@langchain/langgraph/dist/pregel/algo.cjs.map

LangGraph

{"version":3,"file":"algo.cjs","names":["getNullChannelVersion","TAG_HIDDEN","isDeltaChannel","createCheckpoint","emptyChannels","readChannels","_isSend","InvalidUpdateError","NO_WRITES","PUSH","RESUME","INTERRUPT","RETURN","ERROR","ERROR_SOURCE_NODE","RESERVED","getOnlyChannels","TASKS","PULL","isCall","getRunnableForFunc","CONFIG_KEY_TASK_ID","CONFIG_KEY_SEND","CONFIG_KEY_READ","CONFIG_KEY_CHECKPOINTER","CONFIG_KEY_CHECKPOINT_MAP","CONFIG_KEY_SCRATCHPAD","CONFIG_KEY_RESUME_MAP","XXH3","CONFIG_KEY_PREVIOUS_STATE","PREVIOUS","CACHE_NS_WRITES","_isSendInterface","Send","CONFIG_KEY_NODE_ERROR","NodeError","readChannel","EmptyChannelError"],"sources":["../../src/pregel/algo.ts"],"sourcesContent":["/* eslint-disable no-param-reassign */\nimport {\n  mergeConfigs,\n  patchConfig,\n  RunnableConfig,\n} from \"@langchain/core/runnables\";\nimport { CallbackManagerForChainRun } from \"@langchain/core/callbacks/manager\";\nimport {\n  All,\n  BaseCheckpointSaver,\n  Checkpoint,\n  ReadonlyCheckpoint,\n  copyCheckpoint,\n  type PendingWrite,\n  type PendingWriteValue,\n  uuid5,\n  maxChannelVersion,\n  BaseStore,\n  CheckpointPendingWrite,\n  SendProtocol,\n} from \"@langchain/langgraph-checkpoint\";\nimport {\n  BaseChannel,\n  createCheckpoint,\n  emptyChannels,\n  isDeltaChannel,\n  getOnlyChannels,\n} from \"../channels/base.js\";\nimport { PregelNode } from \"./read.js\";\nimport { readChannel, readChannels } from \"./io.js\";\nimport {\n  _isSend,\n  _isSendInterface,\n  CONFIG_KEY_CHECKPOINT_MAP,\n  CHECKPOINT_NAMESPACE_SEPARATOR,\n  CONFIG_KEY_CHECKPOINTER,\n  CONFIG_KEY_READ,\n  CONFIG_KEY_TASK_ID,\n  CONFIG_KEY_SEND,\n  INTERRUPT,\n  RESERVED,\n  Send,\n  TAG_HIDDEN,\n  TASKS,\n  CHECKPOINT_NAMESPACE_END,\n  PUSH,\n  PULL,\n  RESUME,\n  NULL_TASK_ID,\n  CONFIG_KEY_SCRATCHPAD,\n  RETURN,\n  ERROR,\n  ERROR_SOURCE_NODE,\n  NO_WRITES,\n  CONFIG_KEY_PREVIOUS_STATE,\n  PREVIOUS,\n  CACHE_NS_WRITES,\n  CONFIG_KEY_RESUME_MAP,\n  CONFIG_KEY_NODE_ERROR,\n  START,\n} from \"../constants.js\";\nimport {\n  Call,\n  isCall,\n  PregelExecutableTask,\n  PregelScratchpad,\n  PregelTaskDescription,\n  SimpleTaskPath,\n  TaskPath,\n  VariadicTaskPath,\n} from \"./types.js\";\nimport { EmptyChannelError, InvalidUpdateError, NodeError } from \"../errors.js\";\nimport { getNullChannelVersion } from \"./utils/index.js\";\nimport { ExecutionInfo, LangGraphRunnableConfig } from \"./runnable_types.js\";\nimport { getRunnableForFunc } from \"./call.js\";\nimport { IterableReadableWritableStream } from \"./stream.js\";\nimport { XXH3 } from \"../hash.js\";\nimport { Topic } from \"../channels/topic.js\";\n\n/**\n * Construct a type with a set of properties K of type T\n */\nexport type StrRecord<K extends string, T> = {\n  [P in K]: T;\n};\n\nexport type WritesProtocol<C = string> = {\n  name: string;\n  writes: PendingWrite<C>[];\n  triggers: string[];\n  path?: TaskPath;\n};\n\nexport const increment = (current?: number) => {\n  return current !== undefined ? current + 1 : 1;\n};\n\nfunction triggersNextStep(\n  updatedChannels: Set<string>,\n  triggerToNodes: Record<string, string[]> | undefined\n) {\n  if (triggerToNodes == null) return false;\n\n  for (const chan of updatedChannels) {\n    if (triggerToNodes[chan]) return true;\n  }\n\n  return false;\n}\n\n// Avoids unnecessary double iteration\nfunction maxChannelMapVersion(\n  channelVersions: Record<string, number | string>\n): number | string | undefined {\n  let maxVersion: number | string | undefined;\n  for (const chan in channelVersions) {\n    if (!Object.prototype.hasOwnProperty.call(channelVersions, chan)) continue;\n    if (maxVersion == null) {\n      maxVersion = channelVersions[chan];\n    } else {\n      maxVersion = maxChannelVersion(maxVersion, channelVersions[chan]);\n    }\n  }\n  return maxVersion;\n}\n\nexport function shouldInterrupt<N extends PropertyKey, C extends PropertyKey>(\n  checkpoint: Checkpoint,\n  interruptNodes: All | N[],\n  tasks: PregelExecutableTask<N, C>[]\n): boolean {\n  const nullVersion = getNullChannelVersion(checkpoint.channel_versions);\n  const seen = checkpoint.versions_seen[INTERRUPT] ?? {};\n\n  let anyChannelUpdated = false;\n\n  if (\n    (checkpoint.channel_versions[START] ?? nullVersion) >\n    (seen[START] ?? nullVersion)\n  ) {\n    anyChannelUpdated = true;\n  } else {\n    for (const chan in checkpoint.channel_versions) {\n      if (\n        !Object.prototype.hasOwnProperty.call(checkpoint.channel_versions, chan)\n      )\n        continue;\n\n      if (checkpoint.channel_versions[chan] > (seen[chan] ?? nullVersion)) {\n        anyChannelUpdated = true;\n        break;\n      }\n    }\n  }\n\n  const anyTriggeredNodeInInterruptNodes = tasks.some((task) =>\n    interruptNodes === \"*\"\n      ? !task.config?.tags?.includes(TAG_HIDDEN)\n      : interruptNodes.includes(task.name)\n  );\n\n  return anyChannelUpdated && anyTriggeredNodeInInterruptNodes;\n}\n\nexport function _localRead<Cc extends Record<string, BaseChannel>>(\n  checkpoint: ReadonlyCheckpoint,\n  channels: Cc,\n  task: WritesProtocol<keyof Cc>,\n  select: Array<keyof Cc> | keyof Cc,\n  fresh: boolean = false\n): Record<string, unknown> | unknown {\n  let updated = new Set<keyof Cc>();\n\n  if (!Array.isArray(select)) {\n    for (const [c] of task.writes) {\n      if (c === select) {\n        updated = new Set([c]);\n        break;\n      }\n    }\n    updated = updated || new Set();\n  } else {\n    updated = new Set(\n      select.filter((c) => task.writes.some(([key, _]) => key === c))\n    );\n  }\n\n  let values: Record<string, unknown>;\n\n  if (fresh && updated.size > 0) {\n    const localChannels = Object.fromEntries(\n      Object.entries(channels).filter(([k, _]) => updated.has(k as keyof Cc))\n    ) as Partial<Cc>;\n\n    // DeltaChannels are omitted from `channel_values` by default (their state\n    // is reconstructed from ancestor writes via the saver). A local read has\n    // no saver, so snapshot every delta channel inline to round-trip its full\n    // live value through `emptyChannels`.