T23c round 2 fix

- a trigger opens only its word, so a path keeps its slashes in the query
- suggestions reveal the cursor once the list has its bounds: Popup takes a
  row to reveal, and a canvas inside the list asks for it and one more frame

TASKS.md

@@ -262,3 +262,4 @@ Per-component lines live in `tasks/`. Tags there:
 | T23b | 2 | FAIL | the gallery's narrow passage built a vec of one range, which clippy refuses, so the checks failed |
 | T23b | 3 | PASS | |
 | T23c | 1 | FAIL | suggestion arrows landed on disabled rows and left the cursor out of view; a dot ended a file mention; the drop veil never showed, since gpui styles a drag-over only on an element with a hitbox; a parameter's places came from its step alone; the gallery's prompt menu and Reset only logged |
+| T23c | 2 | FAIL | a slash inside a path read as a new trigger, closing the file suggestions; a list whose first rows were disabled opened with its cursor out of view |

src/chat/tests/compose.rs

@@ -30,9 +30,13 @@ impl Render for Compose {
         .commands(self.commands.clone(), move |value, _, cx| {
             command.update(cx, |compose, _| compose.picked.push(value.clone()))
         })
-        .context([Choice::new("lift", "lift.rs")], move |value, _, cx| {
-            mention.update(cx, |compose, _| compose.picked.push(value.clone()))
-        })
+        .context(
+            [
+                Choice::new("lift", "lift.rs"),
+                Choice::new("src", "src/lift.rs"),
+            ],
+            move |value, _, cx| mention.update(cx, |compose, _| compose.picked.push(value.clone())),
+        )
         .on_drop(|_, _, _| {});
         let input = if self.busy {
             input.busy(|_, _| {})
@@ -170,14 +174,19 @@ fn a_file_name_keeps_its_suggestions_past_a_dot(cx: &mut TestAppContext) {
 }
 
 #[gpui::test]
-fn arrows_pass_disabled_rows_and_keep_the_cursor_in_view(cx: &mut TestAppContext) {
-    let (compose, cx) = open(false, numbered(&[1]), cx);
-    cx.simulate_input("/");
-    frames(cx);
-    for _ in 0..16 {
-        cx.simulate_keystrokes("down");
-        frames(cx);
-    }
+fn a_path_keeps_its_suggestions_past_a_slash(cx: &mut TestAppContext) {
+    let (compose, cx) = open(false, summarize(), cx);
+    cx.simulate_input("see @src/");
+    settle(cx);
+    cx.simulate_keystrokes("enter");
+    settle(cx);
+    assert_eq!(text(&compose, cx), "see ");
+    assert_eq!(picked(&compose, cx), ["src"]);
+    assert_eq!(compose.read_with(cx, |compose, _| compose.sent), 0);
+}
+
+/// Clicks near the foot of the command list that hangs under the slash.
+fn click_list_foot(compose: &Entity<Compose>, cx: &mut VisualTestContext) {
     let (anchor, height) = cx.update(|window, cx| {
         let anchor = compose.read(cx).field.read(cx).bounds_for(0);
         let height = cx.theme().list_max_height().to_pixels(window.rem_size());
@@ -189,6 +198,32 @@ fn arrows_pass_disabled_rows_and_keep_the_cursor_in_view(cx: &mut TestAppContext
     );
     cx.simulate_mouse_move(foot, None, Modifiers::none());
     cx.simulate_click(foot, Modifiers::none());
+}
+
+#[gpui::test]
+fn the_list_opens_on_its_first_enabled_row_in_view(cx: &mut TestAppContext) {
+    let disabled: Vec<usize> = (0..17).collect();
+    let (compose, cx) = open(false, numbered(&disabled), cx);
+    cx.simulate_input("/");
+    frames(cx);
+    click_list_foot(&compose, cx);
+    assert_eq!(
+        picked(&compose, cx),
+        ["c17"],
+        "the list opens scrolled to its cursor"
+    );
+}
+
+#[gpui::test]
+fn arrows_pass_disabled_rows_and_keep_the_cursor_in_view(cx: &mut TestAppContext) {
+    let (compose, cx) = open(false, numbered(&[1]), cx);
+    cx.simulate_input("/");
+    frames(cx);
+    for _ in 0..16 {
+        cx.simulate_keystrokes("down");
+        frames(cx);
+    }
+    click_list_foot(&compose, cx);
     assert_eq!(
         picked(&compose, cx),
         ["c17"],

