E-PE0100 — Attempted to serialize an unsupported node

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

Message

Internal error: cannot serialize `{...}` to protobuf.

This construct is not supported by JijModeling's protobuf serialization.

This is a bug in JijModeling - please report it to the developers in community Discord (https://discord.gg/Km5dKF9JjG) with the full error output.

Cause

The serializer encountered an internal node that has no protobuf representation. Such nodes are used only inside the compiler and must never remain in a model that reaches serialization, so this error always indicates a violated internal invariant. No model built through the public Python API should trigger it.

Fix

This is a bug in JijModeling, not in your model. Please report it at the JijModeling community on Discord together with the full error output and, if possible, the model that produced it.