\n    const channelsToSnapshot = new Set<string>();\n    for (const k in localChannels) {\n      if (!Object.prototype.hasOwnProperty.call(localChannels, k)) continue;\n      const ch = (localChannels as Record<string, BaseChannel>)[k];\n      if (isDeltaChannel(ch) && ch.isAvailable()) channelsToSnapshot.add(k);\n    }\n\n    const newCheckpoint = createCheckpoint(\n      checkpoint,\n      localChannels as Cc,\n      -1,\n      {\n        channelsToSnapshot,\n      }\n    );\n    const newChannels = emptyChannels(localChannels as Cc, newCheckpoint);\n\n    _applyWrites(\n      copyCheckpoint(newCheckpoint),\n      newChannels,\n      [task],\n      undefined,\n      undefined\n    );\n    values = readChannels({ ...channels, ...newChannels }, select);\n  } else {\n    values = readChannels(channels, select);\n  }\n\n  return values;\n}\n\nexport function _localWrite(\n  // eslint-disable-next-line @typescript-eslint/no-explicit-any\n  commit: (writes: [string, any][]) => any,\n  processes: Record<string, PregelNode>,\n  // eslint-disable-next-line @typescript-eslint/no-explicit-any\n  writes: [string, any][]\n) {\n  for (const [chan, value] of writes) {\n    if ([PUSH, TASKS].includes(chan) && value != null) {\n      if (!_isSend(value)) {\n        throw new InvalidUpdateError(\n          `Invalid packet type, expected SendProtocol, got ${JSON.stringify(\n            value\n          )}`\n        );\n      }\n      if (!(value.node in processes)) {\n        throw new InvalidUpdateError(\n          `Invalid node name \"${value.node}\" in Send packet`\n        );\n      }\n    }\n  }\n  commit(writes);\n}\n\nconst IGNORE = new Set<string | number | symbol>([\n  NO_WRITES,\n  PUSH,\n  RESUME,\n  INTERRUPT,\n  RETURN,\n  ERROR,\n  ERROR_SOURCE_NODE,\n]);\n\nconst RESERVED_SET: ReadonlySet<string> = new Set(RESERVED);\n\nexport function _applyWrites<Cc extends Record<string, BaseChannel>>(\n  checkpoint: Checkpoint,\n  channels: Cc,\n  tasks: WritesProtocol<keyof Cc>[],\n  // eslint-disable-next-line @typescript-eslint/no-explicit-any\n  getNextVersion: ((version: any) => any) | undefined,\n  triggerToNodes: Record<string, string[]> | undefined\n): Set<string> {\n  // Pre-compute paths once before sorting to avoid repeated .slice() allocations\n  // eslint-disable-next-line @typescript-eslint/no-explicit-any\n  const pathCache = new Map<WritesProtocol<keyof Cc>, any[]>();\n  for (const task of tasks) {\n    pathCache.set(task, task.path?.slice(0, 3) || []);\n  }\n\n  // Sort tasks by first 3 path elements for deterministic order\n  // Later path parts (like task IDs) are ignored for sorting\n  tasks.sort((a, b) => {\n    const aPath = pathCache.get(a)!;\n    const bPath = pathCache.get(b)!;\n\n    // Compare each path element\n    for (let i = 0; i < Math.min(aPath.length, bPath.length); i += 1) {\n      if (aPath[i] < bPath[i]) return -1;\n      if (aPath[i] > bPath[i]) return 1;\n    }\n\n    // If one path is shorter, it comes first\n    return aPath.length - bPath.length;\n  });\n\n  // Filter out non instances of BaseChannel\n  const onlyChannels = getOnlyChannels(channels);\n\n  // Single pass: update seen versions, check for triggers, collect channels to consume\n  let bumpStep = false;\n  const channelsToConsume = new Set<string>();\n  for (const task of tasks) {\n    if (task.triggers.length > 0) bumpStep = true;\n    checkpoint.versions_seen[task.name] ??= {};\n    for (const chan of task.triggers) {\n      if (chan in checkpoint.channel_versions) {\n        checkpoint.versions_seen[task.name][chan] =\n          checkpoint.channel_versions[chan];\n      }\n      if (!RESERVED_SET.has(chan)) {\n        channelsToConsume.add(chan);\n      }\n    }\n  }\n\n  // Find the highest version of all channels\n  let maxVersion = maxChannelMapVersion(checkpoint.channel_versions);\n\n  let usedNewVersion = false;\n  for (const chan of channelsToConsume) {\n    if (chan in onlyChannels && onlyChannels[chan].consume()) {\n      if (getNextVersion !== undefined) {\n        checkpoint.channel_versions[chan] = getNextVersion(maxVersion);\n        usedNewVersion = true;\n      }\n    }\n  }\n\n  // Group writes by channel\n  const pendingWritesByChannel = {} as Record<keyof Cc, PendingWriteValue[]>;\n  // Originating task id per grouped write, used to reorder DeltaChannel writes\n  // below.\n  const pendingWriteTaskIdsByChannel = {} as Record<keyof Cc, string[]>;\n  for (const task of tasks) {\n    const taskId = (task as { id?: string }).id ?? \"\";\n    for (const [chan, val] of task.writes) {\n      if (IGNORE.has(chan)) {\n        // do nothing\n      } else if (chan in onlyChannels) {\n        pendingWritesByChannel[chan] ??= [];\n        pendingWritesByChannel[chan].push(val);\n        pendingWriteTaskIdsByChannel[chan] ??= [];\n        pendingWriteTaskIdsByChannel[chan].push(taskId);\n      }\n    }\n  }\n\n  // Reorder concurrent DeltaChannel writes to match the checkpointer replay\n  // order: task id ascending (byte/string order, matching both MemorySaver and\n  // the Postgres `COLLATE \"C\"` sort). A stable sort keeps each task's writes in\n  // their original `idx` order, so reconstruction (see\n  // `BaseCheckpointSaver.getDeltaChannelHistory`) matches the live value.\n  for (const [chan, vals] of Object.entries(pendingWritesByChannel)) {\n    if (vals.length < 2) continue;\n    if (onlyChannels[chan]?.lc_graph_name !== \"DeltaChannel\") continue;\n    const taskIds = pendingWriteTaskIdsByChannel[chan as keyof Cc];\n    const paired = vals.map((val, i) => ({ val, taskId: taskIds[i] }));\n    paired.sort((a, b) =>\n      a.taskId < b.taskId ? -1 : a.taskId > b.taskId ? 1 : 0\n    );\n    pendingWritesByChannel[chan as keyof Cc] = paired.map((p) => p.val);\n  }\n\n  // Find the highest version of all channels\n  if (maxVersion != null && getNextVersion != null) {\n    maxVersion = usedNewVersion ? getNextVersion(maxVersion) : maxVersion;\n  }\n\n  const updatedChannels: Set<string> = new Set();\n  // Apply writes to channels\n  for (const [chan, vals] of Object.entries(pendingWritesByChannel)) {\n    if (chan in onlyChannels) {\n      const channel = onlyChannels[chan];\n      let updated;\n      try {\n        updated = channel.update(vals);\n        // eslint-disable-next-line @typescript-eslint/no-explicit-any\n      } catch (e: any) {\n        if (e.name === InvalidUpdateError.unminifiable_name) {\n          const wrappedError = new InvalidUpdateError(\n            `Invalid update for channel \"${chan}\" with values ${JSON.stringify(\n              vals\n            )}: ${e.message}`\n          );\n          wrappedError.lc_error_code = e.lc_error_code;\n          throw wrappedError;\n        } else {\n          throw e;\n        }\n      }\n      if (updated && getNextVersion !