thread 'some_test' panicked at '`execute` method for field `MyValT::md` invoked', about salsa HOT 2 OPEN

@enomado I believe the panic is the expected behavior of Salsa, as mentioned in issue #407. The issue lies in the code p.md(&db) within the loop, which continues to use a tracked struct after altering the inputs using a.set_md(&mut db).to(vec![i as f64]). To fix this, you should call m_merge again to get the newest tracked struct.

let a = MyVal::new(&db, vec![1.0]);
let b = MyVal::new(&db, vec![2.0]);

let p = m_merge(&db, a, b);

for i in 0..10 {
    a.set_md(&mut db).to(vec![i as f64]);
    let p = m_merge(&db, a, b);
    dbg!(p.md(&db));
}

However, I think that the error message needs improvement to avoid confusion. A panic message like "accessing a field of a tracked struct MyVal from an older revision" would be better.

from salsa.

@xffxff thanks! I thought tracked structure can store whole computation chain at its own. I think it must be covered in documentation. just like

dont expect tracked struct can recalculate itself without calling whole chain

it could clarify a lot :)

Btw, please, tell where I wrong. I want generalize input structs and tracked structs

from salsa.