zed/crates/editor/src/inlay_hint_cache.rs

use std::{
    cmp,
    ops::{ControlFlow, Range},
    sync::Arc,
    time::Duration,
};

use crate::{
    display_map::Inlay, Anchor, Editor, ExcerptId, InlayId, MultiBuffer, MultiBufferSnapshot,
};
use anyhow::Context;
use clock::Global;
use futures::future;
use gpui::{ModelContext, ModelHandle, Task, ViewContext};
use language::{language_settings::InlayHintKind, Buffer, BufferSnapshot};
use parking_lot::RwLock;
use project::{InlayHint, ResolveState};

use collections::{hash_map, HashMap, HashSet};
use language::language_settings::InlayHintSettings;
use smol::lock::Semaphore;
use sum_tree::Bias;
use text::{ToOffset, ToPoint};
use util::post_inc;

pub struct InlayHintCache {
    hints: HashMap<ExcerptId, Arc<RwLock<CachedExcerptHints>>>,
    allowed_hint_kinds: HashSet<Option<InlayHintKind>>,
    version: usize,
    pub(super) enabled: bool,
    update_tasks: HashMap<ExcerptId, TasksForRanges>,
    lsp_request_limiter: Arc<Semaphore>,
}

#[derive(Debug)]
struct TasksForRanges {
    tasks: Vec<Task<()>>,
    sorted_ranges: Vec<Range<language::Anchor>>,
}

#[derive(Debug)]
pub struct CachedExcerptHints {
    version: usize,
    buffer_version: Global,
    buffer_id: u64,
    ordered_hints: Vec<InlayId>,
    hints_by_id: HashMap<InlayId, InlayHint>,
}

#[derive(Debug, Clone, Copy)]
pub enum InvalidationStrategy {
    RefreshRequested,
    BufferEdited,
    None,
}

#[derive(Debug, Default)]
pub struct InlaySplice {
    pub to_remove: Vec<InlayId>,
    pub to_insert: Vec<Inlay>,
}

#[derive(Debug)]
struct ExcerptHintsUpdate {
    excerpt_id: ExcerptId,
    remove_from_visible: Vec<InlayId>,
    remove_from_cache: HashSet<InlayId>,
    add_to_cache: Vec<InlayHint>,
}

#[derive(Debug, Clone, Copy)]
struct ExcerptQuery {
    buffer_id: u64,
    excerpt_id: ExcerptId,
    cache_version: usize,
    invalidate: InvalidationStrategy,
    reason: &'static str,
}

impl InvalidationStrategy {
    fn should_invalidate(&self) -> bool {
        matches!(
            self,
            InvalidationStrategy::RefreshRequested | InvalidationStrategy::BufferEdited
        )
    }
}

impl TasksForRanges {
    fn new(query_ranges: QueryRanges, task: Task<()>) -> Self {
        let mut sorted_ranges = Vec::new();
        sorted_ranges.extend(query_ranges.before_visible);
        sorted_ranges.extend(query_ranges.visible);
        sorted_ranges.extend(query_ranges.after_visible);
        Self {
            tasks: vec![task],
            sorted_ranges,
        }
    }

    fn update_cached_tasks(
        &mut self,
        buffer_snapshot: &BufferSnapshot,
        query_ranges: QueryRanges,
        invalidate: InvalidationStrategy,
        spawn_task: impl FnOnce(QueryRanges) -> Task<()>,
    ) {
        let query_ranges = if invalidate.should_invalidate() {
            self.tasks.clear();
            self.sorted_ranges.clear();
            query_ranges
        } else {
            let mut non_cached_query_ranges = query_ranges;
            non_cached_query_ranges.before_visible = non_cached_query_ranges
                .before_visible
                .into_iter()
                .flat_map(|query_range| {
                    self.remove_cached_ranges_from_query(buffer_snapshot, query_range)
                })
                .collect();
            non_cached_query_ranges.visible = non_cached_query_ranges
                .visible
                .into_iter()
                .flat_map(|query_range| {
                    self.remove_cached_ranges_from_query(buffer_snapshot, query_range)
                })
                .collect();
            non_cached_query_ranges.after_visible = non_cached_query_ranges
                .after_visible
                .into_iter()
                .flat_map(|query_range| {
                    self.remove_cached_ranges_from_query(buffer_snapshot, query_range)
                })
                .collect();
            non_cached_query_ranges
        };

        if !query_ranges.is_empty() {
            self.tasks.push(spawn_task(query_ranges));
        }
    }

    fn remove_cached_ranges_from_query(
        &mut self,
        buffer_snapshot: &BufferSnapshot,
        query_range: Range<language::Anchor>,
    ) -> Vec<Range<language::Anchor>> {
        let mut ranges_to_query = Vec::new();
        let mut latest_cached_range = None::<&mut Range<language::Anchor>>;
        for cached_range in self
            .sorted_ranges
            .iter_mut()
            .skip_while(|cached_range| {
                cached_range
                    .end
                    .cmp(&query_range.start, buffer_snapshot)
                    .is_lt()
            })
            .take_while(|cached_range| {
                cached_range
                    .start
                    .cmp(&query_range.end, buffer_snapshot)
                    .is_le()
            })
        {
            match latest_cached_range {
                Some(latest_cached_range) => {
                    if latest_cached_range.end.offset.saturating_add(1) < cached_range.start.offset
                    {
                        ranges_to_query.push(latest_cached_range.end..cached_range.start);
                        cached_range.start = latest_cached_range.end;
                    }
                }
                None => {
                    if query_range
                        .start
                        .cmp(&cached_range.start, buffer_snapshot)
                        .is_lt()
                    {
                        ranges_to_query.push(query_range.start..cached_range.start);
                        cached_range.start = query_range.start;
                    }
                }
            }
            latest_cached_range = Some(cached_range);
        }

        match latest_cached_range {
            Some(latest_cached_range) => {
                if latest_cached_range.end.offset.saturating_add(1) < query_range.end.offset {
                    ranges_to_query.push(latest_cached_range.end..query_range.end);
                    latest_cached_range.end = query_range.end;
                }
            }
            None => {
                ranges_to_query.push(query_range.clone());
                self.sorted_ranges.push(query_range);
                self.sorted_ranges
                    .sort_by(|range_a, range_b| range_a.start.cmp(&range_b.start, buffer_snapshot));
            }
        }

        ranges_to_query
    }

    fn invalidate_range(&mut self, buffer: &BufferSnapshot, range: &Range<language::Anchor>) {
        self.sorted_ranges = self
            .sorted_ranges
            .drain(..)
            .filter_map(|mut cached_range| {
                if cached_range.start.cmp(&range.end, buffer).is_gt()
                    || cached_range.end.cmp(&range.start, buffer).is_lt()
                {
                    Some(vec![cached_range])
                } else if cached_range.start.cmp(&range.start, buffer).is_ge()
                    && cached_range.end.cmp(&range.end, buffer).is_le()
                {
                    None
                } else if range.start.cmp(&cached_range.start, buffer).is_ge()
                    && range.end.cmp(&cached_range.end, buffer).is_le()
                {
                    Some(vec![
                        cached_range.start..range.start,
                        range.end..cached_range.end,
                    ])
                } else if cached_range.start.cmp(&range.start, buffer).is_ge() {
                    cached_range.start = range.end;
                    Some(vec![cached_range])
                } else {
                    cached_range.end = range.start;
                    Some(vec![cached_range])
                }
            })
            .flatten()
            .collect();
    }
}

impl InlayHintCache {
    pub fn new(inlay_hint_settings: InlayHintSettings) -> Self {
        Self {
            allowed_hint_kinds: inlay_hint_settings.enabled_inlay_hint_kinds(),
            enabled: inlay_hint_settings.enabled,
            hints: HashMap::default(),
            update_tasks: HashMap::default(),
            version: 0,
            lsp_request_limiter: Arc::new(Semaphore::new(MAX_CONCURRENT_LSP_REQUESTS)),
        }
    }

    pub fn update_settings(
        &mut self,
        multi_buffer: &ModelHandle<MultiBuffer>,
        new_hint_settings: InlayHintSettings,
        visible_hints: Vec<Inlay>,
        cx: &mut ViewContext<Editor>,
    ) -> ControlFlow<Option<InlaySplice>> {
        let new_allowed_hint_kinds = new_hint_settings.enabled_inlay_hint_kinds();
        match (self.enabled, new_hint_settings.enabled) {
            (false, false) => {
                self.allowed_hint_kinds = new_allowed_hint_kinds;
                ControlFlow::Break(None)
            }
            (true, true) => {
                if new_allowed_hint_kinds == self.allowed_hint_kinds {
                    ControlFlow::Break(None)
                } else {
                    let new_splice = self.new_allowed_hint_kinds_splice(
                        multi_buffer,
                        &visible_hints,
                        &new_allowed_hint_kinds,
                        cx,
                    );
                    if new_splice.is_some() {
                        self.version += 1;
                        self.allowed_hint_kinds = new_allowed_hint_kinds;
                    }
                    ControlFlow::Break(new_splice)
                }
            }
            (true, false) => {
                self.enabled = new_hint_settings.enabled;
                self.allowed_hint_kinds = new_allowed_hint_kinds;
                if self.hints.is_empty() {
                    ControlFlow::Break(None)
                } else {
                    self.clear();
                    ControlFlow::Break(Some(InlaySplice {
                        to_remove: visible_hints.iter().map(|inlay| inlay.id).collect(),
                        to_insert: Vec::new(),
                    }))
                }
            }
            (false, true) => {
                self.enabled = new_hint_settings.enabled;
                self.allowed_hint_kinds = new_allowed_hint_kinds;
                ControlFlow::Continue(())
            }
        }
    }

    pub fn spawn_hint_refresh(
        &mut self,
        reason: &'static str,
        excerpts_to_query: HashMap<ExcerptId, (ModelHandle<Buffer>, Global, Range<usize>)>,
        invalidate: InvalidationStrategy,
        cx: &mut ViewContext<Editor>,
    ) -> Option<InlaySplice> {
        if !self.enabled {
            return None;
        }

        let mut invalidated_hints = Vec::new();
        if invalidate.should_invalidate() {
            self.update_tasks
                .retain(|task_excerpt_id, _| excerpts_to_query.contains_key(task_excerpt_id));
            self.hints.retain(|cached_excerpt, cached_hints| {
                let retain = excerpts_to_query.contains_key(cached_excerpt);
                if !retain {
                    invalidated_hints.extend(cached_hints.read().ordered_hints.iter().copied());
                }
                retain
            });
        }
        if excerpts_to_query.is_empty() && invalidated_hints.is_empty() {
            return None;
        }

        let cache_version = self.version + 1;
        cx.spawn(|editor, mut cx| async move {
            editor
                .update(&mut cx, |editor, cx| {
                    spawn_new_update_tasks(
                        editor,
                        reason,
                        excerpts_to_query,
                        invalidate,
                        cache_version,
                        cx,
                    )
                })
                .ok();
        })
        .detach();

        if invalidated_hints.is_empty() {
            None
        } else {
            Some(InlaySplice {
                to_remove: invalidated_hints,
                to_insert: Vec::new(),
            })
        }
    }

    fn new_allowed_hint_kinds_splice(
        &self,
        multi_buffer: &ModelHandle<MultiBuffer>,
        visible_hints: &[Inlay],
        new_kinds: &HashSet<Option<InlayHintKind>>,
        cx: &mut ViewContext<Editor>,
    ) -> Option<InlaySplice> {
        let old_kinds = &self.allowed_hint_kinds;
        if new_kinds == old_kinds {
            return None;
        }

        let mut to_remove = Vec::new();
        let mut to_insert = Vec::new();
        let mut shown_hints_to_remove = visible_hints.iter().fold(
            HashMap::<ExcerptId, Vec<(Anchor, InlayId)>>::default(),
            |mut current_hints, inlay| {
                current_hints
                    .entry(inlay.position.excerpt_id)
                    .or_default()
                    .push((inlay.position, inlay.id));
                current_hints
            },
        );

        let multi_buffer = multi_buffer.read(cx);
        let multi_buffer_snapshot = multi_buffer.snapshot(cx);

        for (excerpt_id, excerpt_cached_hints) in &self.hints {
            let shown_excerpt_hints_to_remove =
                shown_hints_to_remove.entry(*excerpt_id).or_default();
            let excerpt_cached_hints = excerpt_cached_hints.read();
            let mut excerpt_cache = excerpt_cached_hints.ordered_hints.iter().fuse().peekable();
            shown_excerpt_hints_to_remove.retain(|(shown_anchor, shown_hint_id)| {
                let Some(buffer) = shown_anchor
                    .buffer_id
                    .and_then(|buffer_id| multi_buffer.buffer(buffer_id))
                else {
                    return false;
                };
                let buffer_snapshot = buffer.read(cx).snapshot();
                loop {
                    match excerpt_cache.peek() {
                        Some(&cached_hint_id) => {
                            let cached_hint = &excerpt_cached_hints.hints_by_id[cached_hint_id];
                            if cached_hint_id == shown_hint_id {
                                excerpt_cache.next();
                                return !new_kinds.contains(&cached_hint.kind);
                            }

