OrientDB importer silently drops composite indexes/unique constraints (and can NPE on a missing nullValuesIgnored) #6750

Summary

The OrientDB importer silently drops composite (multi-field) indexes, so a multi-column UNIQUE constraint enforced by the source database is lost after migration and duplicates can then be inserted. A missing optional field on the same path can also abort index creation entirely with an unboxing NPE.

Where (HEAD af4f67fd2)

integration/src/main/java/com/arcadedb/integration/importer/OrientDBImporter.java:1045-1058 (createIndexes):

final String fieldName = (String) indexDefinition.get("field");     // null for a composite index
final String[] properties = new String[]{fieldName};
boolean nullValuesIgnored = (boolean) indexDefinition.get("nullValuesIgnored");   // NPE if absent
...
if (!type.existsPolymorphicProperty(fieldName)) {
  if (keyType == null) { /* verbose warning */ ++warnings; continue; }            // index dropped

The code only understands the single-property OPropertyIndexDefinition shape. An OCompositeIndexDefinition (JSON key indexDefinitions: [...], no top-level "field"/"keyType") yields fieldName == null and keyType == null, so the index is skipped with only a verbose-level warning.

Repro

Export an OrientDB database with CREATE INDEX Person.name_surname ON Person(firstName, lastName) UNIQUE, then IMPORT DATABASE it. Expected: a composite unique index on [firstName, lastName]. Actual: no index; duplicate (firstName, lastName) pairs that OrientDB rejected are now insertable.

Secondary: if a composite indexDefinition omits nullValuesIgnored, line 1047 unboxes (boolean) null → NullPointerException, aborting createIndexes() for the whole import.

Suggested fix

Detect an indexDefinitionClass ending in OCompositeIndexDefinition and read its indexDefinitions array to build the full property list (and per-field key types); guard the nullValuesIgnored unboxing against a missing/null value.

Scope / confidence

Medium — the single-field-only code path is certain at HEAD; the exact composite JSON shape is inferred from OrientDB's exporter (the bundled orientdb-export-small.gz test resource contains only single-field OPropertyIndexDefinition entries, so this path has no coverage).