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Don't replace parent node when inserting as first child in algo::diff #6512

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merged 1 commit into from
Nov 9, 2020
Merged

Don't replace parent node when inserting as first child in algo::diff #6512

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125 changes: 89 additions & 36 deletions crates/syntax/src/algo.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -111,18 +111,28 @@ pub enum InsertPosition<T> {

type FxIndexMap<K, V> = IndexMap<K, V, BuildHasherDefault<rustc_hash::FxHasher>>;

#[derive(Debug, Hash, PartialEq, Eq)]
enum TreeDiffInsertPos {
After(SyntaxElement),
AsFirstChild(SyntaxElement),
}

#[derive(Debug)]
pub struct TreeDiff {
replacements: FxHashMap<SyntaxElement, SyntaxElement>,
deletions: Vec<SyntaxElement>,
// the vec as well as the indexmap are both here to preserve order
insertions: FxIndexMap<SyntaxElement, Vec<SyntaxElement>>,
insertions: FxIndexMap<TreeDiffInsertPos, Vec<SyntaxElement>>,
}

impl TreeDiff {
pub fn into_text_edit(&self, builder: &mut TextEditBuilder) {
for (anchor, to) in self.insertions.iter() {
to.iter().for_each(|to| builder.insert(anchor.text_range().end(), to.to_string()));
let offset = match anchor {
TreeDiffInsertPos::After(it) => it.text_range().end(),
TreeDiffInsertPos::AsFirstChild(it) => it.text_range().start(),
};
to.iter().for_each(|to| builder.insert(offset, to.to_string()));
}
for (from, to) in self.replacements.iter() {
builder.replace(from.text_range(), to.to_string())
Expand Down Expand Up @@ -188,19 +198,20 @@ pub fn diff(from: &SyntaxNode, to: &SyntaxNode) -> TreeDiff {
let lhs_child = lhs_children.next();
match (lhs_child.clone(), rhs_children.next()) {
(None, None) => break,
(None, Some(element)) => match last_lhs.clone() {
Some(prev) => {
mark::hit!(diff_insert);
diff.insertions.entry(prev).or_insert_with(Vec::new).push(element);
}
// first iteration, this means we got no anchor element to insert after
// therefor replace the parent node instead
None => {
mark::hit!(diff_replace_parent);
diff.replacements.insert(lhs.clone().into(), rhs.clone().into());
break;
}
},
(None, Some(element)) => {
let insert_pos = match last_lhs.clone() {
Some(prev) => {
mark::hit!(diff_insert);
TreeDiffInsertPos::After(prev)
}
// first iteration, insert into out parent as the first child
None => {
mark::hit!(diff_insert_as_first_child);
TreeDiffInsertPos::AsFirstChild(lhs.clone().into())
}
};
diff.insertions.entry(insert_pos).or_insert_with(Vec::new).push(element);
}
(Some(element), None) => {
mark::hit!(diff_delete);
diff.deletions.push(element);
Expand All @@ -224,8 +235,15 @@ pub fn diff(from: &SyntaxNode, to: &SyntaxNode) -> TreeDiff {
}
}
let drain = look_ahead_scratch.drain(..);
if let Some(prev) = last_lhs.clone().filter(|_| insert) {
diff.insertions.entry(prev).or_insert_with(Vec::new).extend(drain);
if insert {
let insert_pos = if let Some(prev) = last_lhs.clone().filter(|_| insert) {
TreeDiffInsertPos::After(prev)
} else {
mark::hit!(insert_first_child);
TreeDiffInsertPos::AsFirstChild(lhs.clone().into())
};

diff.insertions.entry(insert_pos).or_insert_with(Vec::new).extend(drain);
rhs_children = rhs_children_clone;
} else {
go(diff, lhs_ele, rhs_ele)
Expand Down Expand Up @@ -629,18 +647,19 @@ mod tests {

