Optimize file finder subscriptions (#8343)

Fixes #7519 

Optimizes file finder subscriptions — it now only subscribes to
worktrees updates instead of all project updates.

Project panel could also be optimized this way, I guess.

Release Notes:

- Fix selection resets in the file finder during language server
startup ([7519](https://github.com/zed-industries/zed/issues/7519))

crates/file_finder/src/file_finder.rs

@@ -365,14 +365,7 @@ impl FileFinderDelegate {
         history_items: Vec<FoundPath>,
         cx: &mut ViewContext<FileFinder>,
     ) -> Self {
-        cx.observe(&project, |file_finder, _, cx| {
-            //todo We should probably not re-render on every project anything
-            file_finder
-                .picker
-                .update(cx, |picker, cx| picker.refresh(cx))
-        })
-        .detach();
-
+        Self::subscribe_to_updates(&project, cx);
         Self {
             file_finder,
             workspace,
@@ -389,6 +382,20 @@ impl FileFinderDelegate {
         }
     }
 
+    fn subscribe_to_updates(project: &Model<Project>, cx: &mut ViewContext<FileFinder>) {
+        cx.subscribe(project, |file_finder, _, event, cx| {
+            match event {
+                project::Event::WorktreeUpdatedEntries(_, _)
+                | project::Event::WorktreeAdded
+                | project::Event::WorktreeRemoved(_) => file_finder
+                    .picker
+                    .update(cx, |picker, cx| picker.refresh(cx)),
+                _ => {}
+            };
+        })
+        .detach();
+    }
+
     fn spawn_search(
         &mut self,
         query: PathLikeWithPosition<FileSearchQuery>,

crates/file_finder/src/file_finder_tests.rs

@@ -1,9 +1,10 @@
-use std::{assert_eq, path::Path, time::Duration};
+use std::{assert_eq, future::IntoFuture, path::Path, time::Duration};
 
 use super::*;
 use editor::Editor;
 use gpui::{Entity, TestAppContext, VisualTestContext};
 use menu::{Confirm, SelectNext};
+use project::worktree::FS_WATCH_LATENCY;
 use serde_json::json;
 use workspace::{AppState, Workspace};
 
@@ -1337,6 +1338,137 @@ async fn test_nonexistent_history_items_not_shown(cx: &mut gpui::TestAppContext)
         });
 }
 
