Remove worktree and project notifies (#26244)

This reduces the number of multibuffer syncs from 100,000 to 20,000.
Before this change each editor individually observed the project, so
literally any project change was amplified by the number of editors you
had open.

Now editors listen to their buffers instead of the project, and other
users of `cx.observe` on the project have been updated to use specific
events to reduce churn.

Follow up to #26237


Release Notes:

- Improved performance of Zed in large repos with lots of file system
events.

---------

Co-authored-by: Max Brunsfeld <maxbrunsfeld@gmail.com>

crates/worktree/src/worktree.rs

@@ -1570,7 +1570,6 @@ impl LocalWorktree {
                             this.update_abs_path_and_refresh(new_path, cx);
                         }
                     }
-                    cx.notify();
                 })
                 .ok();
             }
@@ -5889,14 +5888,21 @@ impl WorktreeModelHandle for Entity<Worktree> {
                 .await
                 .unwrap();
 
-            cx.condition(&tree, |tree, _| tree.entry_for_path(file_name).is_some())
-                .await;
+            let mut events = cx.events(&tree);
+            while events.next().await.is_some() {
+                if tree.update(cx, |tree, _| tree.entry_for_path(file_name).is_some()) {
+                    break;
+                }
+            }
 
             fs.remove_file(&root_path.join(file_name), Default::default())
                 .await
                 .unwrap();
-            cx.condition(&tree, |tree, _| tree.entry_for_path(file_name).is_none())
-                .await;
+            while events.next().await.is_some() {
+                if tree.update(cx, |tree, _| tree.entry_for_path(file_name).is_none()) {
+                    break;
+                }
+            }
 
             cx.update(|cx| tree.read(cx).as_local().unwrap().scan_complete())
                 .await;
@@ -5950,19 +5956,22 @@ impl WorktreeModelHandle for Entity<Worktree> {
                 .await
                 .unwrap();
 
-            cx.condition(&tree, |tree, _| {
-                scan_id_increased(tree, &mut git_dir_scan_id)
-            })
-            .await;
+            let mut events = cx.events(&tree);
+            while events.next().await.is_some() {
+                if tree.update(cx, |tree, _| scan_id_increased(tree, &mut git_dir_scan_id)) {
+                    break;
+                }
+            }
 
             fs.remove_file(&root_path.join(file_name), Default::default())
                 .await
                 .unwrap();
 
-            cx.condition(&tree, |tree, _| {
-                scan_id_increased(tree, &mut git_dir_scan_id)
-            })
-            .await;
+            while events.next().await.is_some() {
+                if tree.update(cx, |tree, _| scan_id_increased(tree, &mut git_dir_scan_id)) {
+                    break;
+                }
+            }
 
             cx.update(|cx| tree.read(cx).as_local().unwrap().scan_complete())
                 .await;

crates/worktree/src/worktree_tests.rs

@@ -12,6 +12,7 @@ use git::{
     },
     GITIGNORE,
 };
+use git2::RepositoryInitOptions;
 use gpui::{AppContext as _, BorrowAppContext, Context, Task, TestAppContext};
 use parking_lot::Mutex;
 use postage::stream::Stream;
@@ -855,7 +856,7 @@ async fn test_write_file(cx: &mut TestAppContext) {
         "ignored-dir": {}
     }));
 
-    let tree = Worktree::local(
+    let worktree = Worktree::local(
         dir.path(),
         true,
         Arc::new(RealFs::default()),
@@ -868,32 +869,34 @@ async fn test_write_file(cx: &mut TestAppContext) {
     #[cfg(not(target_os = "macos"))]
     fs::fs_watcher::global(|_| {}).unwrap();
 
-    cx.read(|cx| tree.read(cx).as_local().unwrap().scan_complete())
+    cx.read(|cx| worktree.read(cx).as_local().unwrap().scan_complete())
         .await;
-    tree.flush_fs_events(cx).await;
+    worktree.flush_fs_events(cx).await;
 
-    tree.update(cx, |tree, cx| {
-        tree.write_file(
-            Path::new("tracked-dir/file.txt"),
-            "hello".into(),
-            Default::default(),
-            cx,
-        )
-    })
-    .await
-    .unwrap();
-    tree.update(cx, |tree, cx| {
-        tree.write_file(
-            Path::new("ignored-dir/file.txt"),
-            "world".into(),
-            Default::default(),
-            cx,
-        )
-    })
-    .await
-    .unwrap();
+    worktree
+        .update(cx, |tree, cx| {
+            tree.write_file(
+                Path::new("tracked-dir/file.txt"),
+                "hello".into(),
+                Default::default(),
+                cx,
+            )
+        })
+        .await
+        .unwrap();
+    worktree
+        .update(cx, |tree, cx| {
+            tree.write_file(
+                Path::new("ignored-dir/file.txt"),
+                "world".into(),
+                Default::default(),
+                cx,
+            )
+        })
+        .await
+        .unwrap();
 
-    tree.read_with(cx, |tree, _| {
+    worktree.read_with(cx, |tree, _| {
         let tracked = tree.entry_for_path("tracked-dir/file.txt").unwrap();
         let ignored = tree.entry_for_path("ignored-dir/file.txt").unwrap();
         assert!(!tracked.is_ignored);
@@ -3349,7 +3352,7 @@ async fn test_conflicted_cherry_pick(cx: &mut TestAppContext) {
         .expect("Failed to get HEAD")
         .peel_to_commit()
         .expect("HEAD is not a commit");
-    git_checkout("refs/heads/master", &repo);
+    git_checkout("refs/heads/main", &repo);
     std::fs::write(root_path.join("project/a.txt"), "b").unwrap();
     git_add("a.txt", &repo);
     git_commit("improve letter", &repo);
@@ -3479,7 +3482,9 @@ const MODIFIED: GitSummary = GitSummary {
 
 #[track_caller]
 fn git_init(path: &Path) -> git2::Repository {
-    git2::Repository::init(path).expect("Failed to initialize git repository")
+    let mut init_opts = RepositoryInitOptions::new();
+    init_opts.initial_head("main");
+    git2::Repository::init_opts(path, &init_opts).expect("Failed to initialize git repository")
 }
 
 #[track_caller]