revset: don't rewrite '~set & filter' as difference

Since filter is slow in general, its input set should be minimized. This has
measurable impact on artificial query like '~(v0.4.0..) & author(_)'. If it
were evaluated as a difference of sets, all commits would have to be loaded.
This commit is contained in:
Yuya Nishihara 2023-04-03 12:33:25 +09:00
parent 707d82245f
commit 0bfdbcaa1e

View file

@ -1380,6 +1380,8 @@ fn fold_difference(expression: &Rc<RevsetExpression>) -> TransformedExpression {
transform_expression_bottom_up(expression, |expression| match expression.as_ref() {
RevsetExpression::Intersection(expression1, expression2) => {
match (expression1.as_ref(), expression2.as_ref()) {
// For '~x & f', don't move filter node 'f' left
(_, RevsetExpression::Filter(_) | RevsetExpression::AsFilter(_)) => None,
(_, RevsetExpression::NotIn(complement)) => {
Some(to_difference(expression1, complement))
}
@ -2490,13 +2492,11 @@ mod tests {
);
assert_eq!(
optimize(parse("present(author(foo) ~ bar)").unwrap()),
Rc::new(RevsetExpression::AsFilter(Rc::new(
RevsetExpression::Present(
RevsetExpression::filter(RevsetFilterPredicate::Author("foo".to_owned()))
optimize(parse("present(foo ~ bar)").unwrap()),
Rc::new(RevsetExpression::Present(
RevsetExpression::symbol("foo".to_owned())
.minus(&RevsetExpression::symbol("bar".to_owned()))
)
)))
))
);
assert_eq!(
optimize(parse("present(branches() & all())").unwrap()),
@ -2766,7 +2766,63 @@ mod tests {
),
),
)
"###)
"###);
// '~set & filter()' shouldn't be substituted.
insta::assert_debug_snapshot!(
optimize(parse("~foo & author(bar)").unwrap()), @r###"
Intersection(
NotIn(
Symbol(
"foo",
),
),
Filter(
Author(
"bar",
),
),
)
"###);
insta::assert_debug_snapshot!(
optimize(parse("~foo & (author(bar) | baz)").unwrap()), @r###"
Intersection(
NotIn(
Symbol(
"foo",
),
),
AsFilter(
Union(
Filter(
Author(
"bar",
),
),
Symbol(
"baz",
),
),
),
)
"###);
// Filter should be moved right of the intersection.
insta::assert_debug_snapshot!(
optimize(parse("author(foo) ~ bar").unwrap()), @r###"
Intersection(
NotIn(
Symbol(
"bar",
),
),
Filter(
Author(
"foo",
),
),
)
"###);
}
#[test]