                            match cached_hint
                                .position
                                .cmp(&shown_anchor.text_anchor, &buffer_snapshot)
                            {
                                cmp::Ordering::Less | cmp::Ordering::Equal => {
                                    if !old_kinds.contains(&cached_hint.kind)
                                        && new_kinds.contains(&cached_hint.kind)
                                    {
                                        to_insert.push(Inlay::hint(
                                            cached_hint_id.id(),
                                            multi_buffer_snapshot.anchor_in_excerpt(
                                                *excerpt_id,
                                                cached_hint.position,
                                            ),
                                            &cached_hint,
                                        ));
                                    }
                                    excerpt_cache.next();
                                }
                                cmp::Ordering::Greater => return true,
                            }
                        }
                        None => return true,
                    }
                }
            });

            for cached_hint_id in excerpt_cache {
                let maybe_missed_cached_hint = &excerpt_cached_hints.hints_by_id[cached_hint_id];
                let cached_hint_kind = maybe_missed_cached_hint.kind;
                if !old_kinds.contains(&cached_hint_kind) && new_kinds.contains(&cached_hint_kind) {
                    to_insert.push(Inlay::hint(
                        cached_hint_id.id(),
                        multi_buffer_snapshot
                            .anchor_in_excerpt(*excerpt_id, maybe_missed_cached_hint.position),
                        &maybe_missed_cached_hint,
                    ));
                }
            }
        }

        to_remove.extend(
            shown_hints_to_remove
                .into_values()
                .flatten()
                .map(|(_, hint_id)| hint_id),
        );
        if to_remove.is_empty() && to_insert.is_empty() {
            None
        } else {
            Some(InlaySplice {
                to_remove,
                to_insert,
            })
        }
    }

    pub fn remove_excerpts(&mut self, excerpts_removed: Vec<ExcerptId>) -> Option<InlaySplice> {
        let mut to_remove = Vec::new();
        for excerpt_to_remove in excerpts_removed {
            self.update_tasks.remove(&excerpt_to_remove);
            if let Some(cached_hints) = self.hints.remove(&excerpt_to_remove) {
                let cached_hints = cached_hints.read();
                to_remove.extend(cached_hints.ordered_hints.iter().copied());
            }
        }
        if to_remove.is_empty() {
            None
        } else {
            self.version += 1;
            Some(InlaySplice {
                to_remove,
                to_insert: Vec::new(),
            })
        }
    }

    pub fn clear(&mut self) {
        if !self.update_tasks.is_empty() || !self.hints.is_empty() {
            self.version += 1;
        }
        self.update_tasks.clear();
        self.hints.clear();
    }

    pub fn hint_by_id(&self, excerpt_id: ExcerptId, hint_id: InlayId) -> Option<InlayHint> {
        self.hints
            .get(&excerpt_id)?
            .read()
            .hints_by_id
            .get(&hint_id)
            .cloned()
    }

    pub fn hints(&self) -> Vec<InlayHint> {
        let mut hints = Vec::new();
        for excerpt_hints in self.hints.values() {
            let excerpt_hints = excerpt_hints.read();
            hints.extend(
                excerpt_hints
                    .ordered_hints
                    .iter()
                    .map(|id| &excerpt_hints.hints_by_id[id])
                    .cloned(),
            );
        }
        hints
    }

    pub fn version(&self) -> usize {
        self.version
    }

    pub fn spawn_hint_resolve(
        &self,
        buffer_id: u64,
        excerpt_id: ExcerptId,
        id: InlayId,
        cx: &mut ViewContext<'_, '_, Editor>,
    ) {
        if let Some(excerpt_hints) = self.hints.get(&excerpt_id) {
            let mut guard = excerpt_hints.write();
            if let Some(cached_hint) = guard.hints_by_id.get_mut(&id) {
                if let ResolveState::CanResolve(server_id, _) = &cached_hint.resolve_state {
                    let hint_to_resolve = cached_hint.clone();
                    let server_id = *server_id;
                    cached_hint.resolve_state = ResolveState::Resolving;
                    drop(guard);
                    cx.spawn(|editor, mut cx| async move {
                        let resolved_hint_task = editor.update(&mut cx, |editor, cx| {
                            editor
                                .buffer()
                                .read(cx)
                                .buffer(buffer_id)
                                .and_then(|buffer| {
                                    let project = editor.project.as_ref()?;
                                    Some(project.update(cx, |project, cx| {
                                        project.resolve_inlay_hint(
                                            hint_to_resolve,
                                            buffer,
                                            server_id,
                                            cx,
                                        )
                                    }))
                                })
                        })?;
                        if let Some(resolved_hint_task) = resolved_hint_task {
                            let mut resolved_hint =
                                resolved_hint_task.await.context("hint resolve task")?;
                            editor.update(&mut cx, |editor, _| {
                                if let Some(excerpt_hints) =
                                    editor.inlay_hint_cache.hints.get(&excerpt_id)
                                {
                                    let mut guard = excerpt_hints.write();
                                    if let Some(cached_hint) = guard.hints_by_id.get_mut(&id) {
                                        if cached_hint.resolve_state == ResolveState::Resolving {
                                            resolved_hint.resolve_state = ResolveState::Resolved;
                                            *cached_hint = resolved_hint;
                                        }
                                    }
                                }
                            })?;
                        }

                        anyhow::Ok(())
                    })
                    .detach_and_log_err(cx);
                }
            }
        }
    }
}

fn spawn_new_update_tasks(
    editor: &mut Editor,
    reason: &'static str,
    excerpts_to_query: HashMap<ExcerptId, (ModelHandle<Buffer>, Global, Range<usize>)>,
    invalidate: InvalidationStrategy,
    update_cache_version: usize,
    cx: &mut ViewContext<'_, '_, Editor>,
) {
    let visible_hints = Arc::new(editor.visible_inlay_hints(cx));
    for (excerpt_id, (excerpt_buffer, new_task_buffer_version, excerpt_visible_range)) in
        excerpts_to_query
    {
        if excerpt_visible_range.is_empty() {
            continue;
        }
        let buffer = excerpt_buffer.read(cx);
        let buffer_id = buffer.remote_id();
        let buffer_snapshot = buffer.snapshot();
        if buffer_snapshot
            .version()
            .changed_since(&new_task_buffer_version)
        {
            continue;
        }

        let cached_excerpt_hints = editor.inlay_hint_cache.hints.get(&excerpt_id).cloned();
        if let Some(cached_excerpt_hints) = &cached_excerpt_hints {
            let cached_excerpt_hints = cached_excerpt_hints.read();
            let cached_buffer_version = &cached_excerpt_hints.buffer_version;
            if cached_excerpt_hints.version > update_cache_version
                || cached_buffer_version.changed_since(&new_task_buffer_version)
            {
                continue;
            }
        };

        let (multi_buffer_snapshot, Some(query_ranges)) =
            editor.buffer.update(cx, |multi_buffer, cx| {
                (
                    multi_buffer.snapshot(cx),
                    determine_query_ranges(
                        multi_buffer,
                        excerpt_id,
                        &excerpt_buffer,
                        excerpt_visible_range,
                        cx,
                    ),
                )
            })
        else {
            return;
        };
        let query = ExcerptQuery {
            buffer_id,
            excerpt_id,
            cache_version: update_cache_version,
            invalidate,
            reason,
        };

        let new_update_task = |query_ranges| {
            new_update_task(
                query,
                query_ranges,
                multi_buffer_snapshot,
                buffer_snapshot.clone(),
                Arc::clone(&visible_hints),
                cached_excerpt_hints,
                Arc::clone(&editor.inlay_hint_cache.lsp_request_limiter),
                cx,
            )
        };

        match editor.inlay_hint_cache.update_tasks.entry(excerpt_id) {
            hash_map::Entry::Occupied(mut o) => {
                o.get_mut().update_cached_tasks(
                    &buffer_snapshot,
                    query_ranges,
                    invalidate,
                    new_update_task,
                );
            }
            hash_map::Entry::Vacant(v) => {
                v.insert(TasksForRanges::new(
                    query_ranges.clone(),
                    new_update_task(query_ranges),
                ));
            }
        }
    }
}

#[derive(Debug, Clone)]
struct QueryRanges {
    before_visible: Vec<Range<language::Anchor>>,
    visible: Vec<Range<language::Anchor>>,
    after_visible: Vec<Range<language::Anchor>>,
}

impl QueryRanges {
    fn is_empty(&self) -> bool {
        self.before_visible.is_empty() && self.visible.is_empty() && self.after_visible.is_empty()
    }
}

fn determine_query_ranges(
    multi_buffer: &mut MultiBuffer,
    excerpt_id: ExcerptId,
    excerpt_buffer: &ModelHandle<Buffer>,
    excerpt_visible_range: Range<usize>,
    cx: &mut ModelContext<'_, MultiBuffer>,
) -> Option<QueryRanges> {
    let full_excerpt_range = multi_buffer
        .excerpts_for_buffer(excerpt_buffer, cx)
        .into_iter()
        .find(|(id, _)| id == &excerpt_id)
        .map(|(_, range)| range.context)?;
    let buffer = excerpt_buffer.read(cx);
    let snapshot = buffer.snapshot();
    let excerpt_visible_len = excerpt_visible_range.end - excerpt_visible_range.start;

    let visible_range = if excerpt_visible_range.start == excerpt_visible_range.end {
        return None;
    } else {
        vec![
            buffer.anchor_before(snapshot.clip_offset(excerpt_visible_range.start, Bias::Left))
                ..buffer.anchor_after(snapshot.clip_offset(excerpt_visible_range.end, Bias::Right)),
        ]
    };

    let full_excerpt_range_end_offset = full_excerpt_range.end.to_offset(&snapshot);
    let after_visible_range_start = excerpt_visible_range
        .end
        .saturating_add(1)
        .min(full_excerpt_range_end_offset)
        .min(buffer.len());
    let after_visible_range = if after_visible_range_start == full_excerpt_range_end_offset {
        Vec::new()
    } else {
        let after_range_end_offset = after_visible_range_start
            .saturating_add(excerpt_visible_len)
            .min(full_excerpt_range_end_offset)
            .min(buffer.len());
        vec![
            buffer.anchor_before(snapshot.clip_offset(after_visible_range_start, Bias::Left))
                ..buffer.anchor_after(snapshot.clip_offset(after_range_end_offset, Bias::Right)),
        ]
    };

    let full_excerpt_range_start_offset = full_excerpt_range.start.to_offset(&snapshot);
    let before_visible_range_end = excerpt_visible_range
        .start
        .saturating_sub(1)
        .max(full_excerpt_range_start_offset);
    let before_visible_range = if before_visible_range_end == full_excerpt_range_start_offset {
        Vec::new()
    } else {
        let before_range_start_offset = before_visible_range_end
            .saturating_sub(excerpt_visible_len)
            .max(full_excerpt_range_start_offset);
        vec![
            buffer.anchor_before(snapshot.clip_offset(before_range_start_offset, Bias::Left))
                ..buffer.anchor_after(snapshot.clip_offset(before_visible_range_end, Bias::Right)),
        ]
    };

    Some(QueryRanges {
        before_visible: before_visible_range,
        visible: visible_range,
        after_visible: after_visible_range,
    })
}

const MAX_CONCURRENT_LSP_REQUESTS: usize = 5;
const INVISIBLE_RANGES_HINTS_REQUEST_DELAY_MILLIS: u64 = 400;

fn new_update_task(
    query: ExcerptQuery,
    query_ranges: QueryRanges,
    multi_buffer_snapshot: MultiBufferSnapshot,
    buffer_snapshot: BufferSnapshot,
    visible_hints: Arc<Vec<Inlay>>,
    cached_excerpt_hints: Option<Arc<RwLock<CachedExcerptHints>>>,
    lsp_request_limiter: Arc<Semaphore>,
    cx: &mut ViewContext<'_, '_, Editor>,
) -> Task<()> {
    cx.spawn(|editor, mut cx| async move {
        let closure_cx = cx.clone();
        let fetch_and_update_hints = |invalidate, range| {
            fetch_and_update_hints(
                editor.clone(),
                multi_buffer_snapshot.clone(),
                buffer_snapshot.clone(),
                Arc::clone(&visible_hints),
                cached_excerpt_hints.as_ref().map(Arc::clone),
                query,
                invalidate,
                range,
                Arc::clone(&lsp_request_limiter),
                closure_cx.clone(),
            )
        };
        let visible_range_update_results = future::join_all(query_ranges.visible.into_iter().map(
            |visible_range| async move {
                (
                    visible_range.clone(),
                    fetch_and_update_hints(query.invalidate.should_invalidate(), visible_range)
                        .await,
                )
            },
        ))
        .await;

        let hint_delay = cx.background().timer(Duration::from_millis(
            INVISIBLE_RANGES_HINTS_REQUEST_DELAY_MILLIS,
        ));

        let mut query_range_failed = |range: &Range<language::Anchor>, e: anyhow::Error| {
            log::error!("inlay hint update task for range {range:?} failed: {e:#}");
            editor
                .update(&mut cx, |editor, _| {
                    if let Some(task_ranges) = editor
                        .inlay_hint_cache
                        .update_tasks
                        .get_mut(&query.excerpt_id)
                    {
                        task_ranges.invalidate_range(&buffer_snapshot, &range);
                    }
                })
                .ok()
        };

        for (range, result) in visible_range_update_results {
            if let Err(e) = result {
                query_range_failed(&range, e);
            }
        }

        hint_delay.await;
        let invisible_range_update_results = future::join_all(
            query_ranges
                .before_visible
                .into_iter()
                .chain(query_ranges.after_visible.into_iter())
                .map(|invisible_range| async move {
                    (
                        invisible_range.clone(),
                        fetch_and_update_hints(false, invisible_range).await,
                    )
                }),
        )
        .await;
        for (range, result) in invisible_range_update_results {
            if let Err(e) = result {
                query_range_failed(&range, e);
            }
        }
    })
}

