[DO NOT REVIEW] Add a bunch of typing

This is a branch I'm maintaing with a bunch of typing, I'm planning to
integrate it with master in parts, anyone is welcome to have a look but
most of what is happening here is subject to change.

Taskfile.yml

@@ -108,11 +108,17 @@ tasks:
       - "{{._PYTHON}} -m isort --check --diff ."
       - "{{._PYTHON}} -m black --check --diff ."
 
+  typecheck:
+    desc: Check type hints
+    cmds:
+      - "{{._PYTHON}} -m mypy --show-error-context --show-error-codes"
+
+
   validate:static:
     desc: Perform static validation
     cmds:
       - task: lint
-      - "{{._PYTHON}} -m mypy --show-error-context --show-error-codes"
+      - task: typecheck
 
   validate:fix:
     desc: Fix auto-fixable validation errors.

rdflib/__init__.py

@@ -84,6 +84,7 @@
     "VOID",
     "XSD",
     "util",
+    "_typing",
 ]
 
 import logging
@@ -194,5 +195,5 @@
 assert plugin
 assert query
 
-from rdflib import util
+from rdflib import _typing, util
 from rdflib.container import *

rdflib/_typing.py

@@ -0,0 +1,23 @@
+# import sys
+# from typing import TYPE_CHECKING, Optional, Tuple, TypeVar
+
+# if sys.version_info >= (3, 10):
+#     from typing import TypeAlias
+# else:
+#     from typing_extensions import TypeAlias
+
+# if TYPE_CHECKING:
+#     from rdflib.graph import Graph
+#     from rdflib.term import IdentifiedNode, Identifier
+
+# _SubjectType: TypeAlias = "IdentifiedNode"
+# _PredicateType: TypeAlias = "IdentifiedNode"
+# _ObjectType: TypeAlias = "Identifier"
+
+# _TripleType = Tuple["_SubjectType", "_PredicateType", "_ObjectType"]
+# _QuadType = Tuple["_SubjectType", "_PredicateType", "_ObjectType", "Graph"]
+# _TriplePatternType = Tuple[
+#     Optional["_SubjectType"], Optional["_PredicateType"], Optional["_ObjectType"]
+# ]
+
+# _GraphT = TypeVar("_GraphT", bound="Graph")

rdflib/compare.py

@@ -104,7 +104,7 @@
     Union,
 )
 
-from rdflib.graph import ConjunctiveGraph, Graph, ReadOnlyGraphAggregate
+from rdflib.graph import ConjunctiveGraph, Graph, ReadOnlyGraphAggregate, _TripleType
 from rdflib.term import BNode, IdentifiedNode, Node, URIRef
 
 if TYPE_CHECKING:
@@ -281,7 +281,6 @@ def copy(self):
         )
 
 
-_TripleT = List[Node]
 _HashT = Callable[[], "HASH"]
 
 
@@ -326,7 +325,9 @@ def _initial_color(self) -> List[Color]:
                     self._neighbors[p].add(p)
         if len(bnodes) > 0:
             return [Color(list(bnodes), self.hashfunc, hash_cache=self._hash_cache)] + [
-                Color([x], self.hashfunc, x, hash_cache=self._hash_cache)
+                # type error: List item 0 has incompatible type "Union[IdentifiedNode, Literal]"; expected "IdentifiedNode"
+                # type error: Argument 3 to "Color" has incompatible type "Union[IdentifiedNode, Literal]"; expected "Tuple[Tuple[Union[int, str], URIRef, Union[int, str]], ...]"
+                Color([x], self.hashfunc, x, hash_cache=self._hash_cache)  # type: ignore[list-item, arg-type]
                 for x in others
             ]
         else:
@@ -521,7 +522,7 @@ def canonical_triples(self, stats: Optional[Stats] = None):
 
     def _canonicalize_bnodes(
         self,
-        triple: Tuple[IdentifiedNode, IdentifiedNode, Node],
+        triple: "_TripleType",
         labels: Dict[Node, str],
     ):
         for term in triple:
@@ -531,7 +532,7 @@ def _canonicalize_bnodes(
                 yield term
 
 
-def to_isomorphic(graph):
+def to_isomorphic(graph: Graph) -> IsomorphicGraph:
     if isinstance(graph, IsomorphicGraph):
         return graph
     result = IsomorphicGraph()
@@ -541,7 +542,7 @@ def to_isomorphic(graph):
     return result
 
 
-def isomorphic(graph1, graph2):
+def isomorphic(graph1: Graph, graph2: Graph) -> bool:
     """Compare graph for equality.
 
     Uses an algorithm to compute unique hashes which takes bnodes into account.
@@ -577,7 +578,9 @@ def isomorphic(graph1, graph2):
     return gd1 == gd2
 
 
-def to_canonical_graph(g1, stats=None):
+def to_canonical_graph(
+    g1: Graph, stats: Optional[Stats] = None
+) -> ReadOnlyGraphAggregate:
     """Creates a canonical, read-only graph.
 
