Editing the only turn of a thread reran the original prompt: the model
answered the question the edit was replacing while the UI showed the
edited text, and the edit vanished on reload.
The replay-base lookup decided whether a checkpoint predates the target
user message by message id alone. DynamicContextMiddleware re-keys the
first user turn to `{id}__user` mid-run, so every checkpoint written
before it holds the same prompt under an id the lookup cannot match. The
scan walked past those and anchored inside the run that produced the
turn — a checkpoint that still contains the original prompt and owns the
injection node's pending writes, which the replay then re-added after the
edited message.
Require the replay base to be a settled checkpoint (no pending tasks) in
both the lineage walk and the chronological fallback. That rule is
middleware agnostic: the first turn now anchors on the thread's empty
initial checkpoint and later turns on the previous run's tail, which also
drops the existing reliance on LangGraph discarding a stale `__start__`
write.
Edit replay additionally passes `head_checkpoint` so it resolves its base
lineage-first like regenerate does, and a replayed user message is
restored to its pre-swap id: replaying `{id}__user` into a state that has
no reminder yet makes the middleware treat the turn as already injected
and silently drops its date and memory block.
Frontend: a prepared replay masks the turn it supersedes, so the
optimistic-message baseline is taken from the post-mask human count. The
pre-mask count can never be exceeded when the replay puts exactly one
human message back, and on the first turn the runtime re-keys the
replacement message so identity comparison cannot stand in for the count.
Fixes#4531
Renaming a conversation and then editing one of its turns reverts the
title to whatever it was before that turn ran, so the user's own name for
the thread is silently replaced by an older automatically generated one.
Edit replay resumes from the checkpoint before the edited turn, and that
checkpoint predates the rename. Regenerate already guards against exactly
this rollback by replaying the current title as graph input; the edit
replay path was added later and did not carry the guard over.
Replay the title the same way, but only when the replay base already has
one. An untitled base belongs to a thread the title middleware has not
named yet — pinning the current title there would keep a name generated
from the prompt this edit just replaced, and stop the middleware from
naming the rewritten turn.
* feat(checkpoint): dual-mode checkpoint storage with LangGraph DeltaChannel
Add a restart-required database.checkpoint_channel_mode ("full" default,
"delta") that stores the messages channel via LangGraph 1.2 DeltaChannel,
cutting checkpoint storage from O(n^2) to O(n) for append-only history.
Existing full checkpoints seed delta state transparently; no data migration.
- config: mode schema + freeze-on-first-use with
CheckpointModeReconfigurationError; mode marker persisted in checkpoint
metadata; unsafe delta->full downgrade rejected fail-closed with
CheckpointModeMismatchError (run-level error, failed state read)
- state: delta message state schema; CheckpointStateAccessor centralizes
materialized reads for all consumers (threads API, branches,
regeneration, compaction, state updates, memory, goal workers)
- runtime: raw writers (run durations, interrupted title, thread goal)
parent their checkpoints to the checkpoint they derive from, preserving
delta ancestry; rollback forks the pre-run lineage through a state
mutation graph with Overwrite restores; InMemorySaver delta-history
override delegates to the base walk (fixes dropped first write after
migration, also present upstream)
- tests: conformance suite over {memory, sqlite, postgres} covering
migration replay, stable message IDs, storage shape and writer
preservation; conftest fixture isolates the frozen mode between tests;
stale config fakes refreshed
- ci: backend unit tests gain a postgres service
* fix(checkpoint): close materialization gaps in goal flow, guard public factory
- Route goal-continuation message reads through CheckpointStateAccessor:
raw channel_values reads see the delta sentinel in delta mode, which
disabled goal continuation (stand_down=no_durable_end_of_turn) after
durable assistant turns. Raw tuples remain for tuple-only metadata
(checkpoint id, pending_writes).
- Reject checkpoint_channel_mode='delta' + checkpointer in
create_deerflow_agent at construction: factory-built persisted graphs
bypass mode-marker injection and the fail-closed gate, reproducing
silent mixed-mode state loss. Delta without persistence stays allowed.
- Import the postgres saver lazily (pytest.importorskip in the fixture)
so the documented default install collects the suite; add a CI job
running pytest --collect-only on uv sync --group dev without extras.
- Fix test_checkpointer fallback test to patch get_app_config at its
use site (provider module), making it deterministic when a local
config.yaml selects a persistent backend.
* fix(gateway): preserve extension-owned channels in state mutations, bump config version
- build_state_mutation_graph / build_checkpoint_state_mutation_accessor
accept an explicit state_schema; branch and POST /state now compile the
mutation graph from the thread's effective schema
(graph_state_schema on the assistant graph). The base-ThreadState
fallback silently discarded channels contributed by custom
AgentMiddleware.state_schema on branch (data loss) and returned a
false-success 200 on POST /state.
- POST /state validates values keys against the mutation graph's
channels and rejects unknown fields with 422 instead of ignoring
them; reducer detection covers extension channels
(BinaryOperatorAggregate or DeltaChannel) so Overwrite replace
semantics work for middleware reducers in both modes.
- Endpoint regression: custom AgentMiddleware.state_schema value
survives branch, updates through POST /state, and an unknown field
receives 422.