async fn fetch_and_update_hints(
    editor: gpui::WeakViewHandle<Editor>,
    multi_buffer_snapshot: MultiBufferSnapshot,
    buffer_snapshot: BufferSnapshot,
    visible_hints: Arc<Vec<Inlay>>,
    cached_excerpt_hints: Option<Arc<RwLock<CachedExcerptHints>>>,
    query: ExcerptQuery,
    invalidate: bool,
    fetch_range: Range<language::Anchor>,
    lsp_request_limiter: Arc<Semaphore>,
    mut cx: gpui::AsyncAppContext,
) -> anyhow::Result<()> {
    let (lsp_request_guard, got_throttled) = if query.invalidate.should_invalidate() {
        (None, false)
    } else {
        match lsp_request_limiter.try_acquire() {
            Some(guard) => (Some(guard), false),
            None => (Some(lsp_request_limiter.acquire().await), true),
        }
    };
    let fetch_range_to_log =
        fetch_range.start.to_point(&buffer_snapshot)..fetch_range.end.to_point(&buffer_snapshot);
    let inlay_hints_fetch_task = editor
        .update(&mut cx, |editor, cx| {
            if got_throttled {
                let query_not_around_visible_range = match editor.excerpt_visible_offsets(None, cx).remove(&query.excerpt_id) {
                    Some((_, _, current_visible_range)) => {
                        let visible_offset_length = current_visible_range.len();
                        let double_visible_range = current_visible_range
                            .start
                            .saturating_sub(visible_offset_length)
                            ..current_visible_range
                                .end
                                .saturating_add(visible_offset_length)
                                .min(buffer_snapshot.len());
                        !double_visible_range
                            .contains(&fetch_range.start.to_offset(&buffer_snapshot))
                            && !double_visible_range
                                .contains(&fetch_range.end.to_offset(&buffer_snapshot))
                    },
                    None => true,
                };
                if query_not_around_visible_range {
                    log::trace!("Fetching inlay hints for range {fetch_range_to_log:?} got throttled and fell off the current visible range, skipping.");
                    if let Some(task_ranges) = editor
                        .inlay_hint_cache
                        .update_tasks
                        .get_mut(&query.excerpt_id)
                    {
                        task_ranges.invalidate_range(&buffer_snapshot, &fetch_range);
                    }
                    return None;
                }
            }
            editor
                .buffer()
                .read(cx)
                .buffer(query.buffer_id)
                .and_then(|buffer| {
                    let project = editor.project.as_ref()?;
                    Some(project.update(cx, |project, cx| {
                        project.inlay_hints(buffer, fetch_range.clone(), cx)
                    }))
                })
        })
        .ok()
        .flatten();
    let new_hints = match inlay_hints_fetch_task {
        Some(fetch_task) => {
            log::debug!(
                "Fetching inlay hints for range {fetch_range_to_log:?}, reason: {query_reason}, invalidate: {invalidate}",
                query_reason = query.reason,
            );
            log::trace!(
                "Currently visible hints: {visible_hints:?}, cached hints present: {}",
                cached_excerpt_hints.is_some(),
            );
            fetch_task.await.context("inlay hint fetch task")?
        }
        None => return Ok(()),
    };
    drop(lsp_request_guard);
    log::debug!(
        "Fetched {} hints for range {fetch_range_to_log:?}",
        new_hints.len()
    );
    log::trace!("Fetched hints: {new_hints:?}");

    let background_task_buffer_snapshot = buffer_snapshot.clone();
    let backround_fetch_range = fetch_range.clone();
    let new_update = cx
        .background()
        .spawn(async move {
            calculate_hint_updates(
                query.excerpt_id,
                invalidate,
                backround_fetch_range,
                new_hints,
                &background_task_buffer_snapshot,
                cached_excerpt_hints,
                &visible_hints,
            )
        })
        .await;
    if let Some(new_update) = new_update {
        log::info!(
            "Applying update for range {fetch_range_to_log:?}: remove from editor: {}, remove from cache: {}, add to cache: {}",
            new_update.remove_from_visible.len(),
            new_update.remove_from_cache.len(),
            new_update.add_to_cache.len()
        );
        log::trace!("New update: {new_update:?}");
        editor
            .update(&mut cx, |editor, cx| {
                apply_hint_update(
                    editor,
                    new_update,
                    query,
                    invalidate,
                    buffer_snapshot,
                    multi_buffer_snapshot,
                    cx,
                );
            })
            .ok();
    }
    Ok(())
}

fn calculate_hint_updates(
    excerpt_id: ExcerptId,
    invalidate: bool,
    fetch_range: Range<language::Anchor>,
    new_excerpt_hints: Vec<InlayHint>,
    buffer_snapshot: &BufferSnapshot,
    cached_excerpt_hints: Option<Arc<RwLock<CachedExcerptHints>>>,
    visible_hints: &[Inlay],
) -> Option<ExcerptHintsUpdate> {
    let mut add_to_cache = Vec::<InlayHint>::new();
    let mut excerpt_hints_to_persist = HashMap::default();
    for new_hint in new_excerpt_hints {
        if !contains_position(&fetch_range, new_hint.position, buffer_snapshot) {
            continue;
        }
        let missing_from_cache = match &cached_excerpt_hints {
            Some(cached_excerpt_hints) => {
                let cached_excerpt_hints = cached_excerpt_hints.read();
                match cached_excerpt_hints
                    .ordered_hints
                    .binary_search_by(|probe| {
                        cached_excerpt_hints.hints_by_id[probe]
                            .position
                            .cmp(&new_hint.position, buffer_snapshot)
                    }) {
                    Ok(ix) => {
                        let mut missing_from_cache = true;
                        for id in &cached_excerpt_hints.ordered_hints[ix..] {
                            let cached_hint = &cached_excerpt_hints.hints_by_id[id];
                            if new_hint
                                .position
                                .cmp(&cached_hint.position, buffer_snapshot)
                                .is_gt()
                            {
                                break;
                            }
                            if cached_hint == &new_hint {
                                excerpt_hints_to_persist.insert(*id, cached_hint.kind);
                                missing_from_cache = false;
                            }
                        }
                        missing_from_cache
                    }
                    Err(_) => true,
                }
            }
            None => true,
        };
        if missing_from_cache {
            add_to_cache.push(new_hint);
        }
    }

    let mut remove_from_visible = Vec::new();
    let mut remove_from_cache = HashSet::default();
    if invalidate {
        remove_from_visible.extend(
            visible_hints
                .iter()
                .filter(|hint| hint.position.excerpt_id == excerpt_id)
                .map(|inlay_hint| inlay_hint.id)
                .filter(|hint_id| !excerpt_hints_to_persist.contains_key(hint_id)),
        );

        if let Some(cached_excerpt_hints) = &cached_excerpt_hints {
            let cached_excerpt_hints = cached_excerpt_hints.read();
            remove_from_cache.extend(
                cached_excerpt_hints
                    .ordered_hints
                    .iter()
                    .filter(|cached_inlay_id| {
                        !excerpt_hints_to_persist.contains_key(cached_inlay_id)
                    })
                    .copied(),
            );
        }
    }

    if remove_from_visible.is_empty() && remove_from_cache.is_empty() && add_to_cache.is_empty() {
        None
    } else {
        Some(ExcerptHintsUpdate {
            excerpt_id,
            remove_from_visible,
            remove_from_cache,
            add_to_cache,
        })
    }
}

fn contains_position(
    range: &Range<language::Anchor>,
    position: language::Anchor,
    buffer_snapshot: &BufferSnapshot,
) -> bool {
    range.start.cmp(&position, buffer_snapshot).is_le()
        && range.end.cmp(&position, buffer_snapshot).is_ge()
}

fn apply_hint_update(
    editor: &mut Editor,
    new_update: ExcerptHintsUpdate,
    query: ExcerptQuery,
    invalidate: bool,
    buffer_snapshot: BufferSnapshot,
    multi_buffer_snapshot: MultiBufferSnapshot,
    cx: &mut ViewContext<'_, '_, Editor>,
) {
    let cached_excerpt_hints = editor
        .inlay_hint_cache
        .hints
        .entry(new_update.excerpt_id)
        .or_insert_with(|| {
            Arc::new(RwLock::new(CachedExcerptHints {
                version: query.cache_version,
                buffer_version: buffer_snapshot.version().clone(),
                buffer_id: query.buffer_id,
                ordered_hints: Vec::new(),
                hints_by_id: HashMap::default(),
            }))
        });
    let mut cached_excerpt_hints = cached_excerpt_hints.write();
    match query.cache_version.cmp(&cached_excerpt_hints.version) {
        cmp::Ordering::Less => return,
        cmp::Ordering::Greater | cmp::Ordering::Equal => {
            cached_excerpt_hints.version = query.cache_version;
        }
    }

    let mut cached_inlays_changed = !new_update.remove_from_cache.is_empty();
    cached_excerpt_hints
        .ordered_hints
        .retain(|hint_id| !new_update.remove_from_cache.contains(hint_id));
    cached_excerpt_hints
        .hints_by_id
        .retain(|hint_id, _| !new_update.remove_from_cache.contains(hint_id));
    let mut splice = InlaySplice {
        to_remove: new_update.remove_from_visible,
        to_insert: Vec::new(),
    };
    for new_hint in new_update.add_to_cache {
        let insert_position = match cached_excerpt_hints
            .ordered_hints
            .binary_search_by(|probe| {
                cached_excerpt_hints.hints_by_id[probe]
                    .position
                    .cmp(&new_hint.position, &buffer_snapshot)
            }) {
            Ok(i) => {
                let mut insert_position = Some(i);
                for id in &cached_excerpt_hints.ordered_hints[i..] {
                    let cached_hint = &cached_excerpt_hints.hints_by_id[id];
                    if new_hint
                        .position
                        .cmp(&cached_hint.position, &buffer_snapshot)
                        .is_gt()
                    {
                        break;
                    }
                    if cached_hint.text() == new_hint.text() {
                        insert_position = None;
                        break;
                    }
                }
                insert_position
            }
            Err(i) => Some(i),
        };

        if let Some(insert_position) = insert_position {
            let new_inlay_id = post_inc(&mut editor.next_inlay_id);
            if editor
                .inlay_hint_cache
                .allowed_hint_kinds
                .contains(&new_hint.kind)
            {
                let new_hint_position =
                    multi_buffer_snapshot.anchor_in_excerpt(query.excerpt_id, new_hint.position);
                splice
                    .to_insert
                    .push(Inlay::hint(new_inlay_id, new_hint_position, &new_hint));
            }
            let new_id = InlayId::Hint(new_inlay_id);
            cached_excerpt_hints.hints_by_id.insert(new_id, new_hint);
            cached_excerpt_hints
                .ordered_hints
                .insert(insert_position, new_id);
            cached_inlays_changed = true;
        }
    }
    cached_excerpt_hints.buffer_version = buffer_snapshot.version().clone();
    drop(cached_excerpt_hints);

    if invalidate {
        let mut outdated_excerpt_caches = HashSet::default();
        for (excerpt_id, excerpt_hints) in &editor.inlay_hint_cache().hints {
            let excerpt_hints = excerpt_hints.read();
            if excerpt_hints.buffer_id == query.buffer_id
                && excerpt_id != &query.excerpt_id
                && buffer_snapshot
                    .version()
                    .changed_since(&excerpt_hints.buffer_version)
            {
                outdated_excerpt_caches.insert(*excerpt_id);
                splice
                    .to_remove
                    .extend(excerpt_hints.ordered_hints.iter().copied());
            }
        }
        cached_inlays_changed |= !outdated_excerpt_caches.is_empty();
        editor
            .inlay_hint_cache
            .hints
            .retain(|excerpt_id, _| !outdated_excerpt_caches.contains(excerpt_id));
    }

    let InlaySplice {
        to_remove,
        to_insert,
    } = splice;
    let displayed_inlays_changed = !to_remove.is_empty() || !to_insert.is_empty();
    if cached_inlays_changed || displayed_inlays_changed {
        editor.inlay_hint_cache.version += 1;
    }
    if displayed_inlays_changed {
        editor.splice_inlay_hints(to_remove, to_insert, cx)
    }
}

#[cfg(test)]
pub mod tests {
    use std::sync::atomic::{AtomicBool, AtomicU32, AtomicUsize, Ordering};

    use crate::{
        scroll::{autoscroll::Autoscroll, scroll_amount::ScrollAmount},
        serde_json::json,
        ExcerptRange,
    };
    use futures::StreamExt;
    use gpui::{executor::Deterministic, TestAppContext, ViewHandle};
    use itertools::Itertools;
    use language::{
        language_settings::AllLanguageSettingsContent, FakeLspAdapter, Language, LanguageConfig,
    };
    use lsp::FakeLanguageServer;
    use parking_lot::Mutex;
    use project::{FakeFs, Project};
    use settings::SettingsStore;
    use text::{Point, ToPoint};
    use workspace::Workspace;

    use crate::editor_tests::update_test_language_settings;

    use super::*;

    #[gpui::test]
    async fn test_basic_cache_update_with_duplicate_hints(cx: &mut gpui::TestAppContext) {
        let allowed_hint_kinds = HashSet::from_iter([None, Some(InlayHintKind::Type)]);
        init_test(cx, |settings| {
            settings.defaults.inlay_hints = Some(InlayHintSettings {
                enabled: true,
                show_type_hints: allowed_hint_kinds.contains(&Some(InlayHintKind::Type)),
                show_parameter_hints: allowed_hint_kinds.contains(&Some(InlayHintKind::Parameter)),
                show_other_hints: allowed_hint_kinds.contains(&None),
            })
        });

        let (file_with_hints, editor, fake_server) = prepare_test_objects(cx).await;
        let lsp_request_count = Arc::new(AtomicU32::new(0));
        fake_server
            .handle_request::<lsp::request::InlayHintRequest, _, _>(move |params, _| {
                let task_lsp_request_count = Arc::clone(&lsp_request_count);
                async move {
                    assert_eq!(
                        params.text_document.uri,
                        lsp::Url::from_file_path(file_with_hints).unwrap(),
                    );
                    let current_call_id =
                        Arc::clone(&task_lsp_request_count).fetch_add(1, Ordering::SeqCst);
                    let mut new_hints = Vec::with_capacity(2 * current_call_id as usize);
                    for _ in 0..2 {
                        let mut i = current_call_id;
                        loop {
                            new_hints.push(lsp::InlayHint {
                                position: lsp::Position::new(0, i),
                                label: lsp::InlayHintLabel::String(i.to_string()),
                                kind: None,
                                text_edits: None,
                                tooltip: None,
                                padding_left: None,
                                padding_right: None,
                                data: None,
                            });
                            if i == 0 {
                                break;
                            }
                            i -= 1;
                        }
                    }

