delete_vertices does not work on subclassed graph #496
Description
Describe the bug
I have subclassed Graph and added a custom __init__ method by:
- Creating an instance of the subclassed Graph
- Calling
igraph.Graph.__init__ - Merging the existing graph into the new one
but this apparently fails when trying to delete vertices. The edge set is not updated properly. In the test, the graph is:
0 -> 0
1 -> 1
and the first edge has prop set to a while the second edge has prop set to b. Now, if I delete the first vertex, it would be expected that graph.es['prop'] returns b, but it returns a in the subclass case.
Fwiw, delete_vertices deals with vertex properties correctly and delete_edges seems to work fine as well.
To reproduce
Test case:
import unittest
from igraph import Graph
class TestSubclass(Graph):
@staticmethod
def __new__(cls, graph=None, *args, **kwargs):
instance = super().__new__(cls, directed=True, *args, **kwargs)
super().__init__(instance, directed=True, *args, **kwargs)
if graph is not None:
instance = instance.union(graph)
return instance
def __init__(self, graph=None, *args, **kwargs) -> None:
pass
class SubclassTest(unittest.TestCase):
def test_deleteVertices_igraph(self) -> None:
graph = Graph(2, [(0, 0), (1, 1)], directed=True)
graph.es['prop'] = ["a", "b"]
graph.delete_vertices({1})
self.assertEqual(["a"], graph.es['prop'])
def test_deleteVertices_subclass(self) -> None:
graph = Graph(2, [(0, 0), (1, 1)], directed=True)
automaton = TestSubclass(graph)
automaton.es['prop'] = ["a", "b"]
automaton.delete_vertices({1})
self.assertEqual(["a"], automaton.es['prop'])
def test_incident_igraph(self) -> None:
graph = Graph(4, [(0, 0), (1, 1), (2, 2), (3, 3)], directed=True)
graph.es['prop'] = ["a", "b", "c", "d"]
self.assertEqual(["a"], graph.es(_incident=[0])['prop'])
def test_incident_subclass(self) -> None:
graph = Graph(4, [(0, 0), (1, 1), (2, 2), (3, 3)], directed=True)
automaton = TestSubclass(graph)
automaton.es['prop'] = ["a", "b", "c", "d"]
self.assertEqual(["a"], automaton.es(_incident=[0])['prop'])
def test_deleteVertices_subclass_deleteEdge(self) -> None:
graph = Graph(2, [(0, 0), (1, 1)], directed=True)
automaton = TestSubclass(graph)
automaton.es['prop'] = ["a", "b"]
automaton.delete_edges({1})
self.assertEqual(["a"], automaton.es['prop'])
def test_deleteVertices_subclass_vertexSet(self) -> None:
graph = Graph(2, [(0, 0), (1, 1)], directed=True)
automaton = TestSubclass(graph)
automaton.vs['prop'] = ["c", "d"]
automaton.delete_vertices({1})
self.assertEqual(["c"], automaton.vs['prop'])Version information
igraph 0.9.8 on Python 3.9, also tested on igraph 0.9.1