C14.8 r1: the outline scrolls in its pane

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

apps/ely-mark/src/desk.rs

@@ -40,7 +40,7 @@ pub struct Desk {
     pub going: Option<(PathBuf, usize)>,
     /// The path each tab last put in the recent list.
     pub remembered: HashMap<u64, PathBuf>,
-    side: Entity<crate::side::Side>,
+    pub(crate) side: Entity<crate::side::Side>,
     pub watcher: Option<notify::RecommendedWatcher>,
     /// The folders the watcher covers.
     pub watched: Vec<PathBuf>,
@@ -449,4 +449,4 @@ fn large_banner(
 }
 
 #[cfg(test)]
-mod tests;
+pub(crate) mod tests;

apps/ely-mark/src/desk/tests.rs

@@ -7,7 +7,7 @@ use super::{Desk, open_in};
 use crate::view::Mode;
 
 /// ElyMark over a fresh data folder, as `main` opens it.
-fn start(cx: &mut TestAppContext, data: &Path) -> (Entity<Desk>, &'static mut VisualTestContext) {
+pub(crate) fn start(cx: &mut TestAppContext, data: &Path) -> (Entity<Desk>, &'static mut VisualTestContext) {
     // The file watcher runs on a real thread.
     cx.executor().allow_parking();
     cx.update(ely_gpui_component::init_for_tests);
@@ -33,7 +33,7 @@ fn start(cx: &mut TestAppContext, data: &Path) -> (Entity<Desk>, &'static mut Vi
     (desk, cx)
 }
 
-fn open(desk: &Entity<Desk>, path: &Path, cx: &mut VisualTestContext) {
+pub(crate) fn open(desk: &Entity<Desk>, path: &Path, cx: &mut VisualTestContext) {
     desk.update(cx, |desk, cx| desk.open_path(path.to_path_buf(), cx));
     cx.run_until_parked();
 }

apps/ely-mark/src/side.rs

@@ -6,6 +6,7 @@ use ely_gpui_component::{
     buttons::{Button, SegmentedControl},
     feedback::EmptyState,
     forms::{InputEvent, SearchInput, TextInput},
+    layout::ScrollArea,
     lists::{FileTree, ListItem, Outline, SelectableList},
     primitives::IconName,
     theme::ControlSize,
@@ -13,7 +14,8 @@ use ely_gpui_component::{
 use ely_office::prelude::*;
 use ely_ui::{commands, i18n::text};
 use gpui::{
-    AnyElement, AppContext as _, Context, Entity, IntoElement, ParentElement as _, Render,
+    AnyElement, AppContext as _, Context, Entity, InteractiveElement as _, IntoElement,
+    ParentElement as _, Render,
     SharedString, Styled as _, WeakEntity, Window, div,
 };
 
@@ -248,15 +250,18 @@ impl Side {
                 outline.item(at.to_string(), heading.title.clone(), heading.level)
             },
         );
-        outline
-            .on_select(move |key, window, cx| {
+        let outline = outline.on_select(move |key, window, cx| {
                 let Some(heading) = key.parse::<usize>().ok().and_then(|at| headings.get(at)) else {
                     return log::error!("mark: the outline chose no heading");
                 };
                 // The heading in view, the caret on it.
                 let line = heading.line;
                 view.update(cx, |view, cx| view.reveal(line, window, cx));
-            })
+            });
+        ScrollArea::new("mark-outline-scroll")
+            .vertical()
+            .size_full()
+            .child(div().debug_selector(|| "mark-outline".into()).child(outline))
             .into_any_element()
     }
 
@@ -374,3 +379,6 @@ impl Render for Side {
             .into_any_element()
     }
 }
+
+#[cfg(test)]
+mod tests;

apps/ely-mark/src/side/tests.rs

@@ -0,0 +1,47 @@
+use gpui::{ScrollDelta, ScrollWheelEvent, TestAppContext, point, px};
+
+use super::Pane;
+use crate::desk::tests::{open, start};
+
+#[gpui::test]
+fn a_long_outline_scrolls_to_its_last_heading(cx: &mut TestAppContext) {
+    let (data, files) = (
+        tempfile::tempdir().expect("data"),
+        tempfile::tempdir().expect("files"),
+    );
+    let path = files.path().join("long.md");
+    let text: String = (0..100).map(|n| format!("# Heading {n}\n\n")).collect();
+    std::fs::write(&path, text).expect("a file");
+    let (desk, cx) = start(cx, data.path());
+    open(&desk, &path, cx);
+    let side = desk.read_with(cx, |desk, _| desk.side.clone());
+    side.update(cx, |side, cx| {
+        side.pane = Pane::Outline;
+        cx.notify();
+    });
+    cx.run_until_parked();
+    let before = cx
+        .debug_bounds("mark-outline")
+        .expect("the outline is drawn");
+    let window = cx.update(|window, _| window.viewport_size());
+    assert!(
+        before.bottom() > window.height,
+        "the outline is longer than the window"
+    );
+    let at = point(before.left() + px(20.0), px(300.0));
+    for _ in 0..20 {
+        cx.simulate_event(ScrollWheelEvent {
+            position: at,
+            delta: ScrollDelta::Pixels(point(px(0.0), px(-1000.0))),
+            ..Default::default()
+        });
+        cx.run_until_parked();
+    }
+    let after = cx
+        .debug_bounds("mark-outline")
+        .expect("the outline is drawn");
+    assert!(
+        after.bottom() <= window.height,
+        "the last heading is in view: {after:?}"
+    );
+}