                    Ok(Some(new_hints))
                }
            })
            .next()
            .await;
        cx.foreground().run_until_parked();

        let mut edits_made = 1;
        editor.update(cx, |editor, cx| {
            let expected_hints = vec!["0".to_string()];
            assert_eq!(
                expected_hints,
                cached_hint_labels(editor),
                "Should get its first hints when opening the editor"
            );
            assert_eq!(expected_hints, visible_hint_labels(editor, cx));
            let inlay_cache = editor.inlay_hint_cache();
            assert_eq!(
                inlay_cache.allowed_hint_kinds, allowed_hint_kinds,
                "Cache should use editor settings to get the allowed hint kinds"
            );
            assert_eq!(
                inlay_cache.version, edits_made,
                "The editor update the cache version after every cache/view change"
            );
        });

        editor.update(cx, |editor, cx| {
            editor.change_selections(None, cx, |s| s.select_ranges([13..13]));
            editor.handle_input("some change", cx);
            edits_made += 1;
        });
        cx.foreground().run_until_parked();
        editor.update(cx, |editor, cx| {
            let expected_hints = vec!["0".to_string(), "1".to_string()];
            assert_eq!(
                expected_hints,
                cached_hint_labels(editor),
                "Should get new hints after an edit"
            );
            assert_eq!(expected_hints, visible_hint_labels(editor, cx));
            let inlay_cache = editor.inlay_hint_cache();
            assert_eq!(
                inlay_cache.allowed_hint_kinds, allowed_hint_kinds,
                "Cache should use editor settings to get the allowed hint kinds"
            );
            assert_eq!(
                inlay_cache.version, edits_made,
                "The editor update the cache version after every cache/view change"
            );
        });

        fake_server
            .request::<lsp::request::InlayHintRefreshRequest>(())
            .await
            .expect("inlay refresh request failed");
        edits_made += 1;
        cx.foreground().run_until_parked();
        editor.update(cx, |editor, cx| {
            let expected_hints = vec!["0".to_string(), "1".to_string(), "2".to_string()];
            assert_eq!(
                expected_hints,
                cached_hint_labels(editor),
                "Should get new hints after hint refresh/ request"
            );
            assert_eq!(expected_hints, visible_hint_labels(editor, cx));
            let inlay_cache = editor.inlay_hint_cache();
            assert_eq!(
                inlay_cache.allowed_hint_kinds, allowed_hint_kinds,
                "Cache should use editor settings to get the allowed hint kinds"
            );
            assert_eq!(
                inlay_cache.version, edits_made,
                "The editor update the cache version after every cache/view change"
            );
        });
    }

    #[gpui::test]
    async fn test_cache_update_on_lsp_completion_tasks(cx: &mut gpui::TestAppContext) {
        init_test(cx, |settings| {
            settings.defaults.inlay_hints = Some(InlayHintSettings {
                enabled: true,
                show_type_hints: true,
                show_parameter_hints: true,
                show_other_hints: true,
            })
        });

        let (file_with_hints, editor, fake_server) = prepare_test_objects(cx).await;
        let lsp_request_count = Arc::new(AtomicU32::new(0));
        fake_server
            .handle_request::<lsp::request::InlayHintRequest, _, _>(move |params, _| {
                let task_lsp_request_count = Arc::clone(&lsp_request_count);
                async move {
                    assert_eq!(
                        params.text_document.uri,
                        lsp::Url::from_file_path(file_with_hints).unwrap(),
                    );
                    let current_call_id =
                        Arc::clone(&task_lsp_request_count).fetch_add(1, Ordering::SeqCst);
                    Ok(Some(vec![lsp::InlayHint {
                        position: lsp::Position::new(0, current_call_id),
                        label: lsp::InlayHintLabel::String(current_call_id.to_string()),
                        kind: None,
                        text_edits: None,
                        tooltip: None,
                        padding_left: None,
                        padding_right: None,
                        data: None,
                    }]))
                }
            })
            .next()
            .await;
        cx.foreground().run_until_parked();

        let mut edits_made = 1;
        editor.update(cx, |editor, cx| {
            let expected_hints = vec!["0".to_string()];
            assert_eq!(
                expected_hints,
                cached_hint_labels(editor),
                "Should get its first hints when opening the editor"
            );
            assert_eq!(expected_hints, visible_hint_labels(editor, cx));
            assert_eq!(
                editor.inlay_hint_cache().version,
                edits_made,
                "The editor update the cache version after every cache/view change"
            );
        });

        let progress_token = "test_progress_token";
        fake_server
            .request::<lsp::request::WorkDoneProgressCreate>(lsp::WorkDoneProgressCreateParams {
                token: lsp::ProgressToken::String(progress_token.to_string()),
            })
            .await
            .expect("work done progress create request failed");
        cx.foreground().run_until_parked();
        fake_server.notify::<lsp::notification::Progress>(lsp::ProgressParams {
            token: lsp::ProgressToken::String(progress_token.to_string()),
            value: lsp::ProgressParamsValue::WorkDone(lsp::WorkDoneProgress::Begin(
                lsp::WorkDoneProgressBegin::default(),
            )),
        });
        cx.foreground().run_until_parked();

        editor.update(cx, |editor, cx| {
            let expected_hints = vec!["0".to_string()];
            assert_eq!(
                expected_hints,
                cached_hint_labels(editor),
                "Should not update hints while the work task is running"
            );
            assert_eq!(expected_hints, visible_hint_labels(editor, cx));
            assert_eq!(
                editor.inlay_hint_cache().version,
                edits_made,
                "Should not update the cache while the work task is running"
            );
        });

        fake_server.notify::<lsp::notification::Progress>(lsp::ProgressParams {
            token: lsp::ProgressToken::String(progress_token.to_string()),
            value: lsp::ProgressParamsValue::WorkDone(lsp::WorkDoneProgress::End(
                lsp::WorkDoneProgressEnd::default(),
            )),
        });
        cx.foreground().run_until_parked();

        edits_made += 1;
        editor.update(cx, |editor, cx| {
            let expected_hints = vec!["1".to_string()];
            assert_eq!(
                expected_hints,
                cached_hint_labels(editor),
                "New hints should be queried after the work task is done"
            );
            assert_eq!(expected_hints, visible_hint_labels(editor, cx));
            assert_eq!(
                editor.inlay_hint_cache().version,
                edits_made,
                "Cache version should udpate once after the work task is done"
            );
        });
    }

    #[gpui::test]
    async fn test_no_hint_updates_for_unrelated_language_files(cx: &mut gpui::TestAppContext) {
        init_test(cx, |settings| {
            settings.defaults.inlay_hints = Some(InlayHintSettings {
                enabled: true,
                show_type_hints: true,
                show_parameter_hints: true,
                show_other_hints: true,
            })
        });

        let fs = FakeFs::new(cx.background());
        fs.insert_tree(
                    "/a",
                    json!({
                        "main.rs": "fn main() { a } // and some long comment to ensure inlays are not trimmed out",
                        "other.md": "Test md file with some text",
                    }),
                )
                .await;
        let project = Project::test(fs, ["/a".as_ref()], cx).await;
        let workspace = cx
            .add_window(|cx| Workspace::test_new(project.clone(), cx))
            .root(cx);
        let worktree_id = workspace.update(cx, |workspace, cx| {
            workspace.project().read_with(cx, |project, cx| {
                project.worktrees(cx).next().unwrap().read(cx).id()
            })
        });

        let mut rs_fake_servers = None;
        let mut md_fake_servers = None;
        for (name, path_suffix) in [("Rust", "rs"), ("Markdown", "md")] {
            let mut language = Language::new(
                LanguageConfig {
                    name: name.into(),
                    path_suffixes: vec![path_suffix.to_string()],
                    ..Default::default()
                },
                Some(tree_sitter_rust::language()),
            );
            let fake_servers = language
                .set_fake_lsp_adapter(Arc::new(FakeLspAdapter {
                    name,
                    capabilities: lsp::ServerCapabilities {
                        inlay_hint_provider: Some(lsp::OneOf::Left(true)),
                        ..Default::default()
                    },
                    ..Default::default()
                }))
                .await;
            match name {
                "Rust" => rs_fake_servers = Some(fake_servers),
                "Markdown" => md_fake_servers = Some(fake_servers),
                _ => unreachable!(),
            }
            project.update(cx, |project, _| {
                project.languages().add(Arc::new(language));
            });
        }

        let _rs_buffer = project
            .update(cx, |project, cx| {
                project.open_local_buffer("/a/main.rs", cx)
            })
            .await
            .unwrap();
        cx.foreground().run_until_parked();
        cx.foreground().start_waiting();
        let rs_fake_server = rs_fake_servers.unwrap().next().await.unwrap();
        let rs_editor = workspace
            .update(cx, |workspace, cx| {
                workspace.open_path((worktree_id, "main.rs"), None, true, cx)
            })
            .await
            .unwrap()
            .downcast::<Editor>()
            .unwrap();
        let rs_lsp_request_count = Arc::new(AtomicU32::new(0));
        rs_fake_server
            .handle_request::<lsp::request::InlayHintRequest, _, _>(move |params, _| {
                let task_lsp_request_count = Arc::clone(&rs_lsp_request_count);
                async move {
                    assert_eq!(
                        params.text_document.uri,
                        lsp::Url::from_file_path("/a/main.rs").unwrap(),
                    );
                    let i = Arc::clone(&task_lsp_request_count).fetch_add(1, Ordering::SeqCst);
                    Ok(Some(vec![lsp::InlayHint {
                        position: lsp::Position::new(0, i),
                        label: lsp::InlayHintLabel::String(i.to_string()),
                        kind: None,
                        text_edits: None,
                        tooltip: None,
                        padding_left: None,
                        padding_right: None,
                        data: None,
                    }]))
                }
            })
            .next()
            .await;
        cx.foreground().run_until_parked();
        rs_editor.update(cx, |editor, cx| {
            let expected_hints = vec!["0".to_string()];
            assert_eq!(
                expected_hints,
                cached_hint_labels(editor),
                "Should get its first hints when opening the editor"
            );
            assert_eq!(expected_hints, visible_hint_labels(editor, cx));
            assert_eq!(
                editor.inlay_hint_cache().version,
                1,
                "Rust editor update the cache version after every cache/view change"
            );
        });

        cx.foreground().run_until_parked();
        let _md_buffer = project
            .update(cx, |project, cx| {
                project.open_local_buffer("/a/other.md", cx)
            })
            .await
            .unwrap();
        cx.foreground().run_until_parked();
        cx.foreground().start_waiting();
        let md_fake_server = md_fake_servers.unwrap().next().await.unwrap();
        let md_editor = workspace
            .update(cx, |workspace, cx| {
                workspace.open_path((worktree_id, "other.md"), None, true, cx)
            })
            .await
            .unwrap()
            .downcast::<Editor>()
            .unwrap();
        let md_lsp_request_count = Arc::new(AtomicU32::new(0));
        md_fake_server
            .handle_request::<lsp::request::InlayHintRequest, _, _>(move |params, _| {
                let task_lsp_request_count = Arc::clone(&md_lsp_request_count);
                async move {
                    assert_eq!(
                        params.text_document.uri,
                        lsp::Url::from_file_path("/a/other.md").unwrap(),
                    );
                    let i = Arc::clone(&task_lsp_request_count).fetch_add(1, Ordering::SeqCst);
                    Ok(Some(vec![lsp::InlayHint {
                        position: lsp::Position::new(0, i),
                        label: lsp::InlayHintLabel::String(i.to_string()),
                        kind: None,
                        text_edits: None,
                        tooltip: None,
                        padding_left: None,
                        padding_right: None,
                        data: None,
                    }]))
                }
            })
            .next()
            .await;
        cx.foreground().run_until_parked();
        md_editor.update(cx, |editor, cx| {
            let expected_hints = vec!["0".to_string()];
            assert_eq!(
                expected_hints,
                cached_hint_labels(editor),
                "Markdown editor should have a separate verison, repeating Rust editor rules"
            );
            assert_eq!(expected_hints, visible_hint_labels(editor, cx));
            assert_eq!(editor.inlay_hint_cache().version, 1);
        });

        rs_editor.update(cx, |editor, cx| {
            editor.change_selections(None, cx, |s| s.select_ranges([13..13]));
            editor.handle_input("some rs change", cx);
        });
        cx.foreground().run_until_parked();
        rs_editor.update(cx, |editor, cx| {
            let expected_hints = vec!["1".to_string()];
            assert_eq!(
                expected_hints,
                cached_hint_labels(editor),
                "Rust inlay cache should change after the edit"
            );
            assert_eq!(expected_hints, visible_hint_labels(editor, cx));
            assert_eq!(
                editor.inlay_hint_cache().version,
                2,
                "Every time hint cache changes, cache version should be incremented"
            );
        });
        md_editor.update(cx, |editor, cx| {
            let expected_hints = vec!["0".to_string()];
            assert_eq!(
                expected_hints,
                cached_hint_labels(editor),
                "Markdown editor should not be affected by Rust editor changes"
            );
            assert_eq!(expected_hints, visible_hint_labels(editor, cx));
            assert_eq!(editor.inlay_hint_cache().version, 1);
        });

        md_editor.update(cx, |editor, cx| {
            editor.change_selections(None, cx, |s| s.select_ranges([13..13]));
            editor.handle_input("some md change", cx);
        });
        cx.foreground().run_until_parked();
        md_editor.update(cx, |editor, cx| {
            let expected_hints = vec!["1".to_string()];
            assert_eq!(
                expected_hints,
                cached_hint_labels(editor),
                "Rust editor should not be affected by Markdown editor changes"
            );
            assert_eq!(expected_hints, visible_hint_labels(editor, cx));
            assert_eq!(editor.inlay_hint_cache().version, 2);
        });
        rs_editor.update(cx, |editor, cx| {
            let expected_hints = vec!["1".to_string()];
            assert_eq!(
                expected_hints,
                cached_hint_labels(editor),
                "Markdown editor should also change independently"
            );
            assert_eq!(expected_hints, visible_hint_labels(editor, cx));
            assert_eq!(editor.inlay_hint_cache().version, 2);
        });
    }

