on main and passes here:
- `test_delta_channel_parallel_order.py`, across memory, SQLite and
Postgres: parallel writers and a `Send` fan-out, comparing `get_state`
with the live result, including sync `get_state` on the async savers.
- Three conformance tests whose task ids sort opposite to their task
paths, so they cannot pass by chance: two on
`get_delta_channel_history`, one on `get_tuple`'s `pending_writes`
order.
- SQLite migration tests from a pre-column database, sync and async,
including a read-only file.
One more that passes on main too: SQLite `setup()` while another
connection holds the write lock, with no busy timeout, sync and async.
It keeps the `ALTER` from waiting on that lock.
Thanks to @ErenAta16 for the report, the reproduction, and for tracing
`task_path` through all three backends, and to @ragnarok268 for the
conformance-test design with task ids ordered opposite to their paths.
---------
Co-authored-by: ErenAta16 <149434812+ErenAta16@users.noreply.github.com>
Co-authored-by: ragnarok268 <58264829+ragnarok268@users.noreply.github.com>
Version bump only. No library code changes in this PR.
Unreleased since `checkpoint==4.1.1`:
- #8526 - collect writes at plain-value seed in delta channel history
- #8354 - add opt-in `TTLConfig.omit_expired` to skip expired rows on
read
Minor rather than patch because #8354 adds a new public `TTLConfig` key.
Note that the checkpoint-postgres half of #8354 already shipped in
`checkpointpostgres==3.1.1`, so the currently released Postgres saver
honors an option that no released `langgraph-checkpoint` declares. This
closes that gap.
`langgraph-checkpoint-postgres` 3.1.2 (#8535) follows once this is live
on PyPI.
Follow-up to #8540, which turned on `PLC0415` (import-outside-top-level)
for checkpoint-postgres and checkpoint-sqlite. This does the remaining
six packages: checkpoint, checkpoint-conformance, langgraph, prebuilt,
cli, sdk-py.
Scoped to tests, per @sydney-runkle's call on #8540: library code is
exempted with `per-file-ignores`, since it still has deferred imports
nobody has reviewed and mixing that in would make this hard to read.
## What changed
Function-level imports across 56 test files moved to module level. Nine
could not move and carry an explicit `# noqa: PLC0415` with a reason:
| File | Why it stays local |
|---|---|
| `libs/langgraph/tests/test_deprecation.py` (4) | the import has to run
inside `pytest.warns` for the warning to be observed |
| `libs/langgraph/tests/test_serde_allowlist.py` | try/except guard,
skips when langchain_core is absent |
| `libs/langgraph/tests/test_delta_channel_benchmark.py` | optional
psycopg probe |
| `libs/checkpoint/tests/test_conformance_delta.py` (3) | protected by a
module-level `pytest.importorskip`; hoisting past the guard turns a skip
into a collection error |
That last one is the trap: an import moved above `pytest.importorskip`
silently defeats the guard. I hit it locally and it turned the skip into
a `ModuleNotFoundError` at collection. Every file with an `importorskip`
or `except ImportError` was checked by hand for this.
## Verification
`make lint` and `make test` in each of the six:
| Package | Tests |
|---|---|
| checkpoint | 156 passed, 17 skipped |
| checkpoint-conformance | 1 passed |
| langgraph | 1968 passed, 4 skipped |
| prebuilt | 284 passed |
| cli | 336 passed |
| sdk-py | 493 passed |
Also confirmed the rule actually fires: a throwaway test file with a
function-level import is flagged in all six packages, and the source
exemption holds.
Follow-up to review on #8540, where a stale `# noqa: E402` slipped past
me and Sydney spotted it by eye. This turns on the rule that catches
that automatically.
`RUF100` flags a `noqa` that suppresses nothing. `sdk-py` already had it
through its blanket `RUF` selection; this adds it to the other seven
packages and clears what it finds.
### The 33 it flags, all autofixed
**Blanket `# noqa` on docstring-closing lines** (4, in
`checkpoint-postgres` and `checkpoint-sqlite`). `E501` is in
`lint.ignore` for those packages, so nothing was being suppressed:
```diff
- """ # noqa
+ """
```
**`# noqa: F821` on `anext(aiter_)`** (2). Left over from Python 3.9
support. `anext` became a builtin in 3.10, which is the floor now, so
`F821` no longer fires:
```diff
- anext(aiter_), # type: ignore[arg-type] # noqa: F821
+ anext(aiter_), # type: ignore[arg-type]
```
**Suppressions naming rules the package does not enable** (27), across
`langgraph`, `prebuilt` and `checkpoint-sqlite`: `FBT001`, `FBT002`,
`TC002`, `BLE001`, `ANN001`, `ANN002`, `ANN003`, `E501`, `F401`. Mostly
copied between packages whose rule sets differ.
### One measurement note
If you check these numbers yourself, use `--extend-select`:
```
ruff check --select RUF100 . # 81, misleading
ruff check --extend-select RUF100 . # 33, real
```
With a bare `--select`, ruff treats every other rule as disabled, so
every suppression for another rule looks unused. I quoted 81 before
catching that.
### Verified
`checkpoint-sqlite` 118 passed, `prebuilt` 284 passed, `langgraph` 1968
passed, `checkpoint-postgres` 264 passed on PG 15 and 16. `make lint`
clean in every package.
