E-PE0006 — Serialized message has an empty body

Error Type	Protobuf Error
Phase	loading a model via protobuf (`from_protobuf`)
Python exception	`jijmodeling.ProtobufError`

Message

The serialized message has an empty body.

Possible fix: ensure the bytes were produced by JijModeling's protobuf serialization.

Cause

The bytes decode to a message that declares a supported schema version but contains no problem body. This happens when the input was truncated after the version field or was produced by tooling that wrote the version without a problem payload. (A completely empty input fails the schema-version check first and is reported as E-PE0001 with version 0.)

Fix

Check the source of the bytes: confirm the file/stream is the one written by to_protobuf, that it is non-empty, and that it was read in binary mode. Re-export the model from the source if needed.