    #[gpui::test]
    async fn test_hint_setting_changes(cx: &mut gpui::TestAppContext) {
        let allowed_hint_kinds = HashSet::from_iter([None, Some(InlayHintKind::Type)]);
        init_test(cx, |settings| {
            settings.defaults.inlay_hints = Some(InlayHintSettings {
                enabled: true,
                show_type_hints: allowed_hint_kinds.contains(&Some(InlayHintKind::Type)),
                show_parameter_hints: allowed_hint_kinds.contains(&Some(InlayHintKind::Parameter)),
                show_other_hints: allowed_hint_kinds.contains(&None),
            })
        });

        let (file_with_hints, editor, fake_server) = prepare_test_objects(cx).await;
        let lsp_request_count = Arc::new(AtomicU32::new(0));
        let another_lsp_request_count = Arc::clone(&lsp_request_count);
        fake_server
            .handle_request::<lsp::request::InlayHintRequest, _, _>(move |params, _| {
                let task_lsp_request_count = Arc::clone(&another_lsp_request_count);
                async move {
                    Arc::clone(&task_lsp_request_count).fetch_add(1, Ordering::SeqCst);
                    assert_eq!(
                        params.text_document.uri,
                        lsp::Url::from_file_path(file_with_hints).unwrap(),
                    );
                    Ok(Some(vec![
                        lsp::InlayHint {
                            position: lsp::Position::new(0, 1),
                            label: lsp::InlayHintLabel::String("type hint".to_string()),
                            kind: Some(lsp::InlayHintKind::TYPE),
                            text_edits: None,
                            tooltip: None,
                            padding_left: None,
                            padding_right: None,
                            data: None,
                        },
                        lsp::InlayHint {
                            position: lsp::Position::new(0, 2),
                            label: lsp::InlayHintLabel::String("parameter hint".to_string()),
                            kind: Some(lsp::InlayHintKind::PARAMETER),
                            text_edits: None,
                            tooltip: None,
                            padding_left: None,
                            padding_right: None,
                            data: None,
                        },
                        lsp::InlayHint {
                            position: lsp::Position::new(0, 3),
                            label: lsp::InlayHintLabel::String("other hint".to_string()),
                            kind: None,
                            text_edits: None,
                            tooltip: None,
                            padding_left: None,
                            padding_right: None,
                            data: None,
                        },
                    ]))
                }
            })
            .next()
            .await;
        cx.foreground().run_until_parked();

        let mut edits_made = 1;
        editor.update(cx, |editor, cx| {
            assert_eq!(
                lsp_request_count.load(Ordering::Relaxed),
                1,
                "Should query new hints once"
            );
            assert_eq!(
                vec![
                    "other hint".to_string(),
                    "parameter hint".to_string(),
                    "type hint".to_string(),
                ],
                cached_hint_labels(editor),
                "Should get its first hints when opening the editor"
            );
            assert_eq!(
                vec!["other hint".to_string(), "type hint".to_string()],
                visible_hint_labels(editor, cx)
            );
            let inlay_cache = editor.inlay_hint_cache();
            assert_eq!(
                inlay_cache.allowed_hint_kinds, allowed_hint_kinds,
                "Cache should use editor settings to get the allowed hint kinds"
            );
            assert_eq!(
                inlay_cache.version, edits_made,
                "The editor update the cache version after every cache/view change"
            );
        });

        fake_server
            .request::<lsp::request::InlayHintRefreshRequest>(())
            .await
            .expect("inlay refresh request failed");
        cx.foreground().run_until_parked();
        editor.update(cx, |editor, cx| {
            assert_eq!(
                lsp_request_count.load(Ordering::Relaxed),
                2,
                "Should load new hints twice"
            );
            assert_eq!(
                vec![
                    "other hint".to_string(),
                    "parameter hint".to_string(),
                    "type hint".to_string(),
                ],
                cached_hint_labels(editor),
                "Cached hints should not change due to allowed hint kinds settings update"
            );
            assert_eq!(
                vec!["other hint".to_string(), "type hint".to_string()],
                visible_hint_labels(editor, cx)
            );
            assert_eq!(
                editor.inlay_hint_cache().version,
                edits_made,
                "Should not update cache version due to new loaded hints being the same"
            );
        });

        for (new_allowed_hint_kinds, expected_visible_hints) in [
            (HashSet::from_iter([None]), vec!["other hint".to_string()]),
            (
                HashSet::from_iter([Some(InlayHintKind::Type)]),
                vec!["type hint".to_string()],
            ),
            (
                HashSet::from_iter([Some(InlayHintKind::Parameter)]),
                vec!["parameter hint".to_string()],
            ),
            (
                HashSet::from_iter([None, Some(InlayHintKind::Type)]),
                vec!["other hint".to_string(), "type hint".to_string()],
            ),
            (
                HashSet::from_iter([None, Some(InlayHintKind::Parameter)]),
                vec!["other hint".to_string(), "parameter hint".to_string()],
            ),
            (
                HashSet::from_iter([Some(InlayHintKind::Type), Some(InlayHintKind::Parameter)]),
                vec!["parameter hint".to_string(), "type hint".to_string()],
            ),
            (
                HashSet::from_iter([
                    None,
                    Some(InlayHintKind::Type),
                    Some(InlayHintKind::Parameter),
                ]),
                vec![
                    "other hint".to_string(),
                    "parameter hint".to_string(),
                    "type hint".to_string(),
                ],
            ),
        ] {
            edits_made += 1;
            update_test_language_settings(cx, |settings| {
                settings.defaults.inlay_hints = Some(InlayHintSettings {
                    enabled: true,
                    show_type_hints: new_allowed_hint_kinds.contains(&Some(InlayHintKind::Type)),
                    show_parameter_hints: new_allowed_hint_kinds
                        .contains(&Some(InlayHintKind::Parameter)),
                    show_other_hints: new_allowed_hint_kinds.contains(&None),
                })
            });
            cx.foreground().run_until_parked();
            editor.update(cx, |editor, cx| {
                assert_eq!(
                    lsp_request_count.load(Ordering::Relaxed),
                    2,
                    "Should not load new hints on allowed hint kinds change for hint kinds {new_allowed_hint_kinds:?}"
                );
                assert_eq!(
                    vec![
                        "other hint".to_string(),
                        "parameter hint".to_string(),
                        "type hint".to_string(),
                    ],
                    cached_hint_labels(editor),
                    "Should get its cached hints unchanged after the settings change for hint kinds {new_allowed_hint_kinds:?}"
                );
                assert_eq!(
                    expected_visible_hints,
                    visible_hint_labels(editor, cx),
                    "Should get its visible hints filtered after the settings change for hint kinds {new_allowed_hint_kinds:?}"
                );
                let inlay_cache = editor.inlay_hint_cache();
                assert_eq!(
                    inlay_cache.allowed_hint_kinds, new_allowed_hint_kinds,
                    "Cache should use editor settings to get the allowed hint kinds for hint kinds {new_allowed_hint_kinds:?}"
                );
                assert_eq!(
                    inlay_cache.version, edits_made,
                    "The editor should update the cache version after every cache/view change for hint kinds {new_allowed_hint_kinds:?} due to visible hints change"
                );
            });
        }

        edits_made += 1;
        let another_allowed_hint_kinds = HashSet::from_iter([Some(InlayHintKind::Type)]);
        update_test_language_settings(cx, |settings| {
            settings.defaults.inlay_hints = Some(InlayHintSettings {
                enabled: false,
                show_type_hints: another_allowed_hint_kinds.contains(&Some(InlayHintKind::Type)),
                show_parameter_hints: another_allowed_hint_kinds
                    .contains(&Some(InlayHintKind::Parameter)),
                show_other_hints: another_allowed_hint_kinds.contains(&None),
            })
        });
        cx.foreground().run_until_parked();
        editor.update(cx, |editor, cx| {
            assert_eq!(
                lsp_request_count.load(Ordering::Relaxed),
                2,
                "Should not load new hints when hints got disabled"
            );
            assert!(
                cached_hint_labels(editor).is_empty(),
                "Should clear the cache when hints got disabled"
            );
            assert!(
                visible_hint_labels(editor, cx).is_empty(),
                "Should clear visible hints when hints got disabled"
            );
            let inlay_cache = editor.inlay_hint_cache();
            assert_eq!(
                inlay_cache.allowed_hint_kinds, another_allowed_hint_kinds,
                "Should update its allowed hint kinds even when hints got disabled"
            );
            assert_eq!(
                inlay_cache.version, edits_made,
                "The editor should update the cache version after hints got disabled"
            );
        });

        fake_server
            .request::<lsp::request::InlayHintRefreshRequest>(())
            .await
            .expect("inlay refresh request failed");
        cx.foreground().run_until_parked();
        editor.update(cx, |editor, cx| {
            assert_eq!(
                lsp_request_count.load(Ordering::Relaxed),
                2,
                "Should not load new hints when they got disabled"
            );
            assert!(cached_hint_labels(editor).is_empty());
            assert!(visible_hint_labels(editor, cx).is_empty());
            assert_eq!(
                editor.inlay_hint_cache().version, edits_made,
                "The editor should not update the cache version after /refresh query without updates"
            );
        });

        let final_allowed_hint_kinds = HashSet::from_iter([Some(InlayHintKind::Parameter)]);
        edits_made += 1;
        update_test_language_settings(cx, |settings| {
            settings.defaults.inlay_hints = Some(InlayHintSettings {
                enabled: true,
                show_type_hints: final_allowed_hint_kinds.contains(&Some(InlayHintKind::Type)),
                show_parameter_hints: final_allowed_hint_kinds
                    .contains(&Some(InlayHintKind::Parameter)),
                show_other_hints: final_allowed_hint_kinds.contains(&None),
            })
        });
        cx.foreground().run_until_parked();
        editor.update(cx, |editor, cx| {
            assert_eq!(
                lsp_request_count.load(Ordering::Relaxed),
                3,
                "Should query for new hints when they got reenabled"
            );
            assert_eq!(
                vec![
                    "other hint".to_string(),
                    "parameter hint".to_string(),
                    "type hint".to_string(),
                ],
                cached_hint_labels(editor),
                "Should get its cached hints fully repopulated after the hints got reenabled"
            );
            assert_eq!(
                vec!["parameter hint".to_string()],
                visible_hint_labels(editor, cx),
                "Should get its visible hints repopulated and filtered after the h"
            );
            let inlay_cache = editor.inlay_hint_cache();
            assert_eq!(
                inlay_cache.allowed_hint_kinds, final_allowed_hint_kinds,
                "Cache should update editor settings when hints got reenabled"
            );
            assert_eq!(
                inlay_cache.version, edits_made,
                "Cache should update its version after hints got reenabled"
            );
        });

        fake_server
            .request::<lsp::request::InlayHintRefreshRequest>(())
            .await
            .expect("inlay refresh request failed");
        cx.foreground().run_until_parked();
        editor.update(cx, |editor, cx| {
            assert_eq!(
                lsp_request_count.load(Ordering::Relaxed),
                4,
                "Should query for new hints again"
            );
            assert_eq!(
                vec![
                    "other hint".to_string(),
                    "parameter hint".to_string(),
                    "type hint".to_string(),
                ],
                cached_hint_labels(editor),
            );
            assert_eq!(
                vec!["parameter hint".to_string()],
                visible_hint_labels(editor, cx),
            );
            assert_eq!(editor.inlay_hint_cache().version, edits_made);
        });
    }

    #[gpui::test]
    async fn test_hint_request_cancellation(cx: &mut gpui::TestAppContext) {
        init_test(cx, |settings| {
            settings.defaults.inlay_hints = Some(InlayHintSettings {
                enabled: true,
                show_type_hints: true,
                show_parameter_hints: true,
                show_other_hints: true,
            })
        });

        let (file_with_hints, editor, fake_server) = prepare_test_objects(cx).await;
        let fake_server = Arc::new(fake_server);
        let lsp_request_count = Arc::new(AtomicU32::new(0));
        let another_lsp_request_count = Arc::clone(&lsp_request_count);
        fake_server
            .handle_request::<lsp::request::InlayHintRequest, _, _>(move |params, _| {
                let task_lsp_request_count = Arc::clone(&another_lsp_request_count);
                async move {
                    let i = Arc::clone(&task_lsp_request_count).fetch_add(1, Ordering::SeqCst) + 1;
                    assert_eq!(
                        params.text_document.uri,
                        lsp::Url::from_file_path(file_with_hints).unwrap(),
                    );
                    Ok(Some(vec![lsp::InlayHint {
                        position: lsp::Position::new(0, i),
                        label: lsp::InlayHintLabel::String(i.to_string()),
                        kind: None,
                        text_edits: None,
                        tooltip: None,
                        padding_left: None,
                        padding_right: None,
                        data: None,
                    }]))
                }
            })
            .next()
            .await;

        let mut expected_changes = Vec::new();
        for change_after_opening in [
            "initial change #1",
            "initial change #2",
            "initial change #3",
        ] {
            editor.update(cx, |editor, cx| {
                editor.change_selections(None, cx, |s| s.select_ranges([13..13]));
                editor.handle_input(change_after_opening, cx);
            });
            expected_changes.push(change_after_opening);
        }

        cx.foreground().run_until_parked();

        editor.update(cx, |editor, cx| {
            let current_text = editor.text(cx);
            for change in &expected_changes {
                assert!(
                    current_text.contains(change),
                    "Should apply all changes made"
                );
            }
            assert_eq!(
                lsp_request_count.load(Ordering::Relaxed),
                2,
                "Should query new hints twice: for editor init and for the last edit that interrupted all others"
            );
            let expected_hints = vec!["2".to_string()];
            assert_eq!(
                expected_hints,
                cached_hint_labels(editor),
                "Should get hints from the last edit landed only"
            );
            assert_eq!(expected_hints, visible_hint_labels(editor, cx));
            assert_eq!(
                editor.inlay_hint_cache().version, 1,
                "Only one update should be registered in the cache after all cancellations"
            );
        });

        let mut edits = Vec::new();
        for async_later_change in [
            "another change #1",
            "another change #2",
            "another change #3",
        ] {
            expected_changes.push(async_later_change);
            let task_editor = editor.clone();
            let mut task_cx = cx.clone();
            edits.push(cx.foreground().spawn(async move {
                task_editor.update(&mut task_cx, |editor, cx| {
                    editor.change_selections(None, cx, |s| s.select_ranges([13..13]));
                    editor.handle_input(async_later_change, cx);
                });
            }));
        }
        let _ = future::join_all(edits).await;
        cx.foreground().run_until_parked();

        editor.update(cx, |editor, cx| {
            let current_text = editor.text(cx);
            for change in &expected_changes {
                assert!(
                    current_text.contains(change),
                    "Should apply all changes made"
                );
            }
            assert_eq!(
                lsp_request_count.load(Ordering::SeqCst),
                3,
                "Should query new hints one more time, for the last edit only"
            );
            let expected_hints = vec!["3".to_string()];
            assert_eq!(
                expected_hints,
                cached_hint_labels(editor),
                "Should get hints from the last edit landed only"
            );
            assert_eq!(expected_hints, visible_hint_labels(editor, cx));
            assert_eq!(
                editor.inlay_hint_cache().version,
                2,
                "Should update the cache version once more, for the new change"
            );
        });
    }

