Fix nested list expansion in JSON-LD

rdflib/plugins/parsers/jsonld.py

@@ -281,7 +281,7 @@ def _key_to_graph(
             if term.type == JSON:
                 obj_nodes = [self._to_typed_json_value(obj)]
             elif LIST in term.container:
-                obj_nodes = [{LIST: obj_nodes}]
+                obj_nodes = [self._expand_nested_list(obj_nodes)]
             elif isinstance(obj, dict):
                 obj_nodes = self._parse_container(context, term, obj)
         else:
@@ -333,17 +333,21 @@ def _key_to_graph(
 
         context = context.get_context_for_term(term)
 
-        flattened = []
-        for obj in obj_nodes:
-            if isinstance(obj, dict):
-                objs = context.get_set(obj)
-                if objs is not None:
-                    obj = objs
-            if isinstance(obj, list):
-                flattened += obj
-                continue
-            flattened.append(obj)
-        obj_nodes = flattened
+        # Flatten deep nested lists
+        def flatten(n):
+            flattened = []
+            for obj in n:
+                if isinstance(obj, dict):
+                    objs = context.get_set(obj)
+                    if objs is not None:
+                        obj = objs
+                if isinstance(obj, list):
+                    flattened += flatten(obj)
+                    continue
+                flattened.append(obj)
+            return flattened
+
+        obj_nodes = flatten(obj_nodes)
 
         if not pred_uri:
             return
@@ -593,3 +597,14 @@ def _to_typed_json_value(value: Any) -> Dict[str, str]:
                 value, separators=(",", ":"), sort_keys=True, ensure_ascii=False
             ),
         }
+
+    @staticmethod
+    def _expand_nested_list(obj_nodes):
+        if not isinstance(obj_nodes, list):
+            result = obj_nodes
+        else:
+            result = [
+                Parser._expand_nested_list(o) if isinstance(o, list) else o
+                for o in obj_nodes
+            ]
+        return {LIST: result}

test/jsonld/test_nested_arrays.py

@@ -0,0 +1,76 @@
+# -*- coding: UTF-8 -*-
+
+from rdflib import Graph, Literal, URIRef
+from rdflib.collection import Collection
+
+prop = URIRef("http://example.com/props/a")
+res = URIRef("http://example.com/res")
+
+data_no_container = """
+{
+    "@context": {
+        "a": {
+            "@id": "_PROP_ID_"
+        }
+    },
+    "a": [
+        [[1, 2, 3], ["4", 5]],
+        6,
+        [7, { "@id": "_RES_ID_" }]
+    ]
+}
+""".replace(
+    "_PROP_ID_", str(prop)
+).replace(
+    "_RES_ID_", str(res)
+)
+
+data_list = """
+{
+    "@context": {
+        "a": {
+            "@id": "_PROP_ID_",
+            "@container": "@list"
+        }
+    },
+    "a": [
+        [[1, 2, 3], ["4", 5]],
+        6,
+        [7, { "@id": "_RES_ID_" }]
+    ]
+}
+""".replace(
+    "_PROP_ID_", str(prop)
+).replace(
+    "_RES_ID_", str(res)
+)
+
+
+def test_container_list():
+    g = Graph()
+    g.parse(data=data_list, format="application/ld+json")
+
+    outer = Collection(g, next(g.objects(predicate=prop)))
+    assert len(outer) == 3
+    inner1, inner2, inner3 = outer
+
+    inner1 = Collection(g, inner1)
+    inner1_1, inner1_2 = map(lambda l: Collection(g, l), inner1)
+    assert list(inner1_1) == [Literal(x) for x in (1, 2, 3)]
+    assert list(inner1_2) == [Literal(x) for x in ("4", 5)]
+
+    assert inner2 == Literal(6)
+
+    inner3 = Collection(g, inner3)
+    assert list(inner3) == [Literal(7), res]
+
+
+def test_no_container():
+    g = Graph()
+    g.parse(data=data_no_container, format="application/ld+json")
+
+    assert len(g) == 8
+
+    objects = set(g.objects(predicate=prop))
+    assert len(objects) == 8
+    assert objects == set([Literal(x) for x in (1, 2, 3, "4", 5, 6, 7)] + [res])