     Creates a canonical, read-only graph where all bnode id:s are based on
@@ -588,7 +591,7 @@ def to_canonical_graph(g1, stats=None):
     return ReadOnlyGraphAggregate([graph])
 
 
-def graph_diff(g1, g2):
+def graph_diff(g1: Graph, g2: Graph) -> Tuple[Graph, Graph, Graph]:
     """Returns three sets of triples: "in both", "in first" and "in second"."""
     # bnodes have deterministic values in canonical graphs:
     cg1 = to_canonical_graph(g1)
@@ -602,7 +605,7 @@ def graph_diff(g1, g2):
 _MOCK_BNODE = BNode()
 
 
-def similar(g1, g2):
+def similar(g1: Graph, g2: Graph):
     """Checks if the two graphs are "similar".
 
     Checks if the two graphs are "similar", by comparing sorted triples where
@@ -615,12 +618,12 @@ def similar(g1, g2):
     return all(t1 == t2 for (t1, t2) in _squashed_graphs_triples(g1, g2))
 
 
-def _squashed_graphs_triples(g1, g2):
+def _squashed_graphs_triples(g1: Graph, g2: Graph):
     for (t1, t2) in zip(sorted(_squash_graph(g1)), sorted(_squash_graph(g2))):
         yield t1, t2
 
 
-def _squash_graph(graph):
+def _squash_graph(graph: Graph):
     return (_squash_bnodes(triple) for triple in graph)
 
 

rdflib/extras/external_graph_libs.py

@@ -13,6 +13,9 @@
 """
 
 import logging
+from typing import Any, Dict, List
+
+from rdflib.graph import Graph
 
 logger = logging.getLogger(__name__)
 
@@ -22,9 +25,9 @@ def _identity(x):
 
 
 def _rdflib_to_networkx_graph(
-    graph,
+    graph: Graph,
     nxgraph,
-    calc_weights,
+    calc_weights: bool,
     edge_attrs,
     transform_s=_identity,
     transform_o=_identity,
@@ -70,7 +73,7 @@ def _rdflib_to_networkx_graph(
 
 
 def rdflib_to_networkx_multidigraph(
-    graph, edge_attrs=lambda s, p, o: {"key": p}, **kwds
+    graph: Graph, edge_attrs=lambda s, p, o: {"key": p}, **kwds
 ):
     """Converts the given graph into a networkx.MultiDiGraph.
 
@@ -124,8 +127,8 @@ def rdflib_to_networkx_multidigraph(
 
 
 def rdflib_to_networkx_digraph(
-    graph,
-    calc_weights=True,
+    graph: Graph,
+    calc_weights: bool = True,
     edge_attrs=lambda s, p, o: {"triples": [(s, p, o)]},
     **kwds,
 ):
@@ -187,8 +190,8 @@ def rdflib_to_networkx_digraph(
 
 
 def rdflib_to_networkx_graph(
-    graph,
-    calc_weights=True,
+    graph: Graph,
+    calc_weights: bool = True,
     edge_attrs=lambda s, p, o: {"triples": [(s, p, o)]},
     **kwds,
 ):
@@ -250,9 +253,9 @@ def rdflib_to_networkx_graph(
 
 
 def rdflib_to_graphtool(
-    graph,
-    v_prop_names=[str("term")],
-    e_prop_names=[str("term")],
+    graph: Graph,
+    v_prop_names: List[str] = [str("term")],
+    e_prop_names: List[str] = [str("term")],
     transform_s=lambda s, p, o: {str("term"): s},
     transform_p=lambda s, p, o: {str("term"): p},
     transform_o=lambda s, p, o: {str("term"): o},
@@ -313,7 +316,8 @@ def rdflib_to_graphtool(
     True
 
     """
-    import graph_tool as gt
+    # pytype error: Can't find module 'graph_tool'.
+    import graph_tool as gt  # pytype: disable=import-error
 
     g = gt.Graph()
 
@@ -323,7 +327,7 @@ def rdflib_to_graphtool(
     eprops = [(epn, g.new_edge_property("object")) for epn in e_prop_names]
     for epn, eprop in eprops:
         g.edge_properties[epn] = eprop
-    node_to_vertex = {}
+    node_to_vertex: Dict[Any, Any] = {}
     for s, p, o in graph:
         sv = node_to_vertex.get(s)
         if sv is None:

rdflib/extras/infixowl.py

@@ -111,11 +111,10 @@
 import itertools
 import logging
 
-from rdflib import RDF, RDFS, BNode, Literal, Namespace, URIRef, Variable
 from rdflib.collection import Collection
 from rdflib.graph import Graph
-from rdflib.namespace import OWL, XSD, NamespaceManager
-from rdflib.term import Identifier
+from rdflib.namespace import OWL, RDF, RDFS, XSD, Namespace, NamespaceManager
+from rdflib.term import BNode, Identifier, Literal, URIRef, Variable
 from rdflib.util import first
 
 logger = logging.getLogger(__name__)