    #[gpui::test]
    async fn test_large_buffer_inlay_requests_split(cx: &mut gpui::TestAppContext) {
        init_test(cx, |settings| {
            settings.defaults.inlay_hints = Some(InlayHintSettings {
                enabled: true,
                show_type_hints: true,
                show_parameter_hints: true,
                show_other_hints: true,
            })
        });

        let mut language = Language::new(
            LanguageConfig {
                name: "Rust".into(),
                path_suffixes: vec!["rs".to_string()],
                ..Default::default()
            },
            Some(tree_sitter_rust::language()),
        );
        let mut fake_servers = language
            .set_fake_lsp_adapter(Arc::new(FakeLspAdapter {
                capabilities: lsp::ServerCapabilities {
                    inlay_hint_provider: Some(lsp::OneOf::Left(true)),
                    ..Default::default()
                },
                ..Default::default()
            }))
            .await;
        let fs = FakeFs::new(cx.background());
        fs.insert_tree(
            "/a",
            json!({
                "main.rs": format!("fn main() {{\n{}\n}}", "let i = 5;\n".repeat(500)),
                "other.rs": "// Test file",
            }),
        )
        .await;
        let project = Project::test(fs, ["/a".as_ref()], cx).await;
        project.update(cx, |project, _| project.languages().add(Arc::new(language)));
        let workspace = cx
            .add_window(|cx| Workspace::test_new(project.clone(), cx))
            .root(cx);
        let worktree_id = workspace.update(cx, |workspace, cx| {
            workspace.project().read_with(cx, |project, cx| {
                project.worktrees(cx).next().unwrap().read(cx).id()
            })
        });

        let _buffer = project
            .update(cx, |project, cx| {
                project.open_local_buffer("/a/main.rs", cx)
            })
            .await
            .unwrap();
        cx.foreground().run_until_parked();
        cx.foreground().start_waiting();
        let fake_server = fake_servers.next().await.unwrap();
        let editor = workspace
            .update(cx, |workspace, cx| {
                workspace.open_path((worktree_id, "main.rs"), None, true, cx)
            })
            .await
            .unwrap()
            .downcast::<Editor>()
            .unwrap();
        let lsp_request_ranges = Arc::new(Mutex::new(Vec::new()));
        let lsp_request_count = Arc::new(AtomicUsize::new(0));
        let closure_lsp_request_ranges = Arc::clone(&lsp_request_ranges);
        let closure_lsp_request_count = Arc::clone(&lsp_request_count);
        fake_server
            .handle_request::<lsp::request::InlayHintRequest, _, _>(move |params, _| {
                let task_lsp_request_ranges = Arc::clone(&closure_lsp_request_ranges);
                let task_lsp_request_count = Arc::clone(&closure_lsp_request_count);
                async move {
                    assert_eq!(
                        params.text_document.uri,
                        lsp::Url::from_file_path("/a/main.rs").unwrap(),
                    );

                    task_lsp_request_ranges.lock().push(params.range);
                    let i = Arc::clone(&task_lsp_request_count).fetch_add(1, Ordering::Release) + 1;
                    Ok(Some(vec![lsp::InlayHint {
                        position: params.range.end,
                        label: lsp::InlayHintLabel::String(i.to_string()),
                        kind: None,
                        text_edits: None,
                        tooltip: None,
                        padding_left: None,
                        padding_right: None,
                        data: None,
                    }]))
                }
            })
            .next()
            .await;
        fn editor_visible_range(
            editor: &ViewHandle<Editor>,
            cx: &mut gpui::TestAppContext,
        ) -> Range<Point> {
            let ranges = editor.update(cx, |editor, cx| editor.excerpt_visible_offsets(None, cx));
            assert_eq!(
                ranges.len(),
                1,
                "Single buffer should produce a single excerpt with visible range"
            );
            let (_, (excerpt_buffer, _, excerpt_visible_range)) =
                ranges.into_iter().next().unwrap();
            excerpt_buffer.update(cx, |buffer, _| {
                let snapshot = buffer.snapshot();
                let start = buffer
                    .anchor_before(excerpt_visible_range.start)
                    .to_point(&snapshot);
                let end = buffer
                    .anchor_after(excerpt_visible_range.end)
                    .to_point(&snapshot);
                start..end
            })
        }

        // in large buffers, requests are made for more than visible range of a buffer.
        // invisible parts are queried later, to avoid excessive requests on quick typing.
        // wait the timeout needed to get all requests.
        cx.foreground().advance_clock(Duration::from_millis(
            INVISIBLE_RANGES_HINTS_REQUEST_DELAY_MILLIS + 100,
        ));
        cx.foreground().run_until_parked();
        let initial_visible_range = editor_visible_range(&editor, cx);
        let lsp_initial_visible_range = lsp::Range::new(
            lsp::Position::new(
                initial_visible_range.start.row,
                initial_visible_range.start.column,
            ),
            lsp::Position::new(
                initial_visible_range.end.row,
                initial_visible_range.end.column,
            ),
        );
        let expected_initial_query_range_end =
            lsp::Position::new(initial_visible_range.end.row * 2, 2);
        let mut expected_invisible_query_start = lsp_initial_visible_range.end;
        expected_invisible_query_start.character += 1;
        editor.update(cx, |editor, cx| {
            let ranges = lsp_request_ranges.lock().drain(..).collect::<Vec<_>>();
            assert_eq!(ranges.len(), 2,
                "When scroll is at the edge of a big document, its visible part and the same range further should be queried in order, but got: {ranges:?}");
            let visible_query_range = &ranges[0];
            assert_eq!(visible_query_range.start, lsp_initial_visible_range.start);
            assert_eq!(visible_query_range.end, lsp_initial_visible_range.end);
            let invisible_query_range = &ranges[1];

            assert_eq!(invisible_query_range.start, expected_invisible_query_start, "Should initially query visible edge of the document");
            assert_eq!(invisible_query_range.end, expected_initial_query_range_end, "Should initially query visible edge of the document");

            let requests_count = lsp_request_count.load(Ordering::Acquire);
            assert_eq!(requests_count, 2, "Visible + invisible request");
            let expected_hints = vec!["1".to_string(), "2".to_string()];
            assert_eq!(
                expected_hints,
                cached_hint_labels(editor),
                "Should have hints from both LSP requests made for a big file"
            );
            assert_eq!(expected_hints, visible_hint_labels(editor, cx), "Should display only hints from the visible range");
            assert_eq!(
                editor.inlay_hint_cache().version, requests_count,
                "LSP queries should've bumped the cache version"
            );
        });

        editor.update(cx, |editor, cx| {
            editor.scroll_screen(&ScrollAmount::Page(1.0), cx);
            editor.scroll_screen(&ScrollAmount::Page(1.0), cx);
        });
        cx.foreground().advance_clock(Duration::from_millis(
            INVISIBLE_RANGES_HINTS_REQUEST_DELAY_MILLIS + 100,
        ));
        cx.foreground().run_until_parked();
        let visible_range_after_scrolls = editor_visible_range(&editor, cx);
        let visible_line_count =
            editor.update(cx, |editor, _| editor.visible_line_count().unwrap());
        let selection_in_cached_range = editor.update(cx, |editor, cx| {
            let ranges = lsp_request_ranges
                .lock()
                .drain(..)
                .sorted_by_key(|r| r.start)
                .collect::<Vec<_>>();
            assert_eq!(
                ranges.len(),
                2,
                "Should query 2 ranges after both scrolls, but got: {ranges:?}"
            );
            let first_scroll = &ranges[0];
            let second_scroll = &ranges[1];
            assert_eq!(
                first_scroll.end, second_scroll.start,
                "Should query 2 adjacent ranges after the scrolls, but got: {ranges:?}"
            );
            assert_eq!(
                first_scroll.start, expected_initial_query_range_end,
                "First scroll should start the query right after the end of the original scroll",
            );
            assert_eq!(
                second_scroll.end,
                lsp::Position::new(
                    visible_range_after_scrolls.end.row
                        + visible_line_count.ceil() as u32,
                    1,
                ),
                "Second scroll should query one more screen down after the end of the visible range"
            );

            let lsp_requests = lsp_request_count.load(Ordering::Acquire);
            assert_eq!(lsp_requests, 4, "Should query for hints after every scroll");
            let expected_hints = vec![
                "1".to_string(),
                "2".to_string(),
                "3".to_string(),
                "4".to_string(),
            ];
            assert_eq!(
                expected_hints,
                cached_hint_labels(editor),
                "Should have hints from the new LSP response after the edit"
            );
            assert_eq!(expected_hints, visible_hint_labels(editor, cx));
            assert_eq!(
                editor.inlay_hint_cache().version,
                lsp_requests,
                "Should update the cache for every LSP response with hints added"
            );

            let mut selection_in_cached_range = visible_range_after_scrolls.end;
            selection_in_cached_range.row -= visible_line_count.ceil() as u32;
            selection_in_cached_range
        });

        editor.update(cx, |editor, cx| {
            editor.change_selections(Some(Autoscroll::center()), cx, |s| {
                s.select_ranges([selection_in_cached_range..selection_in_cached_range])
            });
        });
        cx.foreground().advance_clock(Duration::from_millis(
            INVISIBLE_RANGES_HINTS_REQUEST_DELAY_MILLIS + 100,
        ));
        cx.foreground().run_until_parked();
        editor.update(cx, |_, _| {
            let ranges = lsp_request_ranges
                .lock()
                .drain(..)
                .sorted_by_key(|r| r.start)
                .collect::<Vec<_>>();
            assert!(ranges.is_empty(), "No new ranges or LSP queries should be made after returning to the selection with cached hints");
            assert_eq!(lsp_request_count.load(Ordering::Acquire), 4);
        });

        editor.update(cx, |editor, cx| {
            editor.handle_input("++++more text++++", cx);
        });
        cx.foreground().advance_clock(Duration::from_millis(
            INVISIBLE_RANGES_HINTS_REQUEST_DELAY_MILLIS + 100,
        ));
        cx.foreground().run_until_parked();
        editor.update(cx, |editor, cx| {
            let ranges = lsp_request_ranges.lock().drain(..).collect::<Vec<_>>();
            assert_eq!(ranges.len(), 3,
                "On edit, should scroll to selection and query a range around it: visible + same range above and below. Instead, got query ranges {ranges:?}");
            let visible_query_range = &ranges[0];
            let above_query_range = &ranges[1];
            let below_query_range = &ranges[2];
            assert!(above_query_range.end.character < visible_query_range.start.character || above_query_range.end.line + 1 == visible_query_range.start.line,
                "Above range {above_query_range:?} should be before visible range {visible_query_range:?}");
            assert!(visible_query_range.end.character < below_query_range.start.character || visible_query_range.end.line  + 1 == below_query_range.start.line,
                "Visible range {visible_query_range:?} should be before below range {below_query_range:?}");
            assert!(above_query_range.start.line < selection_in_cached_range.row,
                "Hints should be queried with the selected range after the query range start");
            assert!(below_query_range.end.line > selection_in_cached_range.row,
                "Hints should be queried with the selected range before the query range end");
            assert!(above_query_range.start.line <= selection_in_cached_range.row - (visible_line_count * 3.0 / 2.0) as u32,
                "Hints query range should contain one more screen before");
            assert!(below_query_range.end.line >= selection_in_cached_range.row + (visible_line_count * 3.0 / 2.0) as u32,
                "Hints query range should contain one more screen after");

            let lsp_requests = lsp_request_count.load(Ordering::Acquire);
            assert_eq!(lsp_requests, 7, "There should be a visible range and two ranges above and below it queried");
            let expected_hints = vec!["5".to_string(), "6".to_string(), "7".to_string()];
            assert_eq!(expected_hints, cached_hint_labels(editor),
                "Should have hints from the new LSP response after the edit");
            assert_eq!(expected_hints, visible_hint_labels(editor, cx));
            assert_eq!(editor.inlay_hint_cache().version, lsp_requests, "Should update the cache for every LSP response with hints added");
        });
    }

    #[gpui::test(iterations = 10)]
    async fn test_multiple_excerpts_large_multibuffer(
        deterministic: Arc<Deterministic>,
        cx: &mut gpui::TestAppContext,
    ) {
        init_test(cx, |settings| {
            settings.defaults.inlay_hints = Some(InlayHintSettings {
                enabled: true,
                show_type_hints: true,
                show_parameter_hints: true,
                show_other_hints: true,
            })
        });

        let mut language = Language::new(
            LanguageConfig {
                name: "Rust".into(),
                path_suffixes: vec!["rs".to_string()],
                ..Default::default()
            },
            Some(tree_sitter_rust::language()),
        );
        let mut fake_servers = language
            .set_fake_lsp_adapter(Arc::new(FakeLspAdapter {
                capabilities: lsp::ServerCapabilities {
                    inlay_hint_provider: Some(lsp::OneOf::Left(true)),
                    ..Default::default()
                },
                ..Default::default()
            }))
            .await;
        let language = Arc::new(language);
        let fs = FakeFs::new(cx.background());
        fs.insert_tree(
            "/a",
            json!({
                "main.rs": format!("fn main() {{\n{}\n}}", (0..501).map(|i| format!("let i = {i};\n")).collect::<Vec<_>>().join("")),
                "other.rs": format!("fn main() {{\n{}\n}}", (0..501).map(|j| format!("let j = {j};\n")).collect::<Vec<_>>().join("")),
            }),
        )
        .await;
        let project = Project::test(fs, ["/a".as_ref()], cx).await;
        project.update(cx, |project, _| {
            project.languages().add(Arc::clone(&language))
        });
        let workspace = cx
            .add_window(|cx| Workspace::test_new(project.clone(), cx))
            .root(cx);
        let worktree_id = workspace.update(cx, |workspace, cx| {
            workspace.project().read_with(cx, |project, cx| {
                project.worktrees(cx).next().unwrap().read(cx).id()
            })
        });

