Fix the project diff sometimes missing updates (#40662)

This PR does two related things:

- First, it gets rid of the undifferentiated `RepositoryEvent::Updated`
in favor of three new events that have clearer definitions:
`BranchChanged`, `StashEntriesChanged`, and `StatusesChanged`. An
implication of this is that we no longer emit a `RepositoryEvent` unless
some git state changed; previously we would emit `RepositoryUpdated`
after doing a git status scan even if no statuses changed.
- Second, it changes the subscription strategy of the project diff to
make it update more robustly. Previously, the project diff only
subscribed to the `GitStore`, so it relied on getting a `GitStoreEvent`
when some buffer's diff hunks changed, even if the git status of the
buffer's file didn't change (e.g. a second hunk in a file that was
already modified). After this PR, it also subscribes to the individual
`BufferDiff` entities for buffers that have a git status, so the
`GitStore` is freed from that responsibility. This also fixes some real
cases where the previous strategy was not effective in keeping the
project diff up to date (captured in a test).

Release Notes:

- Fixed some cases where the project diff would fail to update in
response to git events.

crates/editor/src/editor.rs

@@ -156,7 +156,7 @@ use project::{
         },
         session::{Session, SessionEvent},
     },
-    git_store::{GitStoreEvent, RepositoryEvent},
+    git_store::GitStoreEvent,
     lsp_store::{
         CacheInlayHints, CompletionDocumentation, FormatTrigger, LspFormatTarget,
         OpenLspBufferHandle,
@@ -1978,14 +1978,7 @@ impl Editor {
             let git_store = project.read(cx).git_store().clone();
             let project = project.clone();
             project_subscriptions.push(cx.subscribe(&git_store, move |this, _, event, cx| {
-                if let GitStoreEvent::RepositoryUpdated(
-                    _,
-                    RepositoryEvent::Updated {
-                        new_instance: true, ..
-                    },
-                    _,
-                ) = event
-                {
+                if let GitStoreEvent::RepositoryAdded = event {
                     this.load_diff_task = Some(
                         update_uncommitted_diff_for_buffer(
                             cx.entity(),

crates/editor/src/editor_tests.rs

@@ -12615,18 +12615,6 @@ async fn test_strip_whitespace_and_format_via_lsp(cx: &mut TestAppContext) {
     )
     .await;
 
-    cx.run_until_parked();
-    // Set up a buffer white some trailing whitespace and no trailing newline.
-    cx.set_state(
-        &[
-            "one ",   //
-            "twoˇ",   //
-            "three ", //
-            "four",   //
-        ]
-        .join("\n"),
-    );
-
     // Record which buffer changes have been sent to the language server
     let buffer_changes = Arc::new(Mutex::new(Vec::new()));
     cx.lsp
@@ -12641,8 +12629,6 @@ async fn test_strip_whitespace_and_format_via_lsp(cx: &mut TestAppContext) {
                 );
             }
         });
-    cx.run_until_parked();
-
     // Handle formatting requests to the language server.
     cx.lsp
         .set_request_handler::<lsp::request::Formatting, _, _>({
@@ -12691,6 +12677,18 @@ async fn test_strip_whitespace_and_format_via_lsp(cx: &mut TestAppContext) {
             }
         });
 
+    // Set up a buffer white some trailing whitespace and no trailing newline.
+    cx.set_state(
+        &[
+            "one ",   //
+            "twoˇ",   //
+            "three ", //
+            "four",   //
+        ]
+        .join("\n"),
+    );
+    cx.run_until_parked();
+
     // Submit a format request.
     let format = cx
         .update_editor(|editor, window, cx| editor.format(&Format, window, cx))

crates/editor/src/git/blame.rs

@@ -16,7 +16,7 @@ use markdown::Markdown;
 use multi_buffer::{MultiBuffer, RowInfo};
 use project::{
     Project, ProjectItem as _,
-    git_store::{GitStoreEvent, Repository, RepositoryEvent},
+    git_store::{GitStoreEvent, Repository},
 };
 use smallvec::SmallVec;
 use std::{sync::Arc, time::Duration};
@@ -235,8 +235,8 @@ impl GitBlame {
         let git_store = project.read(cx).git_store().clone();
         let git_store_subscription =
             cx.subscribe(&git_store, move |this, _, event, cx| match event {
-                GitStoreEvent::RepositoryUpdated(_, RepositoryEvent::Updated { .. }, _)
-                | GitStoreEvent::RepositoryAdded(_)
+                GitStoreEvent::RepositoryUpdated(_, _, _)
+                | GitStoreEvent::RepositoryAdded
                 | GitStoreEvent::RepositoryRemoved(_) => {
                     log::debug!("Status of git repositories updated. Regenerating blame data...",);
                     this.generate(cx);