== undefined) {\n        checkpoint.channel_versions[chan] = getNextVersion(maxVersion);\n\n        // unavailable channels can't trigger tasks, so don't add them\n        if (channel.isAvailable()) updatedChannels.add(chan);\n      }\n    }\n  }\n\n  // Channels that weren't updated in this step are notified of a new step\n  if (bumpStep) {\n    for (const chan in onlyChannels) {\n      if (!Object.prototype.hasOwnProperty.call(onlyChannels, chan)) continue;\n\n      const channel = onlyChannels[chan];\n      if (channel.isAvailable() && !updatedChannels.has(chan)) {\n        const updated = channel.update([]);\n\n        if (updated && getNextVersion !== undefined) {\n          checkpoint.channel_versions[chan] = getNextVersion(maxVersion);\n\n          // unavailable channels can't trigger tasks, so don't add them\n          if (channel.isAvailable()) updatedChannels.add(chan);\n        }\n      }\n    }\n  }\n\n  // If this is (tentatively) the last superstep, notify all channels of finish\n  if (bumpStep && !triggersNextStep(updatedChannels, triggerToNodes)) {\n    for (const chan in onlyChannels) {\n      if (!Object.prototype.hasOwnProperty.call(onlyChannels, chan)) continue;\n\n      const channel = onlyChannels[chan];\n      if (channel.finish() && getNextVersion !== undefined) {\n        checkpoint.channel_versions[chan] = getNextVersion(maxVersion);\n\n        // unavailable channels can't trigger tasks, so don't add them\n        if (channel.isAvailable()) updatedChannels.add(chan);\n      }\n    }\n  }\n\n  return updatedChannels;\n}\n\nfunction* candidateNodes(\n  checkpoint: ReadonlyCheckpoint,\n  processes: StrRecord<string, PregelNode>,\n  extra: NextTaskExtraFields\n) {\n  // This section is an optimization that allows which\n  // nodes will be active during the next step.\n  // When there's information about:\n  // 1. Which channels were updated in the previous step\n  // 2. Which nodes are triggered by which channels\n  // Then we can determine which nodes should be triggered\n  // in the next step without having to cycle through all nodes.\n  if (extra.updatedChannels != null && extra.triggerToNodes != null) {\n    const triggeredNodes = new Set<string>();\n\n    // Get all nodes that have triggers associated with an updated channel\n    for (const channel of extra.updatedChannels) {\n      const nodeIds = extra.triggerToNodes[channel];\n      for (const id of nodeIds ?? []) triggeredNodes.add(id);\n    }\n\n    // Sort the nodes to ensure deterministic order\n    yield* [...triggeredNodes].sort();\n    return;\n  }\n\n  // If there are no values in checkpoint, no need to run\n  // through all the PULL candidates\n  const isEmptyChannelVersions = (() => {\n    for (const chan in checkpoint.channel_versions) {\n      if (checkpoint.channel_versions[chan] !== null) return false;\n    }\n    return true;\n  })();\n\n  if (isEmptyChannelVersions) return;\n  for (const name in processes) {\n    if (!Object.prototype.hasOwnProperty.call(processes, name)) continue;\n    yield name;\n  }\n}\n\n/**\n * Pre-indexed pending writes for O(1) lookups, avoiding repeated\n * linear scans in _prepareSingleTask and _scratchpad.\n */\nexport type PendingWritesIndex = {\n  nullResume: unknown | undefined;\n  resumeByTaskId: Map<string, unknown[]>;\n  successfulWriteTaskIds: Set<string>;\n};\n\n/**\n * Build an index over pendingWrites for O(1) lookups.\n *\n * @internal Exported for benchmarks and regression tests only.\n */\nexport function _indexPendingWrites(\n  pendingWrites: [string, string, unknown][] | undefined\n): PendingWritesIndex {\n  let nullResume: unknown | undefined;\n  const resumeByTaskId = new Map<string, unknown[]>();\n  const successfulWriteTaskIds = new Set<string>();\n  if (pendingWrites) {\n    for (const [tid, chan, val] of pendingWrites) {\n      if (tid === NULL_TASK_ID && chan === RESUME && nullResume === undefined) {\n        nullResume = val;\n      }\n      if (chan === RESUME && tid !== NULL_TASK_ID) {\n        let arr = resumeByTaskId.get(tid);\n        if (!arr) {\n          arr = [];\n          resumeByTaskId.set(tid, arr);\n        }\n        arr.push(val);\n      }\n      if (chan !== ERROR) {\n        successfulWriteTaskIds.add(tid);\n      }\n    }\n  }\n  return { nullResume, resumeByTaskId, successfulWriteTaskIds };\n}\n\nexport type NextTaskExtraFields = {\n  step: number;\n  isResuming?: boolean;\n  checkpointer?: BaseCheckpointSaver;\n  manager?: CallbackManagerForChainRun;\n  store?: BaseStore;\n  stream?: IterableReadableWritableStream;\n  triggerToNodes?: Record<string, string[]>;\n  updatedChannels?: Set<string>;\n  pendingWritesIndex?: PendingWritesIndex;\n};\n\nexport type NextTaskExtraFieldsWithStore = NextTaskExtraFields & {\n  store?: BaseStore;\n};\n\nexport type NextTaskExtraFieldsWithoutStore = NextTaskExtraFields & {\n  store?: never;\n};\n\nexport function _prepareNextTasks<\n  Nn extends StrRecord<string, PregelNode>,\n  Cc extends StrRecord<string, BaseChannel>,\n>(\n  checkpoint: ReadonlyCheckpoint,\n  pendingWrites: [string, string, unknown][] | undefined,\n  processes: Nn,\n  channels: Cc,\n  config: RunnableConfig,\n  forExecution: false,\n  extra: NextTaskExtraFieldsWithoutStore\n): Record<string, PregelTaskDescription>;\n\nexport function _prepareNextTasks<\n  Nn extends StrRecord<string, PregelNode>,\n  Cc extends StrRecord<string, BaseChannel>,\n>(\n  checkpoint: ReadonlyCheckpoint,\n  pendingWrites: [string, string, unknown][] | undefined,\n  processes: Nn,\n  channels: Cc,\n  config: RunnableConfig,\n  forExecution: true,\n  extra: NextTaskExtraFieldsWithStore\n): Record<string, PregelExecutableTask<keyof Nn, keyof Cc>>;\n\n/**\n * Prepare the set of tasks that will make up the next Pregel step.\n * This is the union of all PUSH tasks (Sends) and PULL tasks (nodes triggered\n * by edges).