src/forms/combobox.rs

@@ -256,6 +256,7 @@ impl RenderOnce for Combobox {
                         pick,
                         dismiss: None,
                         scroll: Some(&scroll),
+                        reveal: None,
                     }
                     .render(window, cx),
                 )

src/forms/masked.rs

@@ -303,6 +303,7 @@ impl RenderOnce for PhoneInput {
                             })
                         })),
                         scroll: None,
+                        reveal: None,
                     }
                     .render(window, cx),
                 )

src/forms/mention.rs

@@ -7,7 +7,7 @@ use gpui::{
 
 use super::{
     Highlight, Input, TextInput,
-    options::{Choice, Pick, Popup, step},
+    options::{Choice, Pick, Popup, Run, step},
     text::{Down, Enter, Up},
 };
 use crate::theme::ActiveTheme;
@@ -19,7 +19,7 @@ pub(crate) fn one_word(ch: char) -> bool {
     ch.is_alphanumeric() || ch == '_'
 }
 
-/// The trigger being typed, its query all `word` characters: its byte offset and char, ending at `caret`.
+/// The trigger that opens the word ending at `caret`, its query all `word` characters: its byte offset and char.
 pub(crate) fn active_trigger(
     text: &str,
     caret: usize,
@@ -27,17 +27,14 @@ pub(crate) fn active_trigger(
     word: fn(char) -> bool,
 ) -> Option<(usize, char)> {
     let before = &text[..caret];
-    let (ix, ch) = before
+    let start = before
         .char_indices()
         .rev()
-        .take_while(|(_, ch)| !ch.is_whitespace())
-        .find(|(_, ch)| triggers.contains(ch))?;
-    let opens = before[..ix]
-        .chars()
-        .next_back()
-        .is_none_or(char::is_whitespace);
-    let query = before[ix + ch.len_utf8()..].chars().all(word);
-    (opens && query).then_some((ix, ch))
+        .find(|(_, ch)| ch.is_whitespace())
+        .map_or(0, |(ix, ch)| ix + ch.len_utf8());
+    let mut chars = before[start..].chars();
+    let trigger = chars.next().filter(|ch| triggers.contains(ch))?;
+    chars.all(word).then_some((start, trigger))
 }
 
 /// Replaces the trigger and its query, `at..caret`, with `text`, as one undo step.
@@ -107,6 +104,7 @@ struct Picking {
     highlighted: usize,
     dismissed: Option<usize>,
     scroll: ScrollHandle,
+    revealed: Option<usize>,
 }
 
 /// The row the cursor rests on: `at` kept in range and off disabled rows.
@@ -118,16 +116,15 @@ fn usable(rows: &[Choice], at: usize) -> usize {
     }
 }
 
-/// Moves the cursor `by` rows past disabled ones and scrolls it into view.
+/// Moves the cursor `by` rows past disabled ones.
 fn move_cursor(picking: &Entity<Picking>, rows: &[Choice], by: isize, cx: &mut App) {
     picking.update(cx, |picking, cx| {
         picking.highlighted = step(rows, picking.highlighted, by);
-        picking.scroll.scroll_to_item(picking.highlighted);
         cx.notify();
     });
 }
 
