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Make Buffer::edit and MultiBuffer::edit resilient to inverted ranges

Browse source 
Previously, we would accept edits containing out-of-order ranges. When
generating such ranges in our randomized tests, many invariants started
breaking causing e.g. undo/redo to misbehave and operation application
to panic.

In theory, we should never pass inverted ranges, but this commit changes
the above functions to swap the start and the end when that occurs to avoid
breaking the entire system and panicking.
This commit is contained in:
Antonio Scandurra 2022-06-06 15:15:50 +02:00
parent 939020a652
commit 8826ad5ddd
3 changed files with 55 additions and 25 deletions
Download patch file Download diff file Expand all files Collapse all files

2
crates/editor/src/display_map.rs
View file

@ -693,7 +693,7 @@ pub mod tests {
}
}
_ => {
buffer.update(cx, |buffer, cx| buffer.randomly_edit(&mut rng, 5, cx));
buffer.update(cx, |buffer, cx| buffer.randomly_mutate(&mut rng, 5, cx));
}
}

67
crates/editor/src/multi_buffer.rs
View file

@ -17,6 +17,7 @@ use std::{
cell::{Ref, RefCell},
cmp, fmt, io,
iter::{self, FromIterator},
mem,
ops::{Range, RangeBounds, Sub},
str,
sync::Arc,
@ -298,7 +299,7 @@ impl MultiBuffer {
pub fn edit_internal<I, S, T>(
&mut self,
edits_iter: I,
edits: I,
autoindent: bool,
cx: &mut ModelContext<Self>,
) where
@ -310,14 +311,16 @@ impl MultiBuffer {
return;
}
let snapshot = self.read(cx);
let edits = edits.into_iter().map(|(range, new_text)| {
let mut range = range.start.to_offset(&snapshot)..range.end.to_offset(&snapshot);
if range.start > range.end {
mem::swap(&mut range.start, &mut range.end);
}
(range, new_text)
});
if let Some(buffer) = self.as_singleton() {
let snapshot = self.read(cx);
let edits = edits_iter.into_iter().map(|(range, new_text)| {
(
range.start.to_offset(&snapshot)..range.end.to_offset(&snapshot),
new_text,
)
});
return buffer.update(cx, |buffer, cx| {
let language_name = buffer.language().map(|language| language.name());
let indent_size = cx.global::<Settings>().tab_size(language_name.as_deref());
@ -329,29 +332,26 @@ impl MultiBuffer {
});
}
let snapshot = self.read(cx);
let mut buffer_edits: HashMap<usize, Vec<(Range<usize>, Arc<str>, bool)>> =
Default::default();
let mut cursor = snapshot.excerpts.cursor::<usize>();
for (range, new_text) in edits_iter {
for (range, new_text) in edits {
let new_text: Arc<str> = new_text.into();
let start = range.start.to_offset(&snapshot);
let end = range.end.to_offset(&snapshot);
cursor.seek(&start, Bias::Right, &());
if cursor.item().is_none() && start == *cursor.start() {
cursor.seek(&range.start, Bias::Right, &());
if cursor.item().is_none() && range.start == *cursor.start() {
cursor.prev(&());
}
let start_excerpt = cursor.item().expect("start offset out of bounds");
let start_overshoot = start - cursor.start();
let start_overshoot = range.start - cursor.start();
let buffer_start =
start_excerpt.range.start.to_offset(&start_excerpt.buffer) + start_overshoot;
cursor.seek(&end, Bias::Right, &());
if cursor.item().is_none() && end == *cursor.start() {
cursor.seek(&range.end, Bias::Right, &());
if cursor.item().is_none() && range.end == *cursor.start() {
cursor.prev(&());
}
let end_excerpt = cursor.item().expect("end offset out of bounds");
let end_overshoot = end - cursor.start();
let end_overshoot = range.end - cursor.start();
let buffer_end = end_excerpt.range.start.to_offset(&end_excerpt.buffer) + end_overshoot;
if start_excerpt.id == end_excerpt.id {
@ -373,7 +373,7 @@ impl MultiBuffer {
.or_insert(Vec::new())
.push((end_excerpt_range, new_text.clone(), false));
cursor.seek(&start, Bias::Right, &());
cursor.seek(&range.start, Bias::Right, &());
cursor.next(&());
while let Some(excerpt) = cursor.item() {
if excerpt.id == end_excerpt.id {
@ -1310,7 +1310,11 @@ impl MultiBuffer {
let end = snapshot.clip_offset(rng.gen_range(new_start..=snapshot.len()), Bias::Right);
let start = snapshot.clip_offset(rng.gen_range(new_start..=end), Bias::Right);
last_end = Some(end);
let range = start..end;
let mut range = start..end;
if rng.gen_bool(0.2) {
mem::swap(&mut range.start, &mut range.end);
}
let new_text_len = rng.gen_range(0..10);
let new_text: String = RandomCharIter::new(&mut *rng).take(new_text_len).collect();
@ -1414,8 +1418,27 @@ impl MultiBuffer {
mutation_count: usize,
cx: &mut ModelContext<Self>,
) {
use rand::prelude::*;
if rng.gen_bool(0.7) || self.singleton {
self.randomly_edit(rng, mutation_count, cx);
let buffer = self
.buffers
.borrow()
.values()
.choose(rng)
.map(|state| state.buffer.clone());
if rng.gen() && buffer.is_some() {
buffer.unwrap().update(cx, |buffer, cx| {
if rng.gen() {
buffer.randomly_edit(rng, mutation_count, cx);
} else {
buffer.randomly_undo_redo(rng, cx);
}
});
} else {
self.randomly_edit(rng, mutation_count, cx);
}
} else {
self.randomly_edit_excerpts(rng, mutation_count, cx);
}
@ -3330,7 +3353,7 @@ mod tests {
});
buffer_2.update(cx, |buffer, cx| {
buffer.edit([(0..0, "Y")], cx);
buffer.edit([(6..0, "Z")], cx);
buffer.edit([(6..6, "Z")], cx);
});
let new_snapshot = multibuffer.read(cx).snapshot(cx);

11
crates/language/src/buffer.rs
View file

@ -23,6 +23,7 @@ use std::{
ffi::OsString,
future::Future,
iter::{Iterator, Peekable},
mem,
ops::{Deref, DerefMut, Range},
path::{Path, PathBuf},
str,
@ -1108,7 +1109,10 @@ impl Buffer {
// Skip invalid edits and coalesce contiguous ones.
let mut edits: Vec<(Range<usize>, Arc<str>)> = Vec::new();
for (range, new_text) in edits_iter {
let range = range.start.to_offset(self)..range.end.to_offset(self);
let mut range = range.start.to_offset(self)..range.end.to_offset(self);
if range.start > range.end {
mem::swap(&mut range.start, &mut range.end);
}
let new_text = new_text.into();
if !new_text.is_empty() || !range.is_empty() {
if let Some((prev_range, prev_text)) = edits.last_mut() {
@ -1452,7 +1456,10 @@ impl Buffer {
}
let new_start = last_end.map_or(0, |last_end| last_end + 1);
let range = self.random_byte_range(new_start, rng);
let mut range = self.random_byte_range(new_start, rng);
if rng.gen_bool(0.2) {
mem::swap(&mut range.start, &mut range.end);
}
last_end = Some(range.end);
let new_text_len = rng.gen_range(0..10);