Branch kgc-2025-conformance: explicit rml:TriplesMap statement needed to use TriplesMap as ParentTriplesMap

[elsdvlee]

When using Burp from branch kgc-2025-conformance with this mapping

@prefix rml: <http://w3id.org/rml/> .
@prefix dbo: <http://dbpedia.org/ontology/> .
@prefix foaf: <http://xmlns.com/foaf/0.1/> .

<#AuthorMapping>
    rml:logicalSource <#AuthorsSource> ;
    rml:subjectMap [
        rml:template "http://example.com/author/{id}"
    ] ;
    rml:predicateObjectMap [
        rml:predicate foaf:name ;
        rml:objectMap [
            rml:reference "name"
        ]
    ] .

<#BookMapping>
    rml:logicalSource <#BooksSource> ;
    rml:subjectMap [
        rml:template "http://example.com/book/{id}"
    ] ;
    rml:predicateObjectMap 
        [
            rml:predicate dbo:title ;
            rml:objectMap [
                rml:reference "title"
            ]
        ],
        [
            rml:predicate dbo:author ;
            rml:objectMap [
                rml:parentTriplesMap <#AuthorMapping> ;
                rml:joinCondition [
                    rml:child "author_id" ;
                    rml:parent "id"
                ]
            ]
        ] .

<#AuthorsSource>
    a rml:LogicalSource ;
    rml:source [
        a rml:RelativePathSource ;
        rml:root rml:MappingDirectory ;
        rml:path "authors.json" ;
    ] ;
    rml:referenceFormulation rml:JSONPath ;
    rml:iterator "$[*]" .

<#BooksSource>
    a rml:LogicalSource ;
    rml:source [
        a rml:RelativePathSource ;
        rml:root rml:MappingDirectory ;
        rml:path "books.json" ;
    ] ;
    rml:referenceFormulation rml:JSONPath ;
    rml:iterator "$[*]" .

and inputdata authors.json:

[
  {
    "id": 1,
    "name": "Alice"
  },
  {
    "id": 2,
    "name": "Bob"
  },
  {
    "id": 3,
    "name": "Charlie"
  }
]

and books.json:

[
  {
    "id": 101,
    "title": "RDF Fundamentals",
    "author_id": 1
  },
  {
    "id": 102,
    "title": "Knowledge Graphs Guide",
    "author_id": 2
  },
  {
    "id": 103,
    "title": "Semantic Web Handbook",
    "author_id": 1
  },
  {
    "id": 104,
    "title": "Data Mapping Patterns",
    "author_id": 3
  }
]

I get this error:

SLF4J(W): No SLF4J providers were found.\nSLF4J(W): Defaulting to no-operation (NOP) logger implementation\nSLF4J(W): See https://www.slf4j.org/codes.html#noProviders for further details.\norg.apache.jena.shacl.ValidationReport@c9413d8\njava.lang.RuntimeException: Mapping did not satisfy shapes.\n\tat burp.parse.Parse.parseMappingFile(Parse.java:44)\n\tat burp.Main.doMain(Main.java:53)\n\tat burp.Main.main(Main.java:42)\nMapping did not satisfy shapes.\n",
  "stack": "Error: Error while executing the rules.\n    at ChildProcess.<anonymous> (/home/administrator/rmlmapper-webapi-js/node_modules/@rmlio/rmlmapper-java-wrapper/lib/wrapper.js:210:23)\n    at ChildProcess.emit (node:events:519:28)\n    at maybeClose (node:internal/child_process:1101:16)\n    at ChildProcess._handle.onexit (node:internal/child_process:304:5)

The error disappears when add the following triple to the mapping: <#AuthorMapping> a rml:TriplesMap.