#[test]
fn replace_parent() {
mark::check!(diff_replace_parent);
mark::check!(diff_insert_as_first_child);
check_diff(
r#""#,
r#"use foo::bar;"#,
expect![[r#"
insertions:


Line 0: AsFirstChild(Node(SOURCE_FILE@0..0))
-> use foo::bar;

replacements:

Line 0: Node(SOURCE_FILE@0..0) -> use foo::bar;


deletions:

Expand All @@ -663,7 +682,7 @@ use baz;"#,
expect![[r#"
insertions:

Line 2: Node(USE@10..18)
Line 2: After(Node(USE@10..18))
-> "\n"
-> use baz;

Expand Down Expand Up @@ -691,7 +710,7 @@ use baz;"#,
expect![[r#"
insertions:

Line 2: Token(WHITESPACE@9..10 "\n")
Line 2: After(Token(WHITESPACE@9..10 "\n"))
-> use bar;
-> "\n"

Expand Down Expand Up @@ -719,7 +738,7 @@ use baz;"#,
expect![[r#"
insertions:

Line 0: Token(WHITESPACE@0..1 "\n")
Line 0: After(Token(WHITESPACE@0..1 "\n"))
-> use foo;
-> "\n"

Expand All @@ -734,6 +753,36 @@ use baz;"#,
)
}

#[test]
fn first_child_insertion() {
mark::check!(insert_first_child);
check_diff(
r#"fn main() {
stdi
}"#,
r#"use foo::bar;

fn main() {
stdi
}"#,
expect![[r#"
insertions:

Line 0: AsFirstChild(Node(SOURCE_FILE@0..30))
-> use foo::bar;
-> "\n\n "

replacements:



deletions:


"#]],
);
}

#[test]
fn delete_last() {
mark::check!(diff_delete);
Expand Down Expand Up @@ -776,7 +825,7 @@ use crate::AstNode;
expect![[r#"
insertions:

Line 1: Node(USE@1..35)
Line 1: After(Node(USE@1..35))
-> "\n\n"
-> use crate::AstNode;

Expand Down Expand Up @@ -842,10 +891,10 @@ use std::ops::{self, RangeInclusive};
expect![[r#"
insertions:

Line 2: Node(PATH_SEGMENT@5..8)
Line 2: After(Node(PATH_SEGMENT@5..8))
-> ::
-> fmt
Line 6: Token(WHITESPACE@86..87 "\n")
Line 6: After(Token(WHITESPACE@86..87 "\n"))
-> use std::hash::BuildHasherDefault;
-> "\n"
-> use std::ops::{self, RangeInclusive};
Expand Down Expand Up @@ -889,14 +938,14 @@ fn main() {
expect![[r#"
insertions:

Line 3: Node(BLOCK_EXPR@40..63)
Line 3: After(Node(BLOCK_EXPR@40..63))
-> " "
-> match Err(92) {
Ok(it) => it,
_ => return,
}
-> ;
Line 3: Node(IF_EXPR@17..63)
Line 3: After(Node(IF_EXPR@17..63))
-> "\n "
-> foo(x);

Expand Down Expand Up @@ -931,14 +980,18 @@ fn main() {
_ => format!("{}", syn),
};

let insertions = diff.insertions.iter().format_with("\n", |(k, v), f| {
f(&format!(
"Line {}: {:?}\n-> {}",
line_number(k),
k,
v.iter().format_with("\n-> ", |v, f| f(&fmt_syntax(v)))
))
});
let insertions =
diff.insertions.iter().format_with("\n", |(k, v), f| -> Result<(), std::fmt::Error> {
f(&format!(
"Line {}: {:?}\n-> {}",
line_number(match k {
super::TreeDiffInsertPos::After(syn) => syn,
super::TreeDiffInsertPos::AsFirstChild(syn) => syn,
}),
k,
v.iter().format_with("\n-> ", |v, f| f(&fmt_syntax(v)))
))
});

let replacements = diff
.replacements
Expand Down