        let buffer_1 = project
            .update(cx, |project, cx| {
                project.open_buffer((worktree_id, "main.rs"), cx)
            })
            .await
            .unwrap();
        let buffer_2 = project
            .update(cx, |project, cx| {
                project.open_buffer((worktree_id, "other.rs"), cx)
            })
            .await
            .unwrap();
        let multibuffer = cx.add_model(|cx| {
            let mut multibuffer = MultiBuffer::new(0);
            multibuffer.push_excerpts(
                buffer_1.clone(),
                [
                    ExcerptRange {
                        context: Point::new(0, 0)..Point::new(2, 0),
                        primary: None,
                    },
                    ExcerptRange {
                        context: Point::new(4, 0)..Point::new(11, 0),
                        primary: None,
                    },
                    ExcerptRange {
                        context: Point::new(22, 0)..Point::new(33, 0),
                        primary: None,
                    },
                    ExcerptRange {
                        context: Point::new(44, 0)..Point::new(55, 0),
                        primary: None,
                    },
                    ExcerptRange {
                        context: Point::new(56, 0)..Point::new(66, 0),
                        primary: None,
                    },
                    ExcerptRange {
                        context: Point::new(67, 0)..Point::new(77, 0),
                        primary: None,
                    },
                ],
                cx,
            );
            multibuffer.push_excerpts(
                buffer_2.clone(),
                [
                    ExcerptRange {
                        context: Point::new(0, 1)..Point::new(2, 1),
                        primary: None,
                    },
                    ExcerptRange {
                        context: Point::new(4, 1)..Point::new(11, 1),
                        primary: None,
                    },
                    ExcerptRange {
                        context: Point::new(22, 1)..Point::new(33, 1),
                        primary: None,
                    },
                    ExcerptRange {
                        context: Point::new(44, 1)..Point::new(55, 1),
                        primary: None,
                    },
                    ExcerptRange {
                        context: Point::new(56, 1)..Point::new(66, 1),
                        primary: None,
                    },
                    ExcerptRange {
                        context: Point::new(67, 1)..Point::new(77, 1),
                        primary: None,
                    },
                ],
                cx,
            );
            multibuffer
        });

        deterministic.run_until_parked();
        cx.foreground().run_until_parked();
        let editor = cx
            .add_window(|cx| Editor::for_multibuffer(multibuffer, Some(project.clone()), cx))
            .root(cx);
        let editor_edited = Arc::new(AtomicBool::new(false));
        let fake_server = fake_servers.next().await.unwrap();
        let closure_editor_edited = Arc::clone(&editor_edited);
        fake_server
            .handle_request::<lsp::request::InlayHintRequest, _, _>(move |params, _| {
                let task_editor_edited = Arc::clone(&closure_editor_edited);
                async move {
                    let hint_text = if params.text_document.uri
                        == lsp::Url::from_file_path("/a/main.rs").unwrap()
                    {
                        "main hint"
                    } else if params.text_document.uri
                        == lsp::Url::from_file_path("/a/other.rs").unwrap()
                    {
                        "other hint"
                    } else {
                        panic!("unexpected uri: {:?}", params.text_document.uri);
                    };

                    // one hint per excerpt
                    let positions = [
                        lsp::Position::new(0, 2),
                        lsp::Position::new(4, 2),
                        lsp::Position::new(22, 2),
                        lsp::Position::new(44, 2),
                        lsp::Position::new(56, 2),
                        lsp::Position::new(67, 2),
                    ];
                    let out_of_range_hint = lsp::InlayHint {
                        position: lsp::Position::new(
                            params.range.start.line + 99,
                            params.range.start.character + 99,
                        ),
                        label: lsp::InlayHintLabel::String(
                            "out of excerpt range, should be ignored".to_string(),
                        ),
                        kind: None,
                        text_edits: None,
                        tooltip: None,
                        padding_left: None,
                        padding_right: None,
                        data: None,
                    };

                    let edited = task_editor_edited.load(Ordering::Acquire);
                    Ok(Some(
                        std::iter::once(out_of_range_hint)
                            .chain(positions.into_iter().enumerate().map(|(i, position)| {
                                lsp::InlayHint {
                                    position,
                                    label: lsp::InlayHintLabel::String(format!(
                                        "{hint_text}{} #{i}",
                                        if edited { "(edited)" } else { "" },
                                    )),
                                    kind: None,
                                    text_edits: None,
                                    tooltip: None,
                                    padding_left: None,
                                    padding_right: None,
                                    data: None,
                                }
                            }))
                            .collect(),
                    ))
                }
            })
            .next()
            .await;
        cx.foreground().run_until_parked();

        editor.update(cx, |editor, cx| {
            let expected_hints = vec![
                "main hint #0".to_string(),
                "main hint #1".to_string(),
                "main hint #2".to_string(),
                "main hint #3".to_string(),
            ];
            assert_eq!(
                expected_hints,
                cached_hint_labels(editor),
                "When scroll is at the edge of a multibuffer, its visible excerpts only should be queried for inlay hints"
            );
            assert_eq!(expected_hints, visible_hint_labels(editor, cx));
            assert_eq!(editor.inlay_hint_cache().version, expected_hints.len(), "Every visible excerpt hints should bump the verison");
        });

        editor.update(cx, |editor, cx| {
            editor.change_selections(Some(Autoscroll::Next), cx, |s| {
                s.select_ranges([Point::new(4, 0)..Point::new(4, 0)])
            });
            editor.change_selections(Some(Autoscroll::Next), cx, |s| {
                s.select_ranges([Point::new(22, 0)..Point::new(22, 0)])
            });
            editor.change_selections(Some(Autoscroll::Next), cx, |s| {
                s.select_ranges([Point::new(50, 0)..Point::new(50, 0)])
            });
        });
        cx.foreground().run_until_parked();
        editor.update(cx, |editor, cx| {
            let expected_hints = vec![
                "main hint #0".to_string(),
                "main hint #1".to_string(),
                "main hint #2".to_string(),
                "main hint #3".to_string(),
                "main hint #4".to_string(),
                "main hint #5".to_string(),
                "other hint #0".to_string(),
                "other hint #1".to_string(),
                "other hint #2".to_string(),
            ];
            assert_eq!(expected_hints, cached_hint_labels(editor),
                "With more scrolls of the multibuffer, more hints should be added into the cache and nothing invalidated without edits");
            assert_eq!(expected_hints, visible_hint_labels(editor, cx));
            assert_eq!(editor.inlay_hint_cache().version, expected_hints.len(),
                "Due to every excerpt having one hint, we update cache per new excerpt scrolled");
        });

        editor.update(cx, |editor, cx| {
            editor.change_selections(Some(Autoscroll::Next), cx, |s| {
                s.select_ranges([Point::new(100, 0)..Point::new(100, 0)])
            });
        });
        cx.foreground().advance_clock(Duration::from_millis(
            INVISIBLE_RANGES_HINTS_REQUEST_DELAY_MILLIS + 100,
        ));
        cx.foreground().run_until_parked();
        let last_scroll_update_version = editor.update(cx, |editor, cx| {
            let expected_hints = vec![
                "main hint #0".to_string(),
                "main hint #1".to_string(),
                "main hint #2".to_string(),
                "main hint #3".to_string(),
                "main hint #4".to_string(),
                "main hint #5".to_string(),
                "other hint #0".to_string(),
                "other hint #1".to_string(),
                "other hint #2".to_string(),
                "other hint #3".to_string(),
                "other hint #4".to_string(),
                "other hint #5".to_string(),
            ];
            assert_eq!(expected_hints, cached_hint_labels(editor),
                "After multibuffer was scrolled to the end, all hints for all excerpts should be fetched");
            assert_eq!(expected_hints, visible_hint_labels(editor, cx));
            assert_eq!(editor.inlay_hint_cache().version, expected_hints.len());
            expected_hints.len()
        });

        editor.update(cx, |editor, cx| {
            editor.change_selections(Some(Autoscroll::Next), cx, |s| {
                s.select_ranges([Point::new(4, 0)..Point::new(4, 0)])
            });
        });
        cx.foreground().run_until_parked();
        editor.update(cx, |editor, cx| {
            let expected_hints = vec![
                "main hint #0".to_string(),
                "main hint #1".to_string(),
                "main hint #2".to_string(),
                "main hint #3".to_string(),
                "main hint #4".to_string(),
                "main hint #5".to_string(),
                "other hint #0".to_string(),
                "other hint #1".to_string(),
                "other hint #2".to_string(),
                "other hint #3".to_string(),
                "other hint #4".to_string(),
                "other hint #5".to_string(),
            ];
            assert_eq!(expected_hints, cached_hint_labels(editor),
                "After multibuffer was scrolled to the end, further scrolls up should not bring more hints");
            assert_eq!(expected_hints, visible_hint_labels(editor, cx));
            assert_eq!(editor.inlay_hint_cache().version, last_scroll_update_version, "No updates should happen during scrolling already scolled buffer");
        });

        editor_edited.store(true, Ordering::Release);
        editor.update(cx, |editor, cx| {
            editor.change_selections(None, cx, |s| {
                s.select_ranges([Point::new(56, 0)..Point::new(56, 0)])
            });
            editor.handle_input("++++more text++++", cx);
        });
        cx.foreground().run_until_parked();
        editor.update(cx, |editor, cx| {
            let expected_hints = vec![
                "main hint(edited) #0".to_string(),
                "main hint(edited) #1".to_string(),
                "main hint(edited) #2".to_string(),
                "main hint(edited) #3".to_string(),
                "main hint(edited) #4".to_string(),
                "main hint(edited) #5".to_string(),
                "other hint(edited) #0".to_string(),
                "other hint(edited) #1".to_string(),
            ];
            assert_eq!(
                expected_hints,
                cached_hint_labels(editor),
                "After multibuffer edit, editor gets scolled back to the last selection; \
all hints should be invalidated and requeried for all of its visible excerpts"
            );
            assert_eq!(expected_hints, visible_hint_labels(editor, cx));

            let current_cache_version = editor.inlay_hint_cache().version;
            let minimum_expected_version = last_scroll_update_version + expected_hints.len();
            assert!(
                current_cache_version == minimum_expected_version || current_cache_version == minimum_expected_version + 1,
                "Due to every excerpt having one hint, cache should update per new excerpt received + 1 potential sporadic update"
            );
        });
    }

    #[gpui::test]
    async fn test_excerpts_removed(
        deterministic: Arc<Deterministic>,
        cx: &mut gpui::TestAppContext,
    ) {
        init_test(cx, |settings| {
            settings.defaults.inlay_hints = Some(InlayHintSettings {
                enabled: true,
                show_type_hints: false,
                show_parameter_hints: false,
                show_other_hints: false,
            })
        });

        let mut language = Language::new(
            LanguageConfig {
                name: "Rust".into(),
                path_suffixes: vec!["rs".to_string()],
                ..Default::default()
            },
            Some(tree_sitter_rust::language()),
        );
        let mut fake_servers = language
            .set_fake_lsp_adapter(Arc::new(FakeLspAdapter {
                capabilities: lsp::ServerCapabilities {
                    inlay_hint_provider: Some(lsp::OneOf::Left(true)),
                    ..Default::default()
                },
                ..Default::default()
            }))
            .await;
        let language = Arc::new(language);
        let fs = FakeFs::new(cx.background());
        fs.insert_tree(
            "/a",
            json!({
                "main.rs": format!("fn main() {{\n{}\n}}", (0..501).map(|i| format!("let i = {i};\n")).collect::<Vec<_>>().join("")),
                "other.rs": format!("fn main() {{\n{}\n}}", (0..501).map(|j| format!("let j = {j};\n")).collect::<Vec<_>>().join("")),
            }),
        )
        .await;
        let project = Project::test(fs, ["/a".as_ref()], cx).await;
        project.update(cx, |project, _| {
            project.languages().add(Arc::clone(&language))
        });
        let workspace = cx
            .add_window(|cx| Workspace::test_new(project.clone(), cx))
            .root(cx);
        let worktree_id = workspace.update(cx, |workspace, cx| {
            workspace.project().read_with(cx, |project, cx| {
                project.worktrees(cx).next().unwrap().read(cx).id()
            })
        });

        let buffer_1 = project
            .update(cx, |project, cx| {
                project.open_buffer((worktree_id, "main.rs"), cx)
            })
            .await
            .unwrap();
        let buffer_2 = project
            .update(cx, |project, cx| {
                project.open_buffer((worktree_id, "other.rs"), cx)
            })
            .await
            .unwrap();
        let multibuffer = cx.add_model(|_| MultiBuffer::new(0));
        let (buffer_1_excerpts, buffer_2_excerpts) = multibuffer.update(cx, |multibuffer, cx| {
            let buffer_1_excerpts = multibuffer.push_excerpts(
                buffer_1.clone(),
                [ExcerptRange {
                    context: Point::new(0, 0)..Point::new(2, 0),
                    primary: None,
                }],
                cx,
            );
            let buffer_2_excerpts = multibuffer.push_excerpts(
                buffer_2.clone(),
                [ExcerptRange {
                    context: Point::new(0, 1)..Point::new(2, 1),
                    primary: None,
                }],
                cx,
            );
            (buffer_1_excerpts, buffer_2_excerpts)
        });

        assert!(!buffer_1_excerpts.is_empty());
        assert!(!buffer_2_excerpts.is_empty());

        deterministic.run_until_parked();
        cx.foreground().run_until_parked();
        let editor = cx
            .add_window(|cx| Editor::for_multibuffer(multibuffer, Some(project.clone()), cx))
            .root(cx);
        let editor_edited = Arc::new(AtomicBool::new(false));
        let fake_server = fake_servers.next().await.unwrap();
        let closure_editor_edited = Arc::clone(&editor_edited);
        fake_server
            .handle_request::<lsp::request::InlayHintRequest, _, _>(move |params, _| {
                let task_editor_edited = Arc::clone(&closure_editor_edited);
                async move {
                    let hint_text = if params.text_document.uri
                        == lsp::Url::from_file_path("/a/main.rs").unwrap()
                    {
                        "main hint"
                    } else if params.text_document.uri
                        == lsp::Url::from_file_path("/a/other.rs").unwrap()
                    {
                        "other hint"
                    } else {
                        panic!("unexpected uri: {:?}", params.text_document.uri);
                    };

                    let positions = [
                        lsp::Position::new(0, 2),
                        lsp::Position::new(4, 2),
                        lsp::Position::new(22, 2),
                        lsp::Position::new(44, 2),
                        lsp::Position::new(56, 2),
                        lsp::Position::new(67, 2),
                    ];
                    let out_of_range_hint = lsp::InlayHint {
                        position: lsp::Position::new(
                            params.range.start.line + 99,
                            params.range.start.character + 99,
                        ),
                        label: lsp::InlayHintLabel::String(
                            "out of excerpt range, should be ignored".to_string(),
                        ),
                        kind: None,
                        text_edits: None,
                        tooltip: None,
                        padding_left: None,
                        padding_right: None,
                        data: None,
                    };

