hasNext fixer

The hasNext fixer detects and repairs broken oco:hasNext chains in author and editor sequences. It uses a three-phase approach: detect anomalies, delete broken chains, and recreate correct ones.

Anomaly detection

The first step is detecting problems in the hasNext chains.

What it detects

Anomaly	Description
Cycles	Chain loops back to an earlier element
Self-loops	Element points to itself
Dangling references	Points to non-existent entity
Multiple heads	Multiple elements claim to be first
Broken chains	Gap in sequence numbering

Running detection

uv run python -m oc_meta.run.find.hasnext_anomalies -c <META_CONFIG> -o <OUTPUT_JSON> [OPTIONS]

Option	Default	Description
-c, --config	-	Path to Meta config file
-o, --output	-	Output JSON file for anomalies
--workers	4	Number of parallel workers

Example:

uv run python -m oc_meta.run.find.hasnext_anomalies \
  -c meta_config.yaml \
  -o hasnext_anomalies.json \
  --workers 8

Output format

The output JSON contains a report with anomalies in a flat list:

{
  "config": "/path/to/meta_config.yaml",
  "rdf_dir": "/path/to/rdf",
  "timestamp": "2025-01-15T10:30:00+00:00",
  "total_brs_analyzed": 50000,
  "total_anomalies": 15,
  "anomalies_by_type": {
    "cycle": 3,
    "self_loop": 5,
    "dangling_has_next": 7
  },
  "anomalies": [
    {
      "anomaly_type": "self_loop",
      "br": "https://w3id.org/oc/meta/br/060/12345",
      "role_type": "author",
      "ars_involved": [
        {
          "ar": "https://w3id.org/oc/meta/ar/060/456",
          "ra": "https://w3id.org/oc/meta/ra/060/789",
          "has_next": ["https://w3id.org/oc/meta/ar/060/456"]
        }
      ],
      "details": "AR 456 hasNext points to itself"
    }
  ]
}

Anomaly types include: self_loop, multiple_has_next, dangling_has_next, no_start_node, multiple_start_nodes, cycle.

Three-phase fix workflow

Phase 1: Generate correction plan

Analyze anomalies and create a plan:

uv run python -m oc_meta.run.patches.has_next \
  -c meta_config.yaml \
  -a hasnext_anomalies.json \
  -o fix_plan.json \
  --csv-output recreate.csv \
  --dry-run

This outputs:

• fix_plan.json - Details of chains to delete

• recreate.csv - CSV input for Meta to recreate correct chains

Phase 2: Delete broken chains

Execute the deletion plan:

uv run python -m oc_meta.run.patches.has_next \
  -c meta_config.yaml \
  --execute fix_plan.json \
  -r https://w3id.org/oc/meta/prov/pa/1

This removes the broken agent role chains from the triplestore with proper provenance.

Phase 3: Recreate correct chains

Run Meta on the generated CSV to create new, correct chains:

uv run python -m oc_meta.run.meta_process -c meta_config_fixer.yaml

Use a config file pointing to recreate.csv as input.

Plan JSON format

{
  "deletions": [
    {
      "br": "https://w3id.org/oc/meta/br/060/12345",
      "chain": [
        "https://w3id.org/oc/meta/ar/060/1",
        "https://w3id.org/oc/meta/ar/060/2"
      ],
      "reason": "cycle_detected"
    }
  ]
}

How correct chains are determined

The script fetches author/editor ordering from external APIs based on the BR’s identifiers:

1. Crossref (for DOIs) - tried first

2. DataCite (for DOIs not in Crossref)

3. PubMed (for PMIDs)

If no API data is available (no identifiers, API error, or empty response), the correction is marked for manual review.