Different hashCodes produced for classes with List properties

[georgepapas]

Describe the bug
When a class extends Equatable and that class has a list property, two different instances, with the exact same properties, produce different hashCode values.

To Reproduce

class Foo extends Equatable {
  String foo;
  String bar;
  List<String> list;

  Foo(this.foo, this.bar, this.list) : super([foo, bar, list]);
}

void main() {
  group("hashCode test", () {
    test("foo", () {
      expect(Foo('aaa', 'bbb', []).hashCode, equals(Foo('aaa', 'bbb', []).hashCode));
    });
  });
}

Expected behavior
expected the same hashCode to be produced

Version
0.2.1

[felangel]

@georgepapas thanks for reporting this! I'm pushing a fix for it now in #9 👍

[felangel]

@georgepapas this should now be fixed in equatable v0.2.2. Thanks again for catching and reporting this! 💯

[georgepapas]

Thanks for that, that was quick!, I'll take a look. Just one thing about the change, I ended up using something like this locally as a temporary workaround

DeepCollectionEquality.unordered().equals(my_list, other.my_list);

Does the fix in the commit introduce potential for stack overflow error if you have a list with items that reference the list?

Cheers

[felangel]

@georgepapas thanks! Hmm can you provide an example? 🤔

[georgepapas]

Hey @felangel . Sorry for the late reply... Try this...

class Child extends Equatable {
  Parent parent;
  Child(this.parent) : super([parent]);
}

class Parent extends Equatable {
  List<Child> children;
  Parent(List<Child> children) : super([children]);

  void addChild(Child child) {
    children.add(child);
  }
}

void main() {
  Parent parent;

  setUp(() {
    List<Child> children = [];
    parent = Parent(children);

    children.add(Child(parent));
    children.add(Child(parent));

  });

  test("biderectional relationships cause stack overflow", () {
    parent.hashCode;
  });
}