Independent of #8540 and #8537, so it can land in any order.
## Summary
- replace Python lint type-checking from mypy to ty across LangGraph
packages
- remove mypy config/cache wiring and mypy-only references
- regenerate uv locks with ty 0.0.43
## Verification
- git diff --check
- make lint_package && make lint_tests in libs/langgraph
- make lint_package && make lint_tests in libs/checkpoint
- make lint_package && make lint_tests in libs/checkpoint-sqlite
- make lint_package && make lint_tests in libs/checkpoint-postgres
- make lint_package && make lint_tests in libs/prebuilt
- make lint_package && make lint_tests in libs/cli
- make lint in libs/sdk-py
- make lint in libs/checkpoint-conformance
---------
Co-authored-by: Claude <noreply@anthropic.com>
Co-authored-by: open-swe[bot] <215916821+open-swe[bot]@users.noreply.github.com>
## Summary
Bumps all alpha-versioned packages to their official releases:
- `langgraph`: `1.2.0a7` → `1.2.0`
- `langgraph-checkpoint`: `4.1.0a4` → `4.1.0`
- `langgraph-checkpoint-postgres`: `3.1.0a4` → `3.1.0`
- `langgraph-checkpoint-sqlite`: `3.1.0a1` → `3.1.0`
- `langgraph-prebuilt`: `1.1.0a2` → `1.1.0`
Also removes the `a*` alpha specifiers from cross-dependency pins in
`langgraph`, `checkpoint-postgres`, and `checkpoint-sqlite`, and
regenerates all `uv.lock` files.
## Summary
- Bumps `langgraph` 1.2.0a1 → 1.2.0a3
- Bumps `langgraph-checkpoint` 4.1.0a1 → 4.1.0a3
- Bumps `langgraph-checkpoint-postgres` 3.1.0a1 → 3.1.0a3
- Bumps min `langgraph-checkpoint` constraint in `langgraph` to
`>=4.1.0a3`
- Refreshes uv locks across the workspace
(Note: `a2` was already cut from another branch.)
## Test plan
- [ ] CI passes
## Description
Updates the X/Twitter social links to point to the new `@langchain_oss`
account across README badges and Python package metadata.
## Test Plan
- [ ] Verify README badges and package metadata point to
`@langchain_oss` on X
_Opened collaboratively by Mason Daugherty and open-swe._
---------
Co-authored-by: open-swe[bot] <open-swe@users.noreply.github.com>
Co-authored-by: Mason Daugherty <61371264+mdrxy@users.noreply.github.com>
Co-authored-by: Mason Daugherty <mason@langchain.dev>
In this PR:
- Bump `langgraph-checkpoint` to 3.0
- Bump `langgraph-checkpoint-sqlite` to 3.0; Update
`langgraph-checkpoint` deps to >=3,<4
- Bump `langgraph-checkpoint-postgres` to 3.0; Update
`langgraph-checkpoint` max to <4 (keep prior min since the deprecated
functionality wasn't explicitly used)
- Bump `langgraph` to 1.0.1; update `langgraph-checkpoint` max bound to
4
- Bump `prebuilt` to 1.0.1; update `langgraph-checkpoint` max bound to 4
* catching error thrown by asyncio
* using 2nd check for annotations given Pydantic 2.12 changes
* skipping tests for remote graph bc langgraph-api is dependent on
`jsonschema-rs`
* skipping tests w/ pydantic v1 models
```bash
hint: This usually indicates a problem with the package or the build environment.
help: `jsonschema-rs` (v0.29.1) was included because `langgraph:dev` (v1.0.0rc1) depends on `langgraph-cli[inmem]` which
depends on `langgraph-api` (v0.4.29) which depends on `jsonschema-rs`
```
not yet testing for free threaded python, that'll be much more involved!
ended up separating lint / testing deps during this process bc I was
getting a ton of not required deps while testing that were complicating
things :/
### Description
Adds Redis as a supported cache backend for LangGraph node-level
caching, enabling distributed caching across multiple processes/servers.
This implementation follows the same patterns as existing InMemoryCache
and SqliteCache.
### Key changes
- New RedisCache class implementing the BaseCache interface
- Support for TTL-based expiration and batch operations
- Worker-specific cache prefixes for parallel test isolation
### Dependencies
- redis package (already included in dev dependencies)
### Test Plan
- Unit tests: Added Redis cache tests covering basic operations, TTL,
batch operations, and error handling
- Integration tests: Redis cache integrated into existing LangGraph test
suite, tested with all checkpointer combinations
* Migrate to `uv`
* Format `pyproject.toml` files properly
* Remove upper bounds on dependencies, and bounds on dev dependencies
(we should be using latest)
* Move to hatch for packaing
In the future we should:
* Set up dependabot / automate lockfile updates and tests
* Add tests for min compatible versions (I'll do this right after merge)
* Use dynamic versioning
* Bump `pydantic` to v2.11.4 in the lockfile, we have some tests failing
A few notes:
* We shouldn't be using `tool.poetry.dependencies`, that's deprecated -
waiting for a future PR to address this big change though.
* We should remove upper bounds for all deps unless strictly necessary.
