fix(generators): normalize trailing newline in Turtle serialization

rdflib's Turtle serializer always emits a trailing double newline.
Normalize to single newline in deterministic_turtle() and the rdflib
fallback path in canonicalize_rdf_graph() for consistent file endings.

Note: CLI print() still adds a newline after serialize()'s trailing
newline. Callers capturing stdout should strip trailing blank lines
(e.g. via sed).

Signed-off-by: Carlo van Driesten <carlo.van-driesten@bmw.de>

Author: jdsika

packages/linkml/src/linkml/generators/jsonldcontextgen.py

@@ -237,8 +237,8 @@ def end_schema(
                 json.dump(frame, f, indent=2, ensure_ascii=False)
 
         if self.deterministic:
-            return self._deterministic_context_json(json.loads(str(as_json(context))), indent=3) + "\n"
-        return str(as_json(context)) + "\n"
+            return self._deterministic_context_json(json.loads(str(as_json(context))), indent=3)
+        return str(as_json(context))
 
     @staticmethod
     def _deterministic_context_json(data: dict, indent: int = 3) -> str:

packages/linkml/src/linkml/utils/generator.py

@@ -307,7 +307,9 @@ def _to_rdflib(term):
         if pfx_s and any(iri.startswith(ns_s) for iri in used_iris):
             result_graph.bind(pfx_s, ns_s)
 
-    return result_graph.serialize(format="turtle")
+    # rdflib's Turtle serializer always emits a trailing double newline;
+    # normalize to a single newline for consistent file endings.
+    return result_graph.serialize(format="turtle").rstrip("\n") + "\n"
 
 
 def deterministic_json(obj: object, indent: int = 3, preserve_list_order_keys: frozenset[str] | None = None) -> str:

packages/linkml/src/linkml/utils/rdf_canonicalize.py

@@ -146,7 +146,10 @@ def canonicalize_rdf_graph(
             "pyoxigraph does not support format %r; falling back to rdflib serializer",
             output_format,
         )
-        return graph.serialize(format=output_format)
+        # rdflib's Turtle serializer emits a trailing double newline;
+        # normalize to single newline for consistent file endings.
+        data = graph.serialize(format=output_format)
+        return data.rstrip("\n") + "\n" if data.endswith("\n") else data
 
     # 1. Transfer rdflib graph to pyoxigraph via N-Triples.
     nt_data = graph.serialize(format="nt")