-/// Rows offered at a trigger in a field's text, and what a pick does: arrows choose past disabled rows, Enter or a press picks, Escape dismisses until the trigger ends.
+/// Rows offered at a trigger in a field's text, and what a pick does: arrows choose past disabled rows, the cursor stays in view, Enter or a press picks, Escape dismisses until the trigger ends.
 pub(crate) struct Suggestions {
     pub id: ElementId,
     pub state: Entity<TextInput>,
@@ -152,10 +149,23 @@ impl Suggestions {
             && !self.rows.is_empty()
             && self.trigger.is_some_and(|ix| dismissed != Some(ix));
         let rows: Rc<[Choice]> = self.rows.into();
+        let shown = open && anchor.is_some();
         let highlighted = usable(&rows, picking.read(cx).highlighted);
-        if highlighted != picking.read(cx).highlighted {
-            picking.update(cx, |picking, _| picking.highlighted = highlighted);
+        let revealed = picking.read(cx).revealed.filter(|_| shown);
+        let stored = (picking.read(cx).highlighted, picking.read(cx).revealed);
+        if (highlighted, revealed) != stored {
+            picking.update(cx, |picking, _| {
+                picking.highlighted = highlighted;
+                picking.revealed = revealed;
+            });
         }
+        let reveal = (shown && revealed != Some(highlighted)).then(|| {
+            let done = picking.clone();
+            let mark: Run = Rc::new(move |_, cx| {
+                done.update(cx, |picking, _| picking.revealed = Some(highlighted))
+            });
+            (highlighted, mark)
+        });
         let scroll = picking.read(cx).scroll.clone();
         log::debug!(
             "suggestions {:?}: open {open}, {} rows, anchor {anchor:?}",
@@ -214,6 +224,7 @@ impl Suggestions {
                         pick: self.pick,
                         dismiss: None,
                         scroll: Some(&scroll),
+                        reveal,
                     }
                     .render(window, cx),
                 )
@@ -333,8 +344,15 @@ mod tests {
         assert_eq!(at("hi @ada lovelace"), None);
         assert_eq!(at("go #rel"), Some((3, '#')));
         assert_eq!(at("see @lift."), None, "a handle is one word");
-        let file = active_trigger("see @lift.rs", 12, &marks, |ch| !ch.is_whitespace());
-        assert_eq!(file, Some((4, '@')), "a file name holds dots");
+        let file =
+            |text: &str| active_trigger(text, text.len(), &['/', '@'], |ch| !ch.is_whitespace());
+        assert_eq!(
+            file("see @lift.rs"),
+            Some((4, '@')),
+            "a file name holds dots"
+        );
+        assert_eq!(file("see @src/"), Some((4, '@')), "a path holds slashes");
+        assert_eq!(file("/usr/bin"), Some((0, '/')));
     }
 
     #[test]

src/forms/multi.rs

@@ -222,6 +222,7 @@ impl RenderOnce for MultiSelect {
                             Picker::show(&close, false, at, cx)
                         })),
                         scroll: Some(&scroll),
+                        reveal: None,
                     }
                     .render(window, cx),
                 )

src/forms/options.rs

@@ -3,7 +3,7 @@ use std::rc::Rc;
 use gpui::{
     Animation, AnimationExt, AnyElement, App, Bounds, Corner, Div, ElementId, InteractiveElement,
     IntoElement, MouseButton, ParentElement, Pixels, ScrollHandle, SharedString, Stateful,
-    StatefulInteractiveElement, Styled, Window, anchored, deferred, div, prelude::*,
+    StatefulInteractiveElement, Styled, Window, anchored, canvas, deferred, div, prelude::*,
 };
 
 use crate::{
@@ -221,6 +221,8 @@ pub(crate) struct Popup<'a> {
     pub pick: Pick,
     pub dismiss: Option<Run>,
     pub scroll: Option<&'a ScrollHandle>,
+    /// A row to scroll into view once the list has its bounds, and what marks it done.
+    pub reveal: Option<(usize, Run)>,
 }
 
 impl Popup<'_> {
@@ -259,7 +261,24 @@ impl Popup<'_> {
             .when_some(self.dismiss, |list, dismiss| {
                 list.on_mouse_down_out(move |_, window, cx| dismiss(window, cx))
             })
-            .children(rows);
+            .children(rows)
+            .when_some(
+                self.scroll.zip(self.reveal),
+                |list, (handle, (ix, done))| {
+                    let handle = handle.clone();
+                    list.child(
+                        canvas(
+                            move |_, window, cx| {
+                                handle.scroll_to_item(ix);
+                                window.request_animation_frame();
+                                done(window, cx);
+                            },
+                            |_, _, _, _| {},
+                        )
+                        .absolute(),
+                    )
+                },
+            );
         float(anchor, self.rows.len(), list, window, cx)
     }
 }

src/forms/search.rs

@@ -113,6 +113,7 @@ impl RenderOnce for SearchInput {
                         pick,
                         dismiss: None,
                         scroll: None,
+                        reveal: None,
                     }
                     .render(window, cx),
                 )

src/forms/select.rs

@@ -224,6 +224,7 @@ pub(crate) fn listing(
                         Picker::show(&close, false, at, cx)
                     })),
                     scroll: Some(&scroll),
+                    reveal: None,
                 }
                 .render(window, cx),
             )