Panic occurs when search with + and - query

[Leonqn]

Describe the bug
Code below panics with thread 'main' panicked at 'assertion failed: target >= self.doc()', but if you run this code with range 0..193 there will be no panic.

Which version of tantivy are you using?
0.7.1

To Reproduce

use tantivy::Index;
use tantivy::schema::*;
use tantivy::collector::TopCollector;
use tantivy::query::QueryParser;

pub fn main() {
    let mut schema_builder = SchemaBuilder::new();
    let test_field = schema_builder.add_text_field("test", STRING);
    let index = Index::create_in_ram(schema_builder.build());

    let mut index_writer = index.writer(3000000).unwrap();

    for i in 0..194 {
        let mut doc = Document::new();
        if i % 3 == 0 {
            doc.add_text(test_field, "f");
        } else {
            doc.add_text(test_field, "m");
        }

        index_writer.add_document(doc);
    }
    index_writer.commit().unwrap();

    index.load_searchers().unwrap();

    let searcher = index.searcher();

    let query_parser = QueryParser::for_index(&index, vec![test_field]);
    let query = query_parser.parse_query("-m +f").unwrap();

    let mut collector = TopCollector::with_limit(1);
    searcher.search(&*query, &mut collector).unwrap();

    println!("{}", collector.docs().len())
}

[fulmicoton]

Thank you for the great bug report. (That sounds terrible though) @Leonqn

I'll have a look as soon as possible and publish a fix as a 0.7.2

[fulmicoton]

I confirm I can reproduce. The bug is in the TermScorer itself.

[fulmicoton]

I'll publish the fix today

[fulmicoton]

This bug happens "fairly often".

If you have a product running with tantivy in release without debug_assert, no sweat, the result are actually correct. The debug_assert itself is not useful anymore.

[fulmicoton]

Published fix in tantivy 0.7.2. Yanking tantivy 0.7.1.