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revset: add substitution rule for roots..heads

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While working on ancestor generation, I noticed Mercurial has this
substitution rule. Since it's easier to deal with Ancestors() than Range {},
'roots..heads' is first decomposed to ':heads & ~:roots'.
This commit is contained in:
Yuya Nishihara 2022-12-11 20:25:40 +09:00
parent e6229e6d77
commit 29a565e3fb
1 changed files with 66 additions and 2 deletions
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68
lib/src/revset.rs
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@ -1262,11 +1262,31 @@ fn fold_redundant_expression(expression: &Rc<RevsetExpression>) -> Option<Rc<Rev
/// Transforms negative intersection to difference. Redundant intersections like
/// `all() & e` should have been removed.
fn fold_difference(expression: &Rc<RevsetExpression>) -> Option<Rc<RevsetExpression>> {
fn to_difference(
expression: &Rc<RevsetExpression>,
complement: &Rc<RevsetExpression>,
) -> Rc<RevsetExpression> {
match (expression.as_ref(), complement.as_ref()) {
// :heads & ~(:roots) -> roots..heads
(RevsetExpression::Ancestors(heads), RevsetExpression::Ancestors(roots)) => {
Rc::new(RevsetExpression::Range {
roots: roots.clone(),
heads: heads.clone(),
})
}
_ => expression.minus(complement),
}
}
transform_expression_bottom_up(expression, |expression| match expression.as_ref() {
RevsetExpression::Intersection(expression1, expression2) => {
match (expression1.as_ref(), expression2.as_ref()) {
(_, RevsetExpression::NotIn(complement)) => Some(expression1.minus(complement)),
(RevsetExpression::NotIn(complement), _) => Some(expression2.minus(complement)),
(_, RevsetExpression::NotIn(complement)) => {
Some(to_difference(expression1, complement))
}
(RevsetExpression::NotIn(complement), _) => {
Some(to_difference(expression2, complement))
}
_ => None,
}
}
@ -1280,6 +1300,10 @@ fn fold_difference(expression: &Rc<RevsetExpression>) -> Option<Rc<RevsetExpress
/// further by `fold_redundant_expression()`.
fn unfold_difference(expression: &Rc<RevsetExpression>) -> Option<Rc<RevsetExpression>> {
transform_expression_bottom_up(expression, |expression| match expression.as_ref() {
// roots..heads -> :heads & ~(:roots)
RevsetExpression::Range { roots, heads } => {
Some(heads.ancestors().intersection(&roots.ancestors().negated()))
}
RevsetExpression::Difference(expression1, expression2) => {
Some(expression1.intersection(&expression2.negated()))
}
@ -2639,6 +2663,46 @@ mod tests {
)
"###);
// Range expression.
insta::assert_debug_snapshot!(optimize(parse(":foo & ~:bar").unwrap()), @r###"
Range {
roots: Symbol(
"bar",
),
heads: Symbol(
"foo",
),
}
"###);
insta::assert_debug_snapshot!(optimize(parse("~:foo & :bar").unwrap()), @r###"
Range {
roots: Symbol(
"foo",
),
heads: Symbol(
"bar",
),
}
"###);
insta::assert_debug_snapshot!(optimize(parse("foo..").unwrap()), @r###"
Range {
roots: Symbol(
"foo",
),
heads: VisibleHeads,
}
"###);
insta::assert_debug_snapshot!(optimize(parse("foo..bar").unwrap()), @r###"
Range {
roots: Symbol(
"foo",
),
heads: Symbol(
"bar",
),
}
"###);
// Double/triple negates.
insta::assert_debug_snapshot!(optimize(parse("foo & ~~bar").unwrap()), @r###"
Intersection(