\n */\nexport function _prepareNextTasks<\n  Nn extends StrRecord<string, PregelNode>,\n  Cc extends StrRecord<string, BaseChannel>,\n>(\n  checkpoint: ReadonlyCheckpoint,\n  pendingWrites: [string, string, unknown][] | undefined,\n  processes: Nn,\n  channels: Cc,\n  config: RunnableConfig,\n  forExecution: boolean,\n  extra: NextTaskExtraFieldsWithStore | NextTaskExtraFieldsWithoutStore\n):\n  | Record<string, PregelTaskDescription>\n  | Record<string, PregelExecutableTask<keyof Nn, keyof Cc>> {\n  const tasks:\n    | Record<string, PregelExecutableTask<keyof Nn, keyof Cc>>\n    | Record<string, PregelTaskDescription> = {};\n\n  // Pre-index pendingWrites once for O(1) lookups in _prepareSingleTask/_scratchpad\n  const indexedExtra: typeof extra = extra.pendingWritesIndex\n    ? extra\n    : { ...extra, pendingWritesIndex: _indexPendingWrites(pendingWrites) };\n\n  // Consume pending tasks\n  const tasksChannel = channels[TASKS] as Topic<SendProtocol> | undefined;\n\n  if (tasksChannel?.isAvailable()) {\n    const len = tasksChannel.get().length;\n    for (let i = 0; i < len; i += 1) {\n      const task = _prepareSingleTask(\n        [PUSH, i],\n        checkpoint,\n        pendingWrites,\n        processes,\n        channels,\n        config,\n        forExecution,\n        indexedExtra\n      );\n      if (task !== undefined) {\n        tasks[task.id] = task;\n      }\n    }\n  }\n\n  // Check if any processes should be run in next step\n  // If so, prepare the values to be passed to them\n  for (const name of candidateNodes(checkpoint, processes, indexedExtra)) {\n    const task = _prepareSingleTask(\n      [PULL, name],\n      checkpoint,\n      pendingWrites,\n      processes,\n      channels,\n      config,\n      forExecution,\n      indexedExtra\n    );\n    if (task !== undefined) {\n      tasks[task.id] = task;\n    }\n  }\n  return tasks;\n}\n\nexport function _prepareSingleTask<\n  Nn extends StrRecord<string, PregelNode>,\n  Cc extends StrRecord<string, BaseChannel>,\n>(\n  taskPath: SimpleTaskPath,\n  checkpoint: ReadonlyCheckpoint,\n  pendingWrites: CheckpointPendingWrite[] | undefined,\n  processes: Nn,\n  channels: Cc,\n  config: RunnableConfig,\n  forExecution: false,\n  extra: NextTaskExtraFields\n): PregelTaskDescription | undefined;\n\nexport function _prepareSingleTask<\n  Nn extends StrRecord<string, PregelNode>,\n  Cc extends StrRecord<string, BaseChannel>,\n>(\n  taskPath: TaskPath,\n  checkpoint: ReadonlyCheckpoint,\n  pendingWrites: CheckpointPendingWrite[] | undefined,\n  processes: Nn,\n  channels: Cc,\n  config: RunnableConfig,\n  forExecution: true,\n  extra: NextTaskExtraFields\n): PregelExecutableTask<keyof Nn, keyof Cc> | undefined;\n\nexport function _prepareSingleTask<\n  Nn extends StrRecord<string, PregelNode>,\n  Cc extends StrRecord<string, BaseChannel>,\n>(\n  taskPath: TaskPath,\n  checkpoint: ReadonlyCheckpoint,\n  pendingWrites: CheckpointPendingWrite[] | undefined,\n  processes: Nn,\n  channels: Cc,\n  config: RunnableConfig,\n  forExecution: boolean,\n  extra: NextTaskExtraFieldsWithStore\n): PregelTaskDescription | PregelExecutableTask<keyof Nn, keyof Cc> | undefined;\n\n/**\n * Prepares a single task for the next Pregel step, given a task path, which\n * uniquely identifies a PUSH or PULL task within the graph.\n */\nexport function _prepareSingleTask<\n  Nn extends StrRecord<string, PregelNode>,\n  Cc extends StrRecord<string, BaseChannel>,\n>(\n  taskPath: TaskPath,\n  checkpoint: ReadonlyCheckpoint,\n  pendingWrites: CheckpointPendingWrite[] | undefined,\n  processes: Nn,\n  channels: Cc,\n  config: LangGraphRunnableConfig,\n  forExecution: boolean,\n  extra: NextTaskExtraFields\n):\n  | PregelTaskDescription\n  | PregelExecutableTask<keyof Nn, keyof Cc>\n  | undefined {\n  const { step, checkpointer, manager } = extra;\n  const configurable = config.configurable ?? {};\n  const parentNamespace = configurable.checkpoint_ns ?? \"\";\n\n  if (taskPath[0] === PUSH && isCall(taskPath[taskPath.length - 1])) {\n    const call = taskPath[taskPath.length - 1] as Call;\n    const proc = getRunnableForFunc(call.name, call.func);\n    const triggers = [PUSH];\n    const checkpointNamespace =\n      parentNamespace === \"\"\n        ? call.name\n        : `${parentNamespace}${CHECKPOINT_NAMESPACE_SEPARATOR}${call.name}`;\n    const id = uuid5(\n      JSON.stringify([\n        checkpointNamespace,\n        step.toString(),\n        call.name,\n        PUSH,\n        taskPath[1],\n        taskPath[2],\n      ]),\n      checkpoint.id\n    );\n    const taskCheckpointNamespace = `${checkpointNamespace}${CHECKPOINT_NAMESPACE_END}${id}`;\n\n    // we append `true` to the task path to indicate that a call is being made\n    // so we should not return interrupts from this task (responsibility lies with the parent)\n    const outputTaskPath = [...taskPath.slice(0, 3), true] as VariadicTaskPath;\n    const metadata = {\n      langgraph_step: step,\n      langgraph_node: call.name,\n      langgraph_triggers: triggers,\n      langgraph_path: outputTaskPath,\n      langgraph_checkpoint_ns: taskCheckpointNamespace,\n      checkpoint_ns: taskCheckpointNamespace,\n    };\n    if (forExecution) {\n      const writes: [keyof Cc, unknown][] = [];\n      const executionInfo: ExecutionInfo = {\n        checkpointId: checkpoint.id,\n        checkpointNs: taskCheckpointNamespace,\n        taskId: id,\n        threadId: configurable.thread_id as string | undefined,\n        runId: config.runId != null ? String(config.runId) : undefined,\n        nodeAttempt: 1,\n      };\n      const task = {\n        name: call.name,\n        input: call.input,\n        proc,\n        writes,\n        config: {\n          ...patchConfig(\n            mergeConfigs(config, {\n              metadata,\n              store: extra.store ?? config.store,\n            }),\n            {\n              runName: call.name,\n              callbacks: manager?.getChild(`graph:step:${step}`),\n              configurable: {\n                [CONFIG_KEY_TASK_ID]: id,\n                [CONFIG_KEY_SEND]: (writes_: PendingWrite[]) =>\n                  _localWrite(\n                    (items: PendingWrite<keyof