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[DX] GAP-07: SDK's own CreateTask type not registered with msgpack, produces warning on every resume #1500

@AlexBizon

Description

@AlexBizon

Summary

Every --resume run prints a noisy deserialization warning for CreateTask, which is a first-party SDK type. The warning cannot be silenced without patching the SDK or suppressing log output globally.

Observed Output

Deserializing unregistered type uipath.platform.common.interrupt_models.CreateTask
from checkpoint. This will be blocked in a future version.
Add to allowed_msgpack_modules to silence: [('uipath.platform.common.interrupt_models', 'CreateTask')]

Root Cause

CreateTask is defined in uipath.platform.common.interrupt_models but is not auto-registered with the msgpack serializer used for checkpoint persistence. LangGraph's msgpack serializer requires types to be explicitly registered in allowed_msgpack_modules to deserialize them without a warning.

Since CreateTask is a first-party SDK type that the SDK itself places in checkpoints (via interrupt()), users should never have to manually register it.

Workaround

None without patching the SDK or suppressing the warning at the logging level. The suggested fix in the warning message (allowed_msgpack_modules) would require the user to configure LangGraph internals.

Suggested Fix

Auto-register all first-party interrupt model types (at minimum CreateTask, and any other types from uipath.platform.common.interrupt_models) with msgpack on import. This is a one-line fix:

# In the SDK's initialization code
from langgraph.checkpoint.serde.jsonplus import JsonPlusSerializer
# or equivalent msgpack registration

This warning appears on every resume and buries actual errors in the log output, making it harder to spot real problems.

Impact

  • Severity: Low (functional but noisy)
  • Every user of HITL with --resume sees this warning
  • The warning says "This will be blocked in a future version" — when that happens, this becomes a breaking change for all HITL agents

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