<array>.__owl__.parent sometimes refers to the non-observed version of the parent about owl

[ged-odoo]

@alexkuhn could you elaborate?

[alexkuhn]

Have some crashes because of this, I'm still investigating the issue and will provide short code to reproduce the issue.

[alexkuhn]

FYI, following LOC makes it crash with observed array item:
https://github.com/odoo/owl/blob/master/src/observer.ts#L28
It happens after the parent is assigned to another object.

[ged-odoo]

i have a failing test case:

  test("properly handle swapping elements", () => {
    const observer = new Observer();
    const obj: any = { a: { arr: [] }, b: 1 };
    observer.observe(obj);

    // swap a and b
    const b = obj.b;
    obj.b = obj.a;
    obj.a = b;
    expect(observer.rev).toBe(3);

    // push something into array to make sure it works
    obj.b.arr.push("blanche");
    expect(observer.rev).toBe(4);
  });

However, the issue is slightly trickier than I expected. This happens because we unobserve old values when reassigning. It is not hard to make this work for usual situations, but handling cycles in the state is tricky. Not sure yet what to do

[ged-odoo]

i have a failing test case:

  test("properly handle swapping elements", () => {
    const observer = new Observer();
    const obj: any = { a: { arr: [] }, b: 1 };
    observer.observe(obj);

    // swap a and b
    const b = obj.b;
    obj.b = obj.a;
    obj.a = b;
    expect(observer.rev).toBe(3);

    // push something into array to make sure it works
    obj.b.arr.push("blanche");
    expect(observer.rev).toBe(4);
  });

However, the issue is slightly trickier than I expected. This happens because we unobserve old values when reassigning. It is not hard to make this work for usual situations, but handling cycles in the state is tricky. Not sure yet what to do

[alexkuhn]

Shorter test that shows the issue:

test("properly handle assigning observed obj containing array", () => {
    const observer = new Observer();
    const obj: any = { a: { arr: [], val: 'test' } };
    observer.observe(obj);

    obj.a = { ...obj.a, val: 'test2' };
    expect(observer.rev).toBe(2);

    // push something into array to make sure it works
    obj.a.arr.push("blanche");
    expect(observer.rev).toBe(3);
  });