fix: narrow the context identifier type from Node to IdentifiedNode

Narrow the context identifier type from `Node` to `IdentifiedNode` as
`Node` is too broad and no supported format (N3, RDF) allows using
anything other than `IdentifiedNode` as context identifiers.

The only change here that has a runtime impact is the change in
`Graph.__init__` to check isinstance against `Node` instead
of `IdentifiedNode`.

CHANGELOG.md

@@ -159,6 +159,24 @@ and will be removed for release.
 <!-- -->
 <!-- -->
 
+
+<!-- -->
+<!-- -->
+<!-- CHANGE BARRIER: START PR #2069 -->
+<!-- -->
+<!-- -->
+
+- Narrow the type of context-identifiers/graph-names from `rdflib.term.Node` to
+  `rdflib.term.IdentifiedNode` as no supported abstract syntax allows for other
+  types of context-identifiers.
+  [PR #2069](https://github.com/RDFLib/rdflib/pull/2069).
+
+<!-- -->
+<!-- -->
+<!-- CHANGE BARRIER: END PR #2069 -->
+<!-- -->
+<!-- -->
+
 <!-- -->
 <!-- -->
 <!-- CHANGE BARRIER: START -->

rdflib/graph.py

@@ -42,7 +42,7 @@
 _SubjectType = Node
 _PredicateType = Node
 _ObjectType = Node
-_ContextIdentifierType = Node
+_ContextIdentifierType = IdentifiedNode
 
 _TripleType = Tuple["_SubjectType", "_PredicateType", "_ObjectType"]
 _QuadType = Tuple["_SubjectType", "_PredicateType", "_ObjectType", "_ContextType"]
@@ -373,9 +373,9 @@ def __init__(
     ):
         super(Graph, self).__init__()
         self.base = base
-        self.__identifier: Node
+        self.__identifier: _ContextIdentifierType
         self.__identifier = identifier or BNode()  # type: ignore[assignment]
-        if not isinstance(self.__identifier, Node):
+        if not isinstance(self.__identifier, IdentifiedNode):
             self.__identifier = URIRef(self.__identifier)  # type: ignore[unreachable]
         self.__store: Store
         if not isinstance(store, Store):

rdflib/plugins/stores/auditable.py

@@ -79,9 +79,8 @@ def add(
         lock = destructiveOpLocks["add"]
         lock = lock if lock else threading.RLock()
         with lock:
-            # type error: Argument 2 to "Graph" has incompatible type "Node"; expected "Union[IdentifiedNode, str, None]"
             context = (
-                context.__class__(self.store, context.identifier)  # type: ignore[arg-type]
+                context.__class__(self.store, context.identifier)
                 if context is not None
                 else None
             )
@@ -104,9 +103,8 @@ def remove(
         with lock:
             # Need to determine which quads will be removed if any term is a
             # wildcard
-            # type error: error: Argument 2 to "Graph" has incompatible type "Node"; expected "Union[IdentifiedNode, str, None]"
             context = (
-                context.__class__(self.store, context.identifier)  # type: ignore[arg-type]
+                context.__class__(self.store, context.identifier)
                 if context is not None
                 else None
             )
@@ -144,19 +142,17 @@ def triples(
         self, triple: "_TriplePatternType", context: Optional["_ContextType"] = None
     ) -> Iterator[Tuple["_TripleType", Iterator[Optional["_ContextType"]]]]:
         (su, pr, ob) = triple
-        # type error: Argument 2 to "Graph" has incompatible type "Node"; expected "Union[IdentifiedNode, str, None]"
         context = (
-            context.__class__(self.store, context.identifier)  # type: ignore[arg-type]
+            context.__class__(self.store, context.identifier)
             if context is not None
             else None
         )
         for (s, p, o), cg in self.store.triples((su, pr, ob), context):
             yield (s, p, o), cg
 
     def __len__(self, context: Optional["_ContextType"] = None):
-        # type error: Argument 2 to "Graph" has incompatible type "Node"; expected "Union[IdentifiedNode, str, None]"
         context = (
-            context.__class__(self.store, context.identifier)  # type: ignore[arg-type]
+            context.__class__(self.store, context.identifier)
             if context is not None
             else None
         )
@@ -194,9 +190,8 @@ def rollback(self) -> None:
                         (subject, predicate, obj), Graph(self.store, context)  # type: ignore[arg-type]
                     )
                 else:
-                    # type error: Argument 2 to "Graph" has incompatible type "Optional[Node]"; expected "Union[IdentifiedNode, str, None]"
                     self.store.remove(
-                        (subject, predicate, obj), Graph(self.store, context)  # type: ignore[arg-type]
+                        (subject, predicate, obj), Graph(self.store, context)
                     )
 
             self.reverseOps = []

test/utils/__init__.py

@@ -223,8 +223,7 @@ def quad_set(
                 gn_id = gn  # type: ignore[unreachable]
             elif isinstance(graph, ConjunctiveGraph):
                 assert isinstance(gn, Graph)
-                # type error: Incompatible types in assignment (expression has type "Node", variable has type "Identifier")
-                gn_id = gn.identifier  # type: ignore[assignment]
+                gn_id = gn.identifier
             else:
                 raise ValueError(f"invalid graph type {type(graph)}: {graph!r}")
             s, p, o = cls.nodes((sn, pn, on), bnode_handling)