A bug was added with the `seek_into_the_danger_zone()` optimization
(Spotted and fixed by Stu)
The contract says seek_into_the_danger_zone returns true if do is part of the docset.
The blanket implementation goes like this.
```
let current_doc = self.doc();
if current_doc < target {
self.seek(target);
}
self.doc() == target
```
So it will return true if target is TERMINATED, where really TERMINATED does not belong to the docset.
The fix tries to clarify the contracts and fixes the intersection algorithm.
We observe a small but all over the board improvement in intersection performance.
---------
Co-authored-by: Stu Hood <stuhood@gmail.com>
Co-authored-by: Paul Masurel <paul.masurel@datadoghq.com>
- Change in the DocSet and Scorer API. (@fulmicoton).
A freshly created DocSet point directly to their first doc. A sentinel value called TERMINATED marks the end of a DocSet.
`.advance()` returns the new DocId. `Scorer::skip(target)` has been replaced by `Scorer::seek(target)` and returns the resulting DocId.
As a result, iterating through DocSet now looks as follows
```rust
let mut doc = docset.doc();
while doc != TERMINATED {
// ...
doc = docset.advance();
}
```
The change made it possible to greatly simplify a lot of the docset's code.
- Misc internal optimization and introduction of the `Scorer::for_each_pruning` function. (@fulmicoton)