Cc>[]) => writes.push(...items),\n                    processes,\n                    writes_\n                  ),\n                [CONFIG_KEY_READ]: (\n                  select_: Array<keyof Cc> | keyof Cc,\n                  fresh_: boolean = false\n                ) =>\n                  _localRead(\n                    checkpoint,\n                    channels,\n                    {\n                      name: call.name,\n                      writes: writes as PendingWrite[],\n                      triggers,\n                      path: outputTaskPath,\n                    },\n                    select_,\n                    fresh_\n                  ),\n                [CONFIG_KEY_CHECKPOINTER]:\n                  checkpointer ?? configurable[CONFIG_KEY_CHECKPOINTER],\n                [CONFIG_KEY_CHECKPOINT_MAP]: {\n                  ...configurable[CONFIG_KEY_CHECKPOINT_MAP],\n                  [parentNamespace]: checkpoint.id,\n                },\n                [CONFIG_KEY_SCRATCHPAD]: _scratchpad({\n                  pendingWrites: pendingWrites ?? [],\n                  taskId: id,\n                  currentTaskInput: call.input,\n                  resumeMap: config.configurable?.[CONFIG_KEY_RESUME_MAP],\n                  namespaceHash: XXH3(taskCheckpointNamespace),\n                  pendingWritesIndex: extra.pendingWritesIndex,\n                }),\n                [CONFIG_KEY_PREVIOUS_STATE]:\n                  checkpoint.channel_values[PREVIOUS],\n                checkpoint_id: undefined,\n                checkpoint_ns: taskCheckpointNamespace,\n              },\n            }\n          ),\n          executionInfo,\n        },\n        triggers,\n        retry_policy: call.retry,\n        cache_key: call.cache\n          ? {\n              key: XXH3((call.cache.keyFunc ?? JSON.stringify)([call.input])),\n              ns: [CACHE_NS_WRITES, call.name ?? \"__dynamic__\"],\n              ttl: call.cache.ttl,\n            }\n          : undefined,\n        id,\n        path: outputTaskPath,\n        writers: [],\n        timeout: call.timeout,\n      } satisfies PregelExecutableTask<keyof Nn, keyof Cc>;\n      return task;\n    } else {\n      return {\n        id,\n        name: call.name,\n        interrupts: [],\n        path: outputTaskPath,\n      };\n    }\n  } else if (taskPath[0] === PUSH) {\n    const index =\n      typeof taskPath[1] === \"number\"\n        ? taskPath[1]\n        : parseInt(taskPath[1] as string, 10);\n\n    if (!channels[TASKS]?.isAvailable()) {\n      return undefined;\n    }\n\n    const sends = channels[TASKS].get() as SendProtocol[];\n    if (index < 0 || index >= sends.length) {\n      return undefined;\n    }\n\n    const packet =\n      _isSendInterface(sends[index]) && !_isSend(sends[index])\n        ? new Send(\n            sends[index].node,\n            sends[index].args,\n            sends[index].timeout !== undefined\n              ? { timeout: sends[index].timeout }\n              : undefined\n          )\n        : sends[index];\n\n    if (!_isSendInterface(packet)) {\n      console.warn(\n        `Ignoring invalid packet ${JSON.stringify(packet)} in pending sends.`\n      );\n      return undefined;\n    }\n    if (!(packet.node in processes)) {\n      console.warn(\n        `Ignoring unknown node name ${packet.node} in pending sends.`\n      );\n      return undefined;\n    }\n    const triggers = [PUSH];\n    const checkpointNamespace =\n      parentNamespace === \"\"\n        ? packet.node\n        : `${parentNamespace}${CHECKPOINT_NAMESPACE_SEPARATOR}${packet.node}`;\n    const taskId = uuid5(\n      JSON.stringify([\n        checkpointNamespace,\n        step.toString(),\n        packet.node,\n        PUSH,\n        index.toString(),\n      ]),\n      checkpoint.id\n    );\n    const taskCheckpointNamespace = `${checkpointNamespace}${CHECKPOINT_NAMESPACE_END}${taskId}`;\n    let metadata = {\n      langgraph_step: step,\n      langgraph_node: packet.node,\n      langgraph_triggers: triggers,\n      langgraph_path: taskPath.slice(0, 3),\n      langgraph_checkpoint_ns: taskCheckpointNamespace,\n      checkpoint_ns: taskCheckpointNamespace,\n    };\n    if (forExecution) {\n      const proc = processes[packet.node];\n      const node = proc.getNode();\n      if (node !== undefined) {\n        if (proc.metadata !== undefined) {\n          metadata = { ...metadata, ...proc.metadata };\n        }\n        const writes: [keyof Cc, unknown][] = [];\n        const executionInfo: ExecutionInfo = {\n          checkpointId: checkpoint.id,\n          checkpointNs: taskCheckpointNamespace,\n          taskId,\n          threadId: configurable.thread_id as string | undefined,\n          runId: config.runId != null ? String(config.runId) : undefined,\n          nodeAttempt: 1,\n        };\n        return {\n          name: packet.node,\n          input: packet.args,\n          proc: node,\n          subgraphs: proc.subgraphs,\n          writes,\n          config: {\n            ...patchConfig(\n              mergeConfigs(config, {\n                metadata,\n                tags: proc.tags,\n                store: extra.store ?? config.store,\n              }),\n              {\n                runName: packet.node,\n                callbacks: manager?.getChild(`graph:step:${step}`),\n                configurable: {\n                  [CONFIG_KEY_TASK_ID]: taskId,\n                  [CONFIG_KEY_SEND]: (writes_: PendingWrite[]) =>\n                    _localWrite(\n                      (items: PendingWrite<keyof Cc>[]) =>\n                        writes.push(...items),\n                      processes,\n                      writes_\n                    ),\n                  [CONFIG_KEY_READ]: (\n                    select_: Array<keyof Cc> | keyof Cc,\n                    fresh_: boolean = false\n                  ) =>\n                    _localRead(\n                      checkpoint,\n                      channels,\n                      {\n                        name: packet.node,\n                        writes: writes as PendingWrite[],\n                        triggers,\n                        path: taskPath,\n                      },\n                      select_,\n                      fresh_\n                    ),\n                  [CONFIG_KEY_CHECKPOINTER]:\n                    checkpointer ?? configurable[CONFIG_KEY_CHECKPOINTER],\n                  [CONFIG_KEY_CHECKPOINT_MAP]: {\n                    ...configurable[CONFIG_KEY_CHECKPOINT_MAP],\n                    [parentNamespace]: checkpoint.id,\n                  },\n                  [CONFIG_KEY_SCRATCHPAD]: _scratchpad({\n                    pendingWrites: pendingWrites ?? [],\n                    taskId,\n                    currentTaskInput: packet.args,\n                    resumeMap: config.configurable?.