Add __hash__ method to Node

tests/test_tree_sitter.py

@@ -1622,6 +1622,33 @@ def test_point_range_captures(self):
         self.assertEqual(captures[1][0].end_point, (1, 5))
         self.assertEqual(captures[1][1], "func-call")
 
+    def test_node_hash(self):
+        parser = Parser()
+        parser.set_language(PYTHON)
+        source_code = b"def foo():\n  bar()\n  bar()"
+        tree = parser.parse(source_code)
+        root_node = tree.root_node
+        first_function_node = root_node.children[0]
+        second_function_node = root_node.children[0]
+
+        # Uniqueness and consistency
+        self.assertEqual(hash(first_function_node), hash(first_function_node))
+        self.assertNotEqual(hash(root_node), hash(first_function_node))
+
+        # Equality implication
+        self.assertEqual(hash(first_function_node), hash(second_function_node))
+        self.assertTrue(first_function_node == second_function_node)
+
+        # Different nodes with different properties
+        different_tree = parser.parse(b"def baz():\n  qux()")
+        different_node = different_tree.root_node.children[0]
+        self.assertNotEqual(hash(first_function_node), hash(different_node))
+
+        # Same code, different parse trees
+        another_tree = parser.parse(source_code)
+        another_node = another_tree.root_node.children[0]
+        self.assertNotEqual(hash(first_function_node), hash(another_node))
+
 
 class TestLookaheadIterator(TestCase):
     def test_lookahead_iterator(self):

tree_sitter/binding.c

@@ -690,6 +690,18 @@ static PyObject *node_get_text(Node *self, void *payload) {
     return result;
 }
 
+static Py_hash_t node_hash(Node *self) {
+    ModuleState *state = PyType_GetModuleState(Py_TYPE(self));
+
+    // __eq__ and __hash__ must be compatible. As __eq__ is defined by
+    // ts_node_eq, which in turn checks the tree pointer and the node
+    // id, we can use those values to compute the hash.
+    Py_hash_t tree_hash = _Py_HashPointer(self->node.tree);
+    Py_hash_t id_hash = (Py_hash_t)(self->node.id);
+
+    return tree_hash ^ id_hash;
+}
+
 static PyMethodDef node_methods[] = {
     {
         .ml_name = "walk",
@@ -839,6 +851,7 @@ static PyType_Slot node_type_slots[] = {
     {Py_tp_dealloc, node_dealloc},
     {Py_tp_repr, node_repr},
     {Py_tp_richcompare, node_compare},
+    {Py_tp_hash, node_hash},
     {Py_tp_methods, node_methods},
     {Py_tp_getset, node_accessors},
     {0, NULL},