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refs: leverage Conflict::flatten() and simplify() to premerge ref targets

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The order of conflicted ids slightly changed since Conflict::simplify()
tries to preserve diff pairs. It shouldn't matter so long as the result is
stable.
This commit is contained in:
Yuya Nishihara 2023-07-07 19:57:34 +09:00
parent ddaf226108
commit 424786def1
2 changed files with 66 additions and 26 deletions
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60
lib/src/refs.rs
View file

@ -15,6 +15,7 @@
#![allow(missing_docs)]
use crate::backend::CommitId;
use crate::conflicts::Conflict;
use crate::index::Index;
use crate::merge::trivial_merge;
use crate::op_store::{BranchTarget, RefTarget};
@ -29,22 +30,42 @@ pub fn merge_ref_targets(
return resolved.cloned();
}
let mut removes = vec![];
let mut adds = vec![];
if let Some(left) = left {
removes.extend_from_slice(left.removes());
adds.extend_from_slice(left.adds());
}
if let Some(base) = base {
// Note that these are backwards (because the base is subtracted).
removes.extend_from_slice(base.adds());
adds.extend_from_slice(base.removes());
}
if let Some(right) = right {
removes.extend_from_slice(right.removes());
adds.extend_from_slice(right.adds());
}
let conflict = Conflict::new(
vec![ref_target_to_conflict(base)],
vec![ref_target_to_conflict(left), ref_target_to_conflict(right)],
)
.flatten()
.simplify();
match conflict.as_resolved() {
Some(Some(id)) => Some(RefTarget::Normal(id.clone())),
Some(None) => None, // Deleted ref
None => {
let (removes, adds) = conflict.into_legacy_form();
merge_ref_targets_non_trivial(index, removes, adds)
}
}
}
// TODO: Make RefTarget store or be aliased to Conflict<Option<CommitId>>.
// Since new conflict type can represent a deleted/absent ref, we might have
// to replace Option<RefTarget> with it. Map API might be a bit trickier.
fn ref_target_to_conflict(maybe_target: Option<&RefTarget>) -> Conflict<Option<CommitId>> {
if let Some(target) = maybe_target {
Conflict::from_legacy_form(
target.removes().iter().cloned(),
target.adds().iter().cloned(),
)
} else {
Conflict::resolved(None) // Deleted or absent ref
}
}
fn merge_ref_targets_non_trivial(
index: &dyn Index,
mut removes: Vec<CommitId>,
mut adds: Vec<CommitId>,
) -> Option<RefTarget> {
while let Some((maybe_remove_index, add_index)) = find_pair_to_remove(index, &removes, &adds) {
if let Some(remove_index) = maybe_remove_index {
removes.remove(remove_index);
@ -66,15 +87,6 @@ fn find_pair_to_remove(
removes: &[CommitId],
adds: &[CommitId],
) -> Option<(Option<usize>, usize)> {
// Removes pairs of matching adds and removes.
for (remove_index, remove) in removes.iter().enumerate() {
for (add_index, add) in adds.iter().enumerate() {
if add == remove {
return Some((Some(remove_index), add_index));
}
}
}
// If a "remove" is an ancestor of two different "adds" and one of the
// "adds" is an ancestor of the other, then pick the descendant.
for (add_index1, add1) in adds.iter().enumerate() {

32
lib/tests/test_refs.rs
View file

@ -217,6 +217,13 @@ fn test_merge_ref_targets() {
);
// Existing conflict on left, right moves an "add" sideways
//
// Under the hood, the conflict is simplified as below:
// ```
// 3 4 5 3 4 5 5 4
// 2 / => 2 3 => 2
// 3
// ```
assert_eq!(
merge_ref_targets(
index,
@ -229,11 +236,18 @@ fn test_merge_ref_targets() {
),
Some(RefTarget::Conflict {
removes: vec![commit2.id().clone()],
adds: vec![commit4.id().clone(), commit5.id().clone()]
adds: vec![commit5.id().clone(), commit4.id().clone()]
})
);
// Existing conflict on right, left moves an "add" sideways
//
// Under the hood, the conflict is simplified as below:
// ```
// 5 3 4 5 3 4 5 4
// \ 2 => 3 2 => 2
// 3
// ```
assert_eq!(
merge_ref_targets(
index,
@ -252,6 +266,13 @@ fn test_merge_ref_targets() {
// Existing conflict on left, right moves an "add" backwards, past point of
// divergence
//
// Under the hood, the conflict is simplified as below:
// ```
// 3 4 1 3 4 1 1 4
// 2 / => 2 3 => 2
// 3
// ```
assert_eq!(
merge_ref_targets(
index,
@ -264,12 +285,19 @@ fn test_merge_ref_targets() {
),
Some(RefTarget::Conflict {
removes: vec![commit2.id().clone()],
adds: vec![commit4.id().clone(), commit1.id().clone()]
adds: vec![commit1.id().clone(), commit4.id().clone()]
})
);
// Existing conflict on right, left moves an "add" backwards, past point of
// divergence
//
// Under the hood, the conflict is simplified as below:
// ```
// 1 3 4 1 3 4 1 4
// \ 2 => 3 2 => 2
// 3
// ```
assert_eq!(
merge_ref_targets(
index,