Developer Guide – Loss Mapping

When a target engine cannot express an IR field, we never drop it silently.

Loss-mapping workflow

1. Exporter calls loss.record(json_pointer, field, value, reason, origin)

2. At the end, loss.write() creates output.loss.json side-car.

3. Importer reads side-car and tries to reinject data; status becomes reapplied.

Schema excerpt

{
  "json_pointer": "/tasks/align/resources/gpu",
  "lost_value": 1,
  "reason": "CWL ResourceRequirement has no GPU fields",
  "severity": "warn",
  "status": "lost"
}

CLI integration

• --fail-on-loss aborts if unresolved losses ≥ given severity.

• wf2wf validate checks .loss.json files.