[CONFIG_KEY_RESUME_MAP],\n                    namespaceHash: XXH3(taskCheckpointNamespace),\n                    pendingWritesIndex: extra.pendingWritesIndex,\n                  }),\n                  [CONFIG_KEY_PREVIOUS_STATE]:\n                    checkpoint.channel_values[PREVIOUS],\n                  checkpoint_id: undefined,\n                  checkpoint_ns: taskCheckpointNamespace,\n                },\n              }\n            ),\n            executionInfo,\n          },\n          triggers,\n          retry_policy: proc.retryPolicy,\n          cache_key: proc.cachePolicy\n            ? {\n                key: XXH3(\n                  (proc.cachePolicy.keyFunc ?? JSON.stringify)([packet.args])\n                ),\n                ns: [CACHE_NS_WRITES, proc.name ?? \"__dynamic__\", packet.node],\n                ttl: proc.cachePolicy.ttl,\n              }\n            : undefined,\n          id: taskId,\n          path: taskPath,\n          writers: proc.getWriters(),\n          // a per-Send timeout overrides the target node's configured timeout\n          timeout: packet.timeout ?? proc.timeout,\n        } satisfies PregelExecutableTask<keyof Nn, keyof Cc>;\n      }\n    } else {\n      return {\n        id: taskId,\n        name: packet.node,\n        interrupts: [],\n        path: taskPath,\n      } satisfies PregelTaskDescription;\n    }\n  } else if (taskPath[0] === PULL) {\n    const name = taskPath[1].toString();\n    const proc = processes[name];\n    if (proc === undefined) {\n      return undefined;\n    }\n\n    // Check if this task already has successful writes in the pending writes\n    if (pendingWrites?.length) {\n      // Find the task ID for this node/path\n      const checkpointNamespace =\n        parentNamespace === \"\"\n          ? name\n          : `${parentNamespace}${CHECKPOINT_NAMESPACE_SEPARATOR}${name}`;\n\n      const taskId = uuid5(\n        JSON.stringify([\n          checkpointNamespace,\n          step.toString(),\n          name,\n          PULL,\n          name,\n        ]),\n        checkpoint.id\n      );\n\n      const hasSuccessfulWrites = extra.pendingWritesIndex\n        ? extra.pendingWritesIndex.successfulWriteTaskIds.has(taskId)\n        : pendingWrites.some((w) => w[0] === taskId && w[1] !== ERROR);\n\n      if (hasSuccessfulWrites) {\n        return undefined;\n      }\n    }\n\n    const nullVersion = getNullChannelVersion(checkpoint.channel_versions);\n    if (nullVersion === undefined) {\n      return undefined;\n    }\n    const seen = checkpoint.versions_seen[name] ?? {};\n\n    // Find the first trigger that is available and has a new version\n    const trigger = proc.triggers.find((chan) => {\n      if (!channels[chan].isAvailable()) return false;\n\n      return (\n        (checkpoint.channel_versions[chan] ?? nullVersion) >\n        (seen[chan] ?? nullVersion)\n      );\n    });\n\n    // If any of the channels read by this process were updated\n    if (trigger !== undefined) {\n      const val = _procInput(proc, channels, forExecution);\n      if (val === undefined) {\n        return undefined;\n      }\n      const checkpointNamespace =\n        parentNamespace === \"\"\n          ? name\n          : `${parentNamespace}${CHECKPOINT_NAMESPACE_SEPARATOR}${name}`;\n      const taskId = uuid5(\n        JSON.stringify([\n          checkpointNamespace,\n          step.toString(),\n          name,\n          PULL,\n          [trigger],\n        ]),\n        checkpoint.id\n      );\n      const taskCheckpointNamespace = `${checkpointNamespace}${CHECKPOINT_NAMESPACE_END}${taskId}`;\n      let metadata = {\n        langgraph_step: step,\n        langgraph_node: name,\n        langgraph_triggers: [trigger],\n        langgraph_path: taskPath,\n        langgraph_checkpoint_ns: taskCheckpointNamespace,\n        checkpoint_ns: taskCheckpointNamespace,\n      };\n      if (forExecution) {\n        const node = proc.getNode();\n        if (node !== undefined) {\n          if (proc.metadata !== undefined) {\n            metadata = { ...metadata, ...proc.metadata };\n          }\n          const writes: [keyof Cc, unknown][] = [];\n          const executionInfo: ExecutionInfo = {\n            checkpointId: checkpoint.id,\n            checkpointNs: taskCheckpointNamespace,\n            taskId,\n            threadId: configurable.thread_id as string | undefined,\n            runId: config.runId != null ? String(config.runId) : undefined,\n            nodeAttempt: 1,\n          };\n          return {\n            name,\n            input: val,\n            proc: node,\n            subgraphs: proc.subgraphs,\n            writes,\n            config: {\n              ...patchConfig(\n                mergeConfigs(config, {\n                  metadata,\n                  tags: proc.tags,\n                  store: extra.store ?? config.store,\n                }),\n                {\n                  runName: name,\n                  callbacks: manager?.getChild(`graph:step:${step}`),\n                  configurable: {\n                    [CONFIG_KEY_TASK_ID]: taskId,\n                    [CONFIG_KEY_SEND]: (writes_: PendingWrite[]) =>\n                      _localWrite(\n                        (items: PendingWrite<keyof Cc>[]) => {\n                          writes.push(...items);\n                        },\n                        processes,\n                        writes_\n                      ),\n                    [CONFIG_KEY_READ]: (\n                      select_: Array<keyof Cc> | keyof Cc,\n                      fresh_: boolean = false\n                    ) =>\n                      _localRead(\n                        checkpoint,\n                        channels,\n                        {\n                          name,\n                          writes: writes as PendingWrite[],\n                          triggers: [trigger],\n                          path: taskPath,\n                        },\n                        select_,\n                        fresh_\n                      ),\n                    [CONFIG_KEY_CHECKPOINTER]:\n                      checkpointer ?? configurable[CONFIG_KEY_CHECKPOINTER],\n                    [CONFIG_KEY_CHECKPOINT_MAP]: {\n                      ...configurable[CONFIG_KEY_CHECKPOINT_MAP],\n                      [parentNamespace]: checkpoint.id,\n                    },\n                    [CONFIG_KEY_SCRATCHPAD]: _scratchpad({\n                      pendingWrites: pendingWrites ?? [],\n                      taskId,\n                      currentTaskInput: val,\n                      resumeMap: config.configurable?.[CONFIG_KEY_RESUME_MAP],\n                      namespaceHash: XXH3(taskCheckpointNamespace),\n                      pendingWritesIndex: extra.pendingWritesIndex,\n                    }),\n                    [CONFIG_KEY_PREVIOUS_STATE]:\n                      checkpoint.channel_values[PREVIOUS],\n                    checkpoint_id: undefined,\n                    checkpoint_ns: taskCheckpointNamespace,\n                  },\n                }\n              ),\n              executionInfo,\n            },\n            triggers: [trigger],\n            retry_policy: proc.retryPolicy,\n            cache_key: proc.cachePolicy\n              ? {\n                  key: XXH3(\n                    (proc.cachePolicy.keyFunc ?? JSON.stringify)([val])\n                  ),\n                  ns: [CACHE_NS_WRITES, proc.name ?? \"__dynamic__\", name],\n                  ttl: proc.cachePolicy.ttl,\n                }\n              : undefined,\n            id: taskId,\n            path: taskPath,\n            writers: proc.getWriters(),\n            timeout: proc.timeout,\n          } satisfies PregelExecutableTask<keyof Nn, keyof Cc>;\n        }\n      } else {\n        return {\n          id: taskId,\n          name,\n          interrupts: [],\n          path: taskPath,\n        } satisfies PregelTaskDescription;\n      }\n    }\n  }\n  return undefined;\n}\n\n/**\n * Prepare an immediate node-level error handler task for a failed task.\n *\n * The handler runs only after the failed node's retry policy is exhausted (the\n * runner schedules it once a non-bubble-up error settles). It is prepared like\n * a PUSH task targeting the auto-generated handler node, receives the failed\n * node's input, and is injected with a {@link NodeError} under\n * {@link CONFIG_KEY_NODE_ERROR} so the handler can inspect the failure\n * provenance (and route via `Command({ goto })`).\n *\n * @internal\n */\nexport function _prepareNodeErrorHandlerTask<\n  Nn extends StrRecord<string, PregelNode>,\n  Cc extends StrRecord<string, BaseChannel>,\n>(\n  failedTask: PregelExecutableTask<keyof Nn, keyof Cc>,\n  handlerNodeName: string,\n  error: Error,\n  checkpoint: ReadonlyCheckpoint,\n  pendingWrites: CheckpointPendingWrite[] | undefined,\n  processes: Nn,\n  channels: Cc,\n  config: LangGraphRunnableConfig,\n  extra: NextTaskExtraFieldsWithStore\n): PregelExecutableTask<keyof Nn, keyof Cc> | undefined {\n  const { step, checkpointer, manager } = extra;\n  const proc = processes[handlerNodeName as keyof Nn];\n  if (proc === undefined) {\n    return undefined;\n  }\n  const node = proc.getNode();\n  if (node === undefined) {\n    return undefined;\n  }\n\n  const configurable = config.configurable ?? {};\n  const parentNamespace = configurable.checkpoint_ns ?? \"\";\n  const triggers = [PUSH];\n  const checkpointNamespace =\n    parentNamespace === \"\"\n      ? handlerNodeName\n      : `${parentNamespace}${CHECKPOINT_NAMESPACE_SEPARATOR}${handlerNodeName}`;\n  // Deterministic task id (includes the failed task id) so resuming from a\n  // checkpoint reconstructs the same handler task.\n  const taskId = uuid5(\n    JSON.stringify([\n      checkpointNamespace,\n      step.toString(),\n      handlerNodeName,\n      PUSH,\n      \"node_error_handler\",\n      failedTask.id,\n    ]),\n    checkpoint.id\n  );\n  const taskCheckpointNamespace = `${checkpointNamespace}${CHECKPOINT_NAMESPACE_END}${taskId}`;\n  // Last path element is a string (not `true`), so interrupts raised by the\n  // handler are surfaced normally rather than deferred to a parent call.\n  const taskPath = [\n    PUSH,\n    String(failedTask.name),\n    handlerNodeName,\n    false,\n  ] as VariadicTaskPath;\n\n  let metadata = {\n    langgraph_step: step,\n    langgraph_node: handlerNodeName,\n    langgraph_triggers: triggers,\n    langgraph_path: taskPath,\n    langgraph_checkpoint_ns: taskCheckpointNamespace,\n    checkpoint_ns: taskCheckpointNamespace,\n  };\n  if (proc.metadata !== undefined) {\n    metadata = { ...metadata, ...proc.metadata };\n  }\n\n  const writes: [keyof Cc, unknown][] = [];\n  const executionInfo: ExecutionInfo = {\n    checkpointId: checkpoint.id,\n    checkpointNs: taskCheckpointNamespace,\n    taskId,\n    threadId: configurable.thread_id as string | undefined,\n    runId: config.runId != null ? String(config.runId) : undefined,\n    nodeAttempt: 1,\n  };\n\n  return {\n    name: handlerNodeName as keyof Nn,\n    input: failedTask.input,\n    proc: node,\n    subgraphs: proc.subgraphs,\n    writes,\n    config: {\n      ...patchConfig(\n        mergeConfigs(config, {\n          metadata,\n          tags: proc.tags,\n          store: extra.store ?? config.store,\n        }),\n        {\n          runName: handlerNodeName,\n          callbacks: manager?.getChild(`graph:step:${step}`),\n          configurable: {\n            [CONFIG_KEY_TASK_ID]: taskId,\n            [CONFIG_KEY_SEND]: (writes_: PendingWrite[]) =>\n              _localWrite(\n                (items: PendingWrite<keyof Cc>[]) => writes.push(...items),\n                processes,\n                writes_\n              ),\n            [CONFIG_KEY_READ]: (\n              select_: Array<keyof Cc> | keyof Cc,\n              fresh_: boolean = false\n            ) =>\n              _localRead(\n                checkpoint,\n                channels,\n                {\n                  name: handlerNodeName,\n                  writes: writes as PendingWrite[],\n                  triggers,\n                  path: taskPath,\n                },\n                select_,\n                fresh_\n              ),\n            [CONFIG_KEY_CHECKPOINTER]:\n              checkpointer ?? configurable[CONFIG_KEY_CHECKPOINTER],\n            [CONFIG_KEY_CHECKPOINT_MAP]: {\n              ...configurable[CONFIG_KEY_CHECKPOINT_MAP],\n              [parentNamespace]: checkpoint.id,\n            },\n            [CONFIG_KEY_SCRATCHPAD]: _scratchpad({\n              pendingWrites: pendingWrites ?? [],\n              taskId,\n              currentTaskInput: failedTask.input,\n              resumeMap: config.configurable?.