Files: recent and found files keep the cursor on the file, not its place

RecentFiles and FileSearch keyed their rows by place in the list, so when
an open moved a file to the top, the cursor stayed at the place and the
next Enter opened another file. Rows are keyed by the file's folder and
name, asserted once a list, so the cursor follows the file. A dotfile's
kind reads by its extension, as its icon does.

TASKS.md

@@ -325,3 +325,4 @@ Per-component lines live in `tasks/`. Tags there:
 | T27a | 2 | PASS | |
 | T27b | 1 | FAIL | the listing's fixed columns left no room for names at 280px; a column keyed by its depth handed its cursor to the next folder there |
 | T27b | 2 | PASS | |
+| T27c | 1 | FAIL | recent and found files were keyed by their place, so the cursor left a file an open moved |

src/files/preview.rs

@@ -30,7 +30,7 @@ pub(crate) fn kind(entry: &DirEntry) -> String {
         return "Folder".into();
     }
     match entry.name().rsplit_once('.') {
-        Some((stem, extension)) if !stem.is_empty() => extension.to_uppercase(),
+        Some((_, extension)) if !extension.is_empty() => extension.to_uppercase(),
         _ => "File".into(),
     }
 }

src/files/recent.rs

@@ -23,6 +23,13 @@ pub struct RecentFile {
     pub opened: Timestamp,
 }
 
+impl RecentFile {
+    /// Where it lives: its folder and name.
+    fn place(&self) -> SharedString {
+        format!("{}/{}", self.folder, self.name).into()
+    }
+}
+
 /// The header over a day's files: Today, Yesterday, or the weekday and date.
 pub(crate) fn day_label(day: Date, today: Date) -> String {
     if day == today {
@@ -45,9 +52,17 @@ pub struct RecentFiles {
 
 impl RecentFiles {
     pub fn new(id: impl Into<ElementId>, files: impl IntoIterator<Item = RecentFile>) -> Self {
+        let files: Vec<RecentFile> = files.into_iter().collect();
+        for (ix, file) in files.iter().enumerate() {
+            let place = file.place();
+            assert!(
+                !files[..ix].iter().any(|other| other.place() == place),
+                "{place} twice"
+            );
+        }
         Self {
             id: id.into(),
-            files: files.into_iter().collect(),
+            files,
             zone: None,
             on_open: None,
         }
@@ -96,7 +111,7 @@ impl RenderOnce for RecentFiles {
                             .leading(FileIcon::file(&file.name))
                             .description(file.folder.clone())
                             .trailing(time);
-                    list.row(SharedString::from(ix.to_string()), row)
+                    list.row(file.place(), row)
                 },
             );
             let (id, files, on_open) = (self.id.clone(), files.clone(), self.on_open.clone());
@@ -113,7 +128,10 @@ impl RenderOnce for RecentFiles {
                         .child(day_label(day, today)),
                 )
                 .child(list.on_activate(move |key, window, cx| {
-                    let file = &files[key.parse::<usize>().expect("a row's place")];
+                    let file = files
+                        .iter()
+                        .find(|file| file.place() == *key)
+                        .expect("a listed file");
                     log::info!("recent files {id:?}: open {}", file.name);
                     if let Some(on_open) = &on_open {
                         on_open(file, window, cx);

src/files/search.rs

@@ -21,6 +21,13 @@ pub struct FoundFile {
     pub folder: SharedString,
 }
 
+impl FoundFile {
+    /// Where it lives: its folder and name.
+    fn place(&self) -> SharedString {
+        format!("{}/{}", self.folder, self.name).into()
+    }
+}
+
 /// A search over files: a field the host owns, and what it found, each file with its folder and a count above. The host searches as the text changes; Enter or a double press opens a file.
 #[derive(IntoElement)]
 pub struct FileSearch {
@@ -36,10 +43,18 @@ impl FileSearch {
         query: &Entity<TextInput>,
         found: impl IntoIterator<Item = FoundFile>,
     ) -> Self {
+        let found: Vec<FoundFile> = found.into_iter().collect();
+        for (ix, file) in found.iter().enumerate() {
+            let place = file.place();
+            assert!(
+                !found[..ix].iter().any(|other| other.place() == place),
+                "{place} twice"
+            );
+        }
         Self {
             id: id.into(),
             query: query.clone(),
-            found: found.into_iter().collect(),
+            found,
             on_open: None,
         }
     }
@@ -79,7 +94,7 @@ impl RenderOnce for FileSearch {
                         )
                         .leading(FileIcon::file(&file.name))
                         .description(file.folder.clone());
-                        list.row(SharedString::from(ix.to_string()), row)
+                        list.row(file.place(), row)
                     },
                 );
                 let (id, shown, on_open) = (self.id.clone(), found.clone(), self.on_open);
@@ -93,7 +108,10 @@ impl RenderOnce for FileSearch {
                     .gap_1()
                     .child(quiet(count))
                     .child(list.on_activate(move |key, window, cx| {
-                        let file = &shown[key.parse::<usize>().expect("a row's place")];
+                        let file = shown
+                            .iter()
+                            .find(|file| file.place() == *key)
+                            .expect("a listed file");
                         log::info!("file search {id:?}: open {}", file.name);
                         if let Some(on_open) = &on_open {
                             on_open(file, window, cx);