- config_version 26 -> 27 for the new database.checkpoint_channel_mode
(example, Helm chart values + README, support-bundle fixture), so
existing installs get the outdated-config warning and
make config-upgrade merges the field; covered by a test driving the
real example file and the real config-upgrade script.
* fix(gateway): resolve assistant schema via one boundary, copy branch reducer values with Overwrite
GET /threads/{id}/state now resolves the thread's assistant_id through a
single reusable boundary (thread metadata -> assistant_id -> effective
graph), so channels contributed by a custom AgentMiddleware.state_schema
are materialized instead of dropped by the default lead schema. POST
/state uses the same boundary instead of resolving the schema ad hoc.
Branch writes wrap every copied reducer channel in Overwrite (derived
from the effective mutation graph: BinaryOperatorAggregate + DeltaChannel),
not just messages, so already-aggregated values are never re-merged.
Regression tests use a real AgentMiddleware.state_schema with a
non-identity reducer in both full and delta modes: GET /state returns the
extension value, POST /state replaces it, branch preserves it
byte-for-byte; the unknown-field 422 is a separate assertion.
* refactor(checkpoint): collapse read-path round-trips and ship dual-mode parity tests
Address review round 4 on PR #4292:
- Push ahistory/history limit through Pregel into checkpointer.alist
(SQL LIMIT) instead of materializing all rows and breaking in Python
- Fold the read-side mode-compat gate onto the returned snapshot's
metadata; only writes keep the pre-write tuple fetch (fail-closed)
- Cache factory-built accessor graphs per (assistant_id, mode) with
factory-identity revalidation; state reads no longer build a lead
agent per request
- get_thread: one snapshot fetch + one raw pending_writes fetch on the
resolved checkpoint (post-checkpoint __error__ writes never surface
in snapshot.tasks; verified empirically)
- DeerFlowClient.get_thread: single checkpointer.list walk collects
pending_writes per checkpoint instead of N get_tuple calls
- InMemorySaver delta-history patch: stand-down when the upstream
override disappears, try/except guard, validated-version warning,
guard tests
- make_lead_agent mode precedence: first freeze is owned by app_config
(client-supplied configurable key ignored); once frozen, injected
key/app_config must match or fail closed
- Rollback: lock in non-message channel restoration via fork
inheritance with a dedicated reducer-channel test
- Add tests/test_threads_checkpoint_mode.py and
tests/test_gateway_checkpoint_mode.py referenced by AGENTS.md and
the PR validation section: lifecycle parity (memory + sqlite),
per-step blob-count storage guard, gateway endpoint parity
Counted-saver tests pin checkpoint round-trips for aget/ahistory so
these regressions cannot silently return.
* fix(checkpoint): precise mode-mismatch HTTP mapping, gate E2E, and accessor resilience
- threads router: map CheckpointModeMismatchError to 409 (with cause and
thread id) and CheckpointModeReconfigurationError to 503 across all state
endpoints instead of swallowing both into a generic 500
- gate coverage: seed a real delta checkpoint into AsyncSqliteSaver and
assert aget/aupdate/ahistory fail closed; assert 409 at the HTTP boundary
through the real route stack
- rollback: compile the restore mutation graph with the thread's effective
state schema per the build_state_mutation_graph contract
- inheritance contract locks: rollback and manual compaction preserve
middleware-contributed channels via checkpoint fork cloning
- services: revalidate the accessor-graph cache against app_config identity
so config.yaml hot-reloads never serve a stale compiled graph
- services: degrade full-mode state reads to raw checkpointer reads when the
agent factory is unavailable (delta gate still applies; delta mode has no
fallback)
- deps: override websockets==16.0 (langgraph-sdk 0.4.2's <16 pin silently
downgraded 16.0 -> 15.0.1; pin is not grounded in any API incompatibility)
and bump the langchain lower bound to what the lockfile actually resolves
* fix(checkpoint): include anchor checkpoint in degraded history walk + cover get_thread
- _RawCheckpointReadAccessor.ahistory: alist(before=...) is exclusive while
pregel's get_state_history treats config.checkpoint_id as the inclusive
start; fetch the anchor explicitly so both read paths paginate identically
- extend the degraded-path gateway test: GET /thread returns raw values, and
POST /history with before starts at the anchor checkpoint
* fix(gateway): preserve degraded checkpoint timestamps
* fix(gateway): harden degraded checkpoint access
* fix(gateway): resolve assistants for checkpoint reads
---------
Co-authored-by: Willem Jiang <willem.jiang@gmail.com>
* fix: persist run duration in checkpoints for history reads
* fix(checkpoint): harden run duration persistence
* fix(checkpoint): persist run durations in metadata
* fix(checkpoint): address review findings for run duration persistence
- Add valid_duration_entry() shared validation helper (worker.py)
- Rename _persist_run_durations -> persist_run_durations as public API
- Import public persist_run_durations and valid_duration_entry in threads.py
- Use BackgroundTasks for lazy backfill write to avoid blocking history reads
- Add TODO about O(runs) growth of run_durations in checkpoint metadata
- Document REGENERATE_HISTORY_RAW_SCAN_LIMIT doubling assumption
* fix(checkpoint): replace pruning TODO with justification
Accumulated run_durations overhead (~50 bytes/run_id) is negligible compared
to messages channel blobs; no pruning strategy is needed.
---------
Co-authored-by: Willem Jiang <willem.jiang@gmail.com>