[CONFIG_KEY_RESUME_MAP],\n              namespaceHash: XXH3(taskCheckpointNamespace),\n            }),\n            [CONFIG_KEY_PREVIOUS_STATE]: checkpoint.channel_values[PREVIOUS],\n            [CONFIG_KEY_NODE_ERROR]: new NodeError(\n              String(failedTask.name),\n              error\n            ),\n            checkpoint_id: undefined,\n            checkpoint_ns: taskCheckpointNamespace,\n          },\n        }\n      ),\n      executionInfo,\n    },\n    triggers,\n    retry_policy: proc.retryPolicy,\n    cache_key: undefined,\n    id: taskId,\n    path: taskPath,\n    writers: proc.getWriters(),\n  } satisfies PregelExecutableTask<keyof Nn, keyof Cc>;\n}\n\n/**\n *  Function injected under CONFIG_KEY_READ in task config, to read current state.\n *  Used by conditional edges to read a copy of the state with reflecting the writes\n *  from that node only.\n *\n * @internal\n */\nfunction _procInput(\n  proc: PregelNode,\n  channels: StrRecord<string, BaseChannel>,\n  forExecution: boolean\n) {\n  // eslint-disable-next-line @typescript-eslint/no-explicit-any\n  let val: any;\n\n  if (typeof proc.channels === \"object\" && !Array.isArray(proc.channels)) {\n    val = {};\n    for (const [k, chan] of Object.entries(proc.channels)) {\n      if (proc.triggers.includes(chan)) {\n        try {\n          val[k] = readChannel(channels, chan, false);\n          // eslint-disable-next-line @typescript-eslint/no-explicit-any\n        } catch (e: any) {\n          if (e.name === EmptyChannelError.unminifiable_name) {\n            return undefined;\n          } else {\n            throw e;\n          }\n        }\n      } else if (chan in channels) {\n        try {\n          val[k] = readChannel(channels, chan, false);\n          // eslint-disable-next-line @typescript-eslint/no-explicit-any\n        } catch (e: any) {\n          if (e.name === EmptyChannelError.unminifiable_name) {\n            continue;\n          } else {\n            throw e;\n          }\n        }\n      }\n    }\n  } else if (Array.isArray(proc.channels)) {\n    let successfulRead = false;\n    for (const chan of proc.channels) {\n      try {\n        val = readChannel(channels, chan, false);\n        successfulRead = true;\n        break;\n        // eslint-disable-next-line @typescript-eslint/no-explicit-any\n      } catch (e: any) {\n        if (e.name === EmptyChannelError.unminifiable_name) {\n          continue;\n        } else {\n          throw e;\n        }\n      }\n    }\n    if (!successfulRead) {\n      return undefined;\n    }\n  } else {\n    throw new Error(\n      `Invalid channels type, expected list or dict, got ${proc.channels}`\n    );\n  }\n\n  // If the process has a mapper, apply it to the value\n  if (forExecution && proc.mapper !== undefined) {\n    val = proc.mapper(val);\n  }\n\n  return val;\n}\n\n/**\n * Remove any values belonging to UntrackedValue channels from a Send packet\n * before checkpointing.\n *\n * Send is often called with state to be passed to the destination node,\n * which may contain UntrackedValues at the top level.\n *\n * @internal\n */\nexport function sanitizeUntrackedValuesInSend(\n  packet: Send,\n  channels: StrRecord<string, BaseChannel>\n): Send {\n  if (typeof packet.args !== \"object\" || packet.args === null) {\n    // Not a dict-like arg\n    return packet;\n  }\n\n  // Top-level keys should be channel names\n  const sanitizedArg: Record<string, unknown> = {};\n  for (const [key, value] of Object.entries(packet.args)) {\n    const channel = channels[key];\n    // Check if channel is an UntrackedValue by its lc_graph_name\n    if (!channel || channel.lc_graph_name !== \"UntrackedValue\") {\n      sanitizedArg[key] = value;\n    }\n  }\n\n  return new Send(packet.node, sanitizedArg);\n}\n\nfunction _scratchpad({\n  pendingWrites,\n  taskId,\n  currentTaskInput,\n  resumeMap,\n  namespaceHash,\n  pendingWritesIndex,\n}: {\n  pendingWrites: CheckpointPendingWrite[];\n  taskId: string;\n  currentTaskInput: unknown;\n  resumeMap: Record<string, unknown> | undefined;\n  namespaceHash: string;\n  pendingWritesIndex?: PendingWritesIndex;\n}): PregelScratchpad {\n  const nullResume = pendingWritesIndex\n    ? pendingWritesIndex.nullResume\n    : pendingWrites.find(\n        ([writeTaskId, chan]) => writeTaskId === NULL_TASK_ID && chan === RESUME\n      )?.[2];\n\n  const resume = (() => {\n    // flatMap flattens array resume values one level; mirror that with .flat()\n    const result: unknown[] = pendingWritesIndex\n      ? (pendingWritesIndex.resumeByTaskId.get(taskId) ?? []).flat()\n      : pendingWrites\n          .filter(\n            ([writeTaskId, chan]) => writeTaskId === taskId && chan === RESUME\n          )\n          .flatMap(([_writeTaskId, _chan, resume]) => resume);\n\n    if (resumeMap != null && namespaceHash in resumeMap) {\n      const mappedResume = resumeMap[namespaceHash];\n      result.push(mappedResume);\n    }\n\n    return result;\n  })();\n\n  const scratchpad = {\n    callCounter: 0,\n    interruptCounter: -1,\n    resume,\n    nullResume,\n    subgraphCounter: 0,\n    currentTaskInput,\n    consumeNullResume: () => {\n      if (scratchpad.nullResume) {\n        delete scratchpad.nullResume;\n        pendingWrites.splice(\n          pendingWrites.findIndex(\n            ([writeTaskId, chan]) =>\n              writeTaskId === NULL_TASK_ID && chan === RE