src/files/tests/find.rs

@@ -30,7 +30,11 @@ fn tab_to(nth: usize, cx: &mut VisualTestContext) {
 fn a_kind_reads_from_the_extension() {
     assert_eq!(kind(&DirEntry::file("Brief.md", 1, then())), "MD");
     assert_eq!(kind(&DirEntry::file("Makefile", 1, then())), "File");
-    assert_eq!(kind(&DirEntry::file(".env", 1, then())), "File");
+    assert_eq!(
+        kind(&DirEntry::file(".env", 1, then())),
+        "ENV",
+        "as the icon map reads it"
+    );
     assert_eq!(kind(&DirEntry::folder("Design", then())), "Folder");
 }
 
@@ -309,3 +313,82 @@ fn an_archive_lists_a_path_once() {
     };
     let _ = ArchiveViewer::new("archive", "a.zip", [entry.clone(), entry]);
 }
+
+/// Three files opened today; an open moves a file to the top, as a host records it.
+struct Reopening {
+    files: Vec<RecentFile>,
+    opened: Vec<SharedString>,
+}
+
+impl Render for Reopening {
+    fn render(&mut self, _: &mut Window, cx: &mut Context<Self>) -> impl IntoElement {
+        let owner = cx.entity();
+        div().w(px(320.0)).child(
+            RecentFiles::new("recent", self.files.clone())
+                .zone(TimeZone::UTC)
+                .on_open(move |file, _, cx| {
+                    owner.update(cx, |host, cx| {
+                        host.opened.push(file.name.clone());
+                        let now = Timestamp::now();
+                        for kept in &mut host.files {
+                            if kept.name == file.name {
+                                kept.opened = now;
+                            }
+                        }
+                        cx.notify();
+                    })
+                }),
+        )
+    }
+}
+
+#[gpui::test]
+fn the_cursor_stays_on_a_file_an_open_moves(cx: &mut TestAppContext) {
+    setup(cx);
+    let midnight = Timestamp::now()
+        .to_zoned(TimeZone::UTC)
+        .start_of_day()
+        .expect("a day starts")
+        .timestamp();
+    let file = |name: &str, minutes: i64| RecentFile {
+        name: SharedString::from(name.to_string()),
+        folder: "Home".into(),
+        opened: midnight + SignedDuration::from_mins(minutes),
+    };
+    let files = vec![file("a.md", 3), file("b.md", 2), file("c.md", 1)];
+    let (host, cx) = cx.add_window_view(move |_, _| Reopening {
+        files,
+        opened: Vec::new(),
+    });
+    cx.update(|window, _| window.activate_window());
+    settle(cx);
+    tab_to(1, cx);
+    press("down", cx);
+    press("enter", cx);
+    press("enter", cx);
+    assert_eq!(
+        host.read_with(cx, |host, _| host.opened.clone()),
+        ["b.md", "b.md"]
+    );
+}
+
+#[test]
+#[should_panic(expected = "Home/a.md twice")]
+fn a_recent_file_is_listed_once() {
+    let file = RecentFile {
+        name: "a.md".into(),
+        folder: "Home".into(),
+        opened: then(),
+    };
+    let _ = RecentFiles::new("recent", [file.clone(), file]);
+}
+
+#[gpui::test]
+#[should_panic(expected = "Home/a.md twice")]
+fn a_found_file_is_listed_once(cx: &mut TestAppContext) {
+    let file = FoundFile {
+        name: "a.md".into(),
+        folder: "Home".into(),
+    };
+    let _ = seeking("a", vec![file.clone(), file], cx);
+}