                    let edited = task_editor_edited.load(Ordering::Acquire);
                    Ok(Some(
                        std::iter::once(out_of_range_hint)
                            .chain(positions.into_iter().enumerate().map(|(i, position)| {
                                lsp::InlayHint {
                                    position,
                                    label: lsp::InlayHintLabel::String(format!(
                                        "{hint_text}{} #{i}",
                                        if edited { "(edited)" } else { "" },
                                    )),
                                    kind: None,
                                    text_edits: None,
                                    tooltip: None,
                                    padding_left: None,
                                    padding_right: None,
                                    data: None,
                                }
                            }))
                            .collect(),
                    ))
                }
            })
            .next()
            .await;
        cx.foreground().run_until_parked();

        editor.update(cx, |editor, cx| {
            assert_eq!(
                vec!["main hint #0".to_string(), "other hint #0".to_string()],
                cached_hint_labels(editor),
                "Cache should update for both excerpts despite hints display was disabled"
            );
            assert!(
                visible_hint_labels(editor, cx).is_empty(),
                "All hints are disabled and should not be shown despite being present in the cache"
            );
            assert_eq!(
                editor.inlay_hint_cache().version,
                2,
                "Cache should update once per excerpt query"
            );
        });

        editor.update(cx, |editor, cx| {
            editor.buffer().update(cx, |multibuffer, cx| {
                multibuffer.remove_excerpts(buffer_2_excerpts, cx)
            })
        });
        cx.foreground().run_until_parked();
        editor.update(cx, |editor, cx| {
            assert_eq!(
                vec!["main hint #0".to_string()],
                cached_hint_labels(editor),
                "For the removed excerpt, should clean corresponding cached hints"
            );
            assert!(
                visible_hint_labels(editor, cx).is_empty(),
                "All hints are disabled and should not be shown despite being present in the cache"
            );
            assert_eq!(
                editor.inlay_hint_cache().version,
                3,
                "Excerpt removal should trigger a cache update"
            );
        });

        update_test_language_settings(cx, |settings| {
            settings.defaults.inlay_hints = Some(InlayHintSettings {
                enabled: true,
                show_type_hints: true,
                show_parameter_hints: true,
                show_other_hints: true,
            })
        });
        cx.foreground().run_until_parked();
        editor.update(cx, |editor, cx| {
            let expected_hints = vec!["main hint #0".to_string()];
            assert_eq!(
                expected_hints,
                cached_hint_labels(editor),
                "Hint display settings change should not change the cache"
            );
            assert_eq!(
                expected_hints,
                visible_hint_labels(editor, cx),
                "Settings change should make cached hints visible"
            );
            assert_eq!(
                editor.inlay_hint_cache().version,
                4,
                "Settings change should trigger a cache update"
            );
        });
    }

    #[gpui::test]
    async fn test_inside_char_boundary_range_hints(cx: &mut gpui::TestAppContext) {
        init_test(cx, |settings| {
            settings.defaults.inlay_hints = Some(InlayHintSettings {
                enabled: true,
                show_type_hints: true,
                show_parameter_hints: true,
                show_other_hints: true,
            })
        });

        let mut language = Language::new(
            LanguageConfig {
                name: "Rust".into(),
                path_suffixes: vec!["rs".to_string()],
                ..Default::default()
            },
            Some(tree_sitter_rust::language()),
        );
        let mut fake_servers = language
            .set_fake_lsp_adapter(Arc::new(FakeLspAdapter {
                capabilities: lsp::ServerCapabilities {
                    inlay_hint_provider: Some(lsp::OneOf::Left(true)),
                    ..Default::default()
                },
                ..Default::default()
            }))
            .await;
        let fs = FakeFs::new(cx.background());
        fs.insert_tree(
            "/a",
            json!({
                "main.rs": format!(r#"fn main() {{\n{}\n}}"#, format!("let i = {};\n", "√".repeat(10)).repeat(500)),
                "other.rs": "// Test file",
            }),
        )
        .await;
        let project = Project::test(fs, ["/a".as_ref()], cx).await;
        project.update(cx, |project, _| project.languages().add(Arc::new(language)));
        let workspace = cx
            .add_window(|cx| Workspace::test_new(project.clone(), cx))
            .root(cx);
        let worktree_id = workspace.update(cx, |workspace, cx| {
            workspace.project().read_with(cx, |project, cx| {
                project.worktrees(cx).next().unwrap().read(cx).id()
            })
        });

        let _buffer = project
            .update(cx, |project, cx| {
                project.open_local_buffer("/a/main.rs", cx)
            })
            .await
            .unwrap();
        cx.foreground().run_until_parked();
        cx.foreground().start_waiting();
        let fake_server = fake_servers.next().await.unwrap();
        let editor = workspace
            .update(cx, |workspace, cx| {
                workspace.open_path((worktree_id, "main.rs"), None, true, cx)
            })
            .await
            .unwrap()
            .downcast::<Editor>()
            .unwrap();
        let lsp_request_count = Arc::new(AtomicU32::new(0));
        let closure_lsp_request_count = Arc::clone(&lsp_request_count);
        fake_server
            .handle_request::<lsp::request::InlayHintRequest, _, _>(move |params, _| {
                let task_lsp_request_count = Arc::clone(&closure_lsp_request_count);
                async move {
                    assert_eq!(
                        params.text_document.uri,
                        lsp::Url::from_file_path("/a/main.rs").unwrap(),
                    );
                    let query_start = params.range.start;
                    let i = Arc::clone(&task_lsp_request_count).fetch_add(1, Ordering::Release) + 1;
                    Ok(Some(vec![lsp::InlayHint {
                        position: query_start,
                        label: lsp::InlayHintLabel::String(i.to_string()),
                        kind: None,
                        text_edits: None,
                        tooltip: None,
                        padding_left: None,
                        padding_right: None,
                        data: None,
                    }]))
                }
            })
            .next()
            .await;

        cx.foreground().run_until_parked();
        editor.update(cx, |editor, cx| {
            editor.change_selections(None, cx, |s| {
                s.select_ranges([Point::new(10, 0)..Point::new(10, 0)])
            })
        });
        cx.foreground().run_until_parked();
        editor.update(cx, |editor, cx| {
            let expected_hints = vec!["1".to_string()];
            assert_eq!(expected_hints, cached_hint_labels(editor));
            assert_eq!(expected_hints, visible_hint_labels(editor, cx));
            assert_eq!(editor.inlay_hint_cache().version, 1);
        });
    }

    #[gpui::test]
    async fn test_toggle_inlay_hints(cx: &mut gpui::TestAppContext) {
        init_test(cx, |settings| {
            settings.defaults.inlay_hints = Some(InlayHintSettings {
                enabled: false,
                show_type_hints: true,
                show_parameter_hints: true,
                show_other_hints: true,
            })
        });

        let (file_with_hints, editor, fake_server) = prepare_test_objects(cx).await;

        editor.update(cx, |editor, cx| {
            editor.toggle_inlay_hints(&crate::ToggleInlayHints, cx)
        });
        cx.foreground().start_waiting();
        let lsp_request_count = Arc::new(AtomicU32::new(0));
        let closure_lsp_request_count = Arc::clone(&lsp_request_count);
        fake_server
            .handle_request::<lsp::request::InlayHintRequest, _, _>(move |params, _| {
                let task_lsp_request_count = Arc::clone(&closure_lsp_request_count);
                async move {
                    assert_eq!(
                        params.text_document.uri,
                        lsp::Url::from_file_path(file_with_hints).unwrap(),
                    );

                    let i = Arc::clone(&task_lsp_request_count).fetch_add(1, Ordering::SeqCst) + 1;
                    Ok(Some(vec![lsp::InlayHint {
                        position: lsp::Position::new(0, i),
                        label: lsp::InlayHintLabel::String(i.to_string()),
                        kind: None,
                        text_edits: None,
                        tooltip: None,
                        padding_left: None,
                        padding_right: None,
                        data: None,
                    }]))
                }
            })
            .next()
            .await;
        cx.foreground().run_until_parked();
        editor.update(cx, |editor, cx| {
            let expected_hints = vec!["1".to_string()];
            assert_eq!(
                expected_hints,
                cached_hint_labels(editor),
                "Should display inlays after toggle despite them disabled in settings"
            );
            assert_eq!(expected_hints, visible_hint_labels(editor, cx));
            assert_eq!(
                editor.inlay_hint_cache().version,
                1,
                "First toggle should be cache's first update"
            );
        });

        editor.update(cx, |editor, cx| {
            editor.toggle_inlay_hints(&crate::ToggleInlayHints, cx)
        });
        cx.foreground().run_until_parked();
        editor.update(cx, |editor, cx| {
            assert!(
                cached_hint_labels(editor).is_empty(),
                "Should clear hints after 2nd toggle"
            );
            assert!(visible_hint_labels(editor, cx).is_empty());
            assert_eq!(editor.inlay_hint_cache().version, 2);
        });

        update_test_language_settings(cx, |settings| {
            settings.defaults.inlay_hints = Some(InlayHintSettings {
                enabled: true,
                show_type_hints: true,
                show_parameter_hints: true,
                show_other_hints: true,
            })
        });
        cx.foreground().run_until_parked();
        editor.update(cx, |editor, cx| {
            let expected_hints = vec!["2".to_string()];
            assert_eq!(
                expected_hints,
                cached_hint_labels(editor),
                "Should query LSP hints for the 2nd time after enabling hints in settings"
            );
            assert_eq!(expected_hints, visible_hint_labels(editor, cx));
            assert_eq!(editor.inlay_hint_cache().version, 3);
        });

        editor.update(cx, |editor, cx| {
            editor.toggle_inlay_hints(&crate::ToggleInlayHints, cx)
        });
        cx.foreground().run_until_parked();
        editor.update(cx, |editor, cx| {
            assert!(
                cached_hint_labels(editor).is_empty(),
                "Should clear hints after enabling in settings and a 3rd toggle"
            );
            assert!(visible_hint_labels(editor, cx).is_empty());
            assert_eq!(editor.inlay_hint_cache().version, 4);
        });

        editor.update(cx, |editor, cx| {
            editor.toggle_inlay_hints(&crate::ToggleInlayHints, cx)
        });
        cx.foreground().run_until_parked();
        editor.update(cx, |editor, cx| {
            let expected_hints = vec!["3".to_string()];
            assert_eq!(
                expected_hints,
                cached_hint_labels(editor),
                "Should query LSP hints for the 3rd time after enabling hints in settings and toggling them back on"
            );
            assert_eq!(expected_hints, visible_hint_labels(editor, cx));
            assert_eq!(editor.inlay_hint_cache().version, 5);
        });
    }

    pub(crate) fn init_test(cx: &mut TestAppContext, f: impl Fn(&mut AllLanguageSettingsContent)) {
        cx.foreground().forbid_parking();

        cx.update(|cx| {
            cx.set_global(SettingsStore::test(cx));
            theme::init((), cx);
            client::init_settings(cx);
            language::init(cx);
            Project::init_settings(cx);
            workspace::init_settings(cx);
            crate::init(cx);
        });

        update_test_language_settings(cx, f);
    }

    async fn prepare_test_objects(
        cx: &mut TestAppContext,
    ) -> (&'static str, ViewHandle<Editor>, FakeLanguageServer) {
        let mut language = Language::new(
            LanguageConfig {
                name: "Rust".into(),
                path_suffixes: vec!["rs".to_string()],
                ..Default::default()
            },
            Some(tree_sitter_rust::language()),
        );
        let mut fake_servers = language
            .set_fake_lsp_adapter(Arc::new(FakeLspAdapter {
                capabilities: lsp::ServerCapabilities {
                    inlay_hint_provider: Some(lsp::OneOf::Left(true)),
                    ..Default::default()
                },
                ..Default::default()
            }))
            .await;

        let fs = FakeFs::new(cx.background());
        fs.insert_tree(
            "/a",
            json!({
                "main.rs": "fn main() { a } // and some long comment to ensure inlays are not trimmed out",
                "other.rs": "// Test file",
            }),
        )
        .await;

        let project = Project::test(fs, ["/a".as_ref()], cx).await;
        project.update(cx, |project, _| project.languages().add(Arc::new(language)));
        let workspace = cx
            .add_window(|cx| Workspace::test_new(project.clone(), cx))
            .root(cx);
        let worktree_id = workspace.update(cx, |workspace, cx| {
            workspace.project().read_with(cx, |project, cx| {
                project.worktrees(cx).next().unwrap().read(cx).id()
            })
        });

        let _buffer = project
            .update(cx, |project, cx| {
                project.open_local_buffer("/a/main.rs", cx)
            })
            .await
            .unwrap();
        cx.foreground().run_until_parked();
        cx.foreground().start_waiting();
        let fake_server = fake_servers.next().await.unwrap();
        let editor = workspace
            .update(cx, |workspace, cx| {
                workspace.open_path((worktree_id, "main.rs"), None, true, cx)
            })
            .await
            .unwrap()
            .downcast::<Editor>()
            .unwrap();

        editor.update(cx, |editor, cx| {
            assert!(cached_hint_labels(editor).is_empty());
            assert!(visible_hint_labels(editor, cx).is_empty());
            assert_eq!(editor.inlay_hint_cache().version, 0);
        });

        ("/a/main.rs", editor, fake_server)
    }

    pub fn cached_hint_labels(editor: &Editor) -> Vec<String> {
        let mut labels = Vec::new();
        for (_, excerpt_hints) in &editor.inlay_hint_cache().hints {
            let excerpt_hints = excerpt_hints.read();
            for id in &excerpt_hints.ordered_hints {
                labels.push(excerpt_hints.hints_by_id[id].text());
            }
        }

        labels.sort();
        labels
    }

    pub fn visible_hint_labels(editor: &Editor, cx: &ViewContext<'_, '_, Editor>) -> Vec<String> {
        let mut hints = editor
            .visible_inlay_hints(cx)
            .into_iter()
            .map(|hint| hint.text.to_string())
            .collect::<Vec<_>>();
        hints.sort();
        hints
    }
}