chore(deps): Bump langgraph from 1.0.3 to 1.2.0 in /a2a/image_service

[dependabot]

Bumps langgraph from 1.0.3 to 1.2.0.

Release notes

Sourced from langgraph's releases.

langgraph==1.2.0

Changes since 1.2.0a7

• release: bump alpha packages to official versions (#7775)
• feat(langgraph): durable error-handler resume across host crashes (#7773)
• feat(langgraph): add set_node_defaults() to StateGraph (#7747)
• chore(deps): bump urllib3 from 2.6.3 to 2.7.0 in /libs/langgraph (#7766)
• chore(deps): bump mistune from 3.2.0 to 3.2.1 in /libs/langgraph (#7733)
• chore(langgraph): bump langchain-core to 1.4.0 (#7767)
• feat(checkpoint): force delta channel snapshot after max supersteps since last snapshot (#7746)
• test(langgraph): de-flake heartbeat progress test (#7735)
• chore(langgraph): re-implement exit mode for delta channel (#7730)
• chore(deps): bump ty from 0.0.23 to 0.0.33 in /libs/sdk-py (#7666)
• docs(checkpoint): mark DeltaChannel and delta-history APIs as beta (#7732)
• chore(deps): bump jupyter-server from 2.17.0 to 2.18.0 in /libs/langgraph (#7713)
• feat(checkpoint-sqlite): override get_delta_channel_history with streaming walk (#7702)
• chore: "chore: minor clean up around checkpoint and delta channel" (#7706)
• chore: minor clean up around checkpoint and delta channel (#7705)

langgraph==1.2.0a7

Changes since 1.2.0a6

• release: alpha bump (a4) for langgraph, checkpoint, checkpoint-postgres (#7701)
• feat: public get_writes_history saver API + delta cadence rework (#7699)

langgraph==1.2.0a6

langgraph v1.2 (alpha)

This release adds finer-grained control over node execution — timeouts, error recovery, and graceful shutdown — a new channel type that cuts checkpoint overhead for long-running threads, and a new content-block-centric streaming API (v3) with typed, per-channel projections.

---

DeltaChannel (beta)

A new channel type that stores only the incremental delta at each step rather than re-serializing the full accumulated value. Most useful for channels that grow large over time — for example, a message list in a long-running thread. Without it, the full message list is written into every checkpoint; with DeltaChannel, only the new messages from each step are stored.

Use snapshot_frequency=K to write a full snapshot every K steps and bound read latency:

from typing import Annotated, Sequence
from typing_extensions import TypedDict
from langgraph.channels import DeltaChannel
batch reducer: receives the current value and all writes from the superstep at once
def list_reducer(messages: list[str], writes: Sequence[list[str]]) -> list[str]:
return [*messages, *(item for write in writes for item in write)]
class State(TypedDict):
messages: Annotated[list[str], DeltaChannel(list_reducer, snapshot_frequency=5)]

... (truncated)

Commits

• 3614e88 release: bump alpha packages to official versions (#7775)
• 6dff3b3 feat(langgraph): durable error-handler resume across host crashes (#7773)
• 786c42f release(cli): 0.4.26 (#7772)
• 8537ea9 fix(cli): add support for prerelease api_versions (#7771)
• 3db82d5 feat(langgraph): add set_node_defaults() to StateGraph (#7747)
• 029eabf chore(deps): bump urllib3 from 2.6.3 to 2.7.0 in /libs/checkpoint (#7762)
• f52f1ce chore(deps): bump the uv group across 2 directories with 1 update (#7749)
• e47a7bb chore(deps): bump langchain-core from 1.3.2 to 1.3.3 in /libs/checkpoint (#7752)
• 29fefa0 chore(deps): bump urllib3 from 2.6.3 to 2.7.0 in /libs/langgraph (#7766)
• 0c23779 chore(deps): bump urllib3 from 2.6.3 to 2.7.0 in /libs/cli (#7765)
• Additional commits viewable in compare view