Inconsistent Paging for GET /shell-descriptors with Large Datasets and Classic Access Control

[efiege]

Current Behavior

The GET /shell-descriptors endpoint returns a reduced amount of result entries for counter party BPNs when using the "Access Control Classic Implementation" with a large amount of ShellDescriptor entries.

Expected Behavior

The GET /shell-descriptors endpoint will return records that are accessible for the counter party BPN and an entry amount according to the page size.

Steps To Reproduce

• Create a "large" amount of shell-descriptors, most probably larger then defined by the granularAccessControlFetchSize property
  • specify specificAssetIds with externalSubjectId set to {{COUNTER_PARTY_BPN}}
• Fetch the GET /shell-descriptors endpoint with Edc-Bpn Header set to {{COUNTER_PARTY_BPN}}
• Receive reduced amount of shell-descriptor records

Suspected Root Cause

The issue could recide in

sldt-digital-twin-registry/backend/src/main/java/org/eclipse/tractusx/semantics/registry/utils/ShellSpecification.java

Lines 73 to 90 in 07f9a65

	private Predicate getAllShellsPredicate( Root<T> root, CriteriaQuery<?> cq, CriteriaBuilder criteriaBuilder, Instant searchValue ) {
	// Join Shell -> ShellIdentifier
	String t = Shell.Fields.identifiers;
	Join<Shell,ShellIdentifier > shellIdentifierShellJoin = root.join( Shell.Fields.identifiers );
	// join ShellIdentifier -> ShellIdentifierExternalSubjectReference -> ShellIdentifierExternalSubjectReferenceKey
	Join<ShellIdentifierExternalSubjectReference,ShellIdentifierExternalSubjectReferenceKey> referenceKeyJoin = shellIdentifierShellJoin.join( ShellIdentifier.Fields.externalSubjectId ).join( ShellIdentifierExternalSubjectReference.Fields.keys );
	return criteriaBuilder.and(
	criteriaBuilder.or(
	criteriaBuilder.equal( referenceKeyJoin.get( ShellIdentifierExternalSubjectReferenceKey.Fields.value ), tenantId ),
	criteriaBuilder.and(
	criteriaBuilder.equal( referenceKeyJoin.get( ShellIdentifierExternalSubjectReferenceKey.Fields.value ), publicWildcardPrefix ),
	criteriaBuilder.in( shellIdentifierShellJoin.get( ShellIdentifier.Fields.key ) ).value( publicWildcardAllowedTypes )
	)
	),
	criteriaBuilder.greaterThan( root.get( sortFieldName ), searchValue )
	);
	}

which creates joins that lead to multiple rows being generated per shell, which could confuse the paging mechanism of spring. The relevant call should come from

sldt-digital-twin-registry/backend/src/main/java/org/eclipse/tractusx/semantics/registry/service/ShellService.java

Line 215 in 07f9a65

Page<Shell> currentPage = shellRepository.findAll( specification, ofSize( granularAccessControlFetchSize ) );