Allow some custom return types to be annotated as generic classes at runtime

rustworkx/rustworkx.pyi

@@ -1074,6 +1074,8 @@ class _RustworkxCustomVecIter(Generic[_T_co], Sequence[_T_co], ABC):
     def __getitem__(self, index: int) -> _T_co: ...
     @overload
     def __getitem__(self: Self, index: slice) -> Self: ...
+    @classmethod
+    def __class_getitem__(cls, key: Any, /) -> GenericAlias: ...
     def __getstate__(self) -> Any: ...
     def __hash__(self) -> int: ...
     def __len__(self) -> int: ...
@@ -1091,6 +1093,8 @@ class _RustworkxCustomHashMapIter(Generic[_S, _T_co], Mapping[_S, _T_co], ABC):
     def __contains__(self, other: object) -> bool: ...
     def __eq__(self, other: object) -> bool: ...
     def __getitem__(self, index: _S) -> _T_co: ...
+    @classmethod
+    def __class_getitem__(cls, key: Any, /) -> GenericAlias: ...
     def __getstate__(self) -> Any: ...
     def __hash__(self) -> int: ...
     def __iter__(self) -> Iterator[_S]: ...

src/iterators.rs

@@ -41,12 +41,15 @@
 use std::collections::hash_map::DefaultHasher;
 use std::hash::Hasher;
 
+use super::generic_class_getitem;
 use num_bigint::BigUint;
 use rustworkx_core::dictmap::*;
 
 use ndarray::prelude::*;
 use numpy::IntoPyArray;
-use pyo3::exceptions::{PyIndexError, PyKeyError, PyNotImplementedError, PyValueError};
+use pyo3::exceptions::{
+    PyIndexError, PyKeyError, PyNotImplementedError, PyTypeError, PyValueError,
+};
 use pyo3::gc::PyVisit;
 use pyo3::prelude::*;
 use pyo3::types::IntoPyDict;
@@ -618,6 +621,24 @@ macro_rules! custom_vec_iter_impl {
                 }
             }
 
+            #[classmethod]
+            #[pyo3(signature = (key, /))]
+            pub fn __class_getitem__(
+                cls: &Bound<'_, pyo3::types::PyType>,
+                key: &Bound<'_, PyAny>,
+            ) -> PyResult<PyObject> {
+                let class_string = stringify!($name);
+                const ALLOWED_GENERIC_CLASSES: [&str; 3] =
+                    ["BFSSuccessors", "BFSPredecessors", "WeightedEdgeList"];
+                if !ALLOWED_GENERIC_CLASSES.contains(&class_string) {
+                    return Err(PyTypeError::new_err(format!(
+                        "type 'rustworkx.{}' is not subscriptable",
+                        class_string
+                    )));
+                }
+                generic_class_getitem(cls, key)
+            }
+
             #[pyo3(signature = (dtype=None, copy=None))]
             fn __array__(
                 &self,
@@ -1290,6 +1311,23 @@ macro_rules! custom_hash_map_iter_impl {
                 }
             }
 
+            #[classmethod]
+            #[pyo3(signature = (key, /))]
+            pub fn __class_getitem__(
+                cls: &Bound<'_, pyo3::types::PyType>,
+                key: &Bound<'_, PyAny>,
+            ) -> PyResult<PyObject> {
+                let class_string = stringify!($name);
+                const ALLOWED_GENERIC_CLASSES: [&str; 1] = ["EdgeIndexMap"];
+                if !ALLOWED_GENERIC_CLASSES.contains(&class_string) {
+                    return Err(PyTypeError::new_err(format!(
+                        "type 'rustworkx.{}' is not subscriptable",
+                        class_string
+                    )));
+                }
+                generic_class_getitem(cls, key)
+            }
+
             fn __iter__(slf: PyRef<Self>) -> $nameKeys {
                 $nameKeys {
                     $keys: slf.$data.keys().copied().collect(),

tests/test_annotations.py

@@ -14,6 +14,7 @@
 import types
 import unittest
 
+from typing import Optional
 
 class TestAnnotationSubscriptions(unittest.TestCase):
     def test_digraph(self):
@@ -36,3 +37,39 @@ def test_dag(self):
             graph.__class_getitem__((int, int)),
             types.GenericAlias,
         )
+
+    def test_custom_vector_allowed(self):
+        graph: rx.PyGraph[Optional[int], Optional[int]] = rx.generators.path_graph(5)
+        we_list: rx.WeightedEdgeList[Optional[int]] = graph.weighted_edge_list()
+        self.assertIsInstance(
+            we_list.__class_getitem__((Optional[int],)),
+            types.GenericAlias,
+        )
+
+    def test_custom_vector_not_allowed(self):
+        graph: rx.PyGraph[Optional[int], Optional[int]] = rx.generators.path_graph(5)
+        edge_list: rx.EdgeList = graph.edge_list()
+        with self.assertRaises(TypeError):
+            self.assertIsInstance(
+                edge_list.__class_getitem__((Optional[int],)),
+                types.GenericAlias,
+            )
+
+    def test_custom_hashmap_allowed(self):
+        graph: rx.PyGraph[Optional[int], Optional[int]] = rx.generators.path_graph(5)
+        ei_map: rx.WeightedEdgeList[Optional[int]] = graph.edge_index_map()
+        self.assertIsInstance(
+            ei_map.__class_getitem__((Optional[int],)),
+            types.GenericAlias,
+        )
+
+    def test_custom_hashmap_not_allowed(self):
+        graph: rx.PyGraph[Optional[int], Optional[int]] = rx.generators.path_graph(5)
+        all_pairs_pm: rx.AllPairsPathMapping = rx.all_pairs_dijkstra_shortest_paths(
+            graph, lambda _: 1.0
+        )
+        with self.assertRaises(TypeError):
+            self.assertIsInstance(
+                all_pairs_pm.__class_getitem__((Optional[int],)),
+                types.GenericAlias,
+            )