+#[gpui::test]
+async fn test_search_results_refreshed_on_worktree_updates(cx: &mut gpui::TestAppContext) {
+    let app_state = init_test(cx);
+
+    app_state
+        .fs
+        .as_fake()
+        .insert_tree(
+            "/src",
+            json!({
+                "lib.rs": "// Lib file",
+                "main.rs": "// Bar file",
+                "read.me": "// Readme file",
+            }),
+        )
+        .await;
+
+    let project = Project::test(app_state.fs.clone(), ["/src".as_ref()], cx).await;
+    let (workspace, cx) = cx.add_window_view(|cx| Workspace::test_new(project.clone(), cx));
+
+    // Initial state
+    let picker = open_file_picker(&workspace, cx);
+    cx.simulate_input("rs");
+    picker.update(cx, |finder, _| {
+        assert_eq!(finder.delegate.matches.len(), 2);
+        assert_match_at_position(finder, 0, "lib.rs");
+        assert_match_at_position(finder, 1, "main.rs");
+    });
+
+    // Delete main.rs
+    app_state
+        .fs
+        .remove_file("/src/main.rs".as_ref(), Default::default())
+        .await
+        .expect("unable to remove file");
+    cx.executor().advance_clock(FS_WATCH_LATENCY);
+
+    // main.rs is in not among search results anymore
+    picker.update(cx, |finder, _| {
+        assert_eq!(finder.delegate.matches.len(), 1);
+        assert_match_at_position(finder, 0, "lib.rs");
+    });
+
+    // Create util.rs
+    app_state
+        .fs
+        .create_file("/src/util.rs".as_ref(), Default::default())
+        .await
+        .expect("unable to create file");
+    cx.executor().advance_clock(FS_WATCH_LATENCY);
+
+    // util.rs is among search results
+    picker.update(cx, |finder, _| {
+        assert_eq!(finder.delegate.matches.len(), 2);
+        assert_match_at_position(finder, 0, "lib.rs");
+        assert_match_at_position(finder, 1, "util.rs");
+    });
+}
+
+#[gpui::test]
+async fn test_search_results_refreshed_on_adding_and_removing_worktrees(
+    cx: &mut gpui::TestAppContext,
+) {
+    let app_state = init_test(cx);
+
+    app_state
+        .fs
+        .as_fake()
+        .insert_tree(
+            "/test",
+            json!({
+                "project_1": {
+                    "bar.rs": "// Bar file",
+                    "lib.rs": "// Lib file",
+                },
+                "project_2": {
+                    "Cargo.toml": "// Cargo file",
+                    "main.rs": "// Main file",
+                }
+            }),
+        )
+        .await;
+
+    let project = Project::test(app_state.fs.clone(), ["/test/project_1".as_ref()], cx).await;
+    let (workspace, cx) = cx.add_window_view(|cx| Workspace::test_new(project.clone(), cx));
+    let worktree_1_id = project.update(cx, |project, cx| {
+        let worktree = project.worktrees().last().expect("worktree not found");
+        worktree.read(cx).id()
+    });
+
+    // Initial state
+    let picker = open_file_picker(&workspace, cx);
+    cx.simulate_input("rs");
+    picker.update(cx, |finder, _| {
+        assert_eq!(finder.delegate.matches.len(), 2);
+        assert_match_at_position(finder, 0, "bar.rs");
+        assert_match_at_position(finder, 1, "lib.rs");
+    });
+
+    // Add new worktree
+    project
+        .update(cx, |project, cx| {
+            project
+                .find_or_create_local_worktree("/test/project_2", true, cx)
+                .into_future()
+        })
+        .await
+        .expect("unable to create workdir");
+    cx.executor().advance_clock(FS_WATCH_LATENCY);
+
+    // main.rs is among search results
+    picker.update(cx, |finder, _| {
+        assert_eq!(finder.delegate.matches.len(), 3);
+        assert_match_at_position(finder, 0, "bar.rs");
+        assert_match_at_position(finder, 1, "lib.rs");
+        assert_match_at_position(finder, 2, "main.rs");
+    });
+
+    // Remove the first worktree
+    project.update(cx, |project, cx| {
+        project.remove_worktree(worktree_1_id, cx);
+    });
+    cx.executor().advance_clock(FS_WATCH_LATENCY);
+
+    // Files from the first worktree are not in the search results anymore
+    picker.update(cx, |finder, _| {
+        assert_eq!(finder.delegate.matches.len(), 1);
+        assert_match_at_position(finder, 0, "main.rs");
+    });
+}
+
 async fn open_close_queried_buffer(
     input: &str,
     expected_matches: usize,

crates/project_core/src/worktree.rs

@@ -68,6 +68,11 @@ use util::{
     ResultExt,
 };
 
+#[cfg(feature = "test-support")]
+pub const FS_WATCH_LATENCY: Duration = Duration::from_millis(100);
+#[cfg(not(feature = "test-support"))]
+const FS_WATCH_LATENCY: Duration = Duration::from_millis(100);
+
 #[derive(Copy, Clone, PartialEq, Eq, Debug, Hash, PartialOrd, Ord)]
 pub struct WorktreeId(usize);
 
@@ -652,7 +657,7 @@ fn start_background_scan_tasks(
         let abs_path = abs_path.to_path_buf();
         let background = cx.background_executor().clone();
         async move {
-            let events = fs.watch(&abs_path, Duration::from_millis(100)).await;
+            let events = fs.watch(&abs_path, FS_WATCH_LATENCY).await;
             let case_sensitive = fs.is_case_sensitive().await.unwrap_or_else(|e| {
                 log::error!(
                     "Failed to determine whether filesystem is case sensitive (falling back to true) due to error: {e:#}"
@@ -4340,7 +4345,7 @@ impl BackgroundScanner {
             return self.executor.simulate_random_delay().await;
         }
 
-        smol::Timer::after(Duration::from_millis(100)).await;
+        smol::Timer::after(FS_WATCH_LATENCY).await;
     }
 }