Do not show useless toasts during recursive blaming (#63111)

Follow-up to https://github.com/zed-industries/zed/pull/62614

<img width="1728" height="1084" alt="bad"
src="https://github.com/user-attachments/assets/5fafb9cb-38be-44ba-b8a3-a33dc10106da"
/>

Properly disable actions instead of showing odd toasts and do nothing
when invoked without the prerequisites.

Release Notes:

- N/A

crates/editor/src/element.rs

@@ -511,8 +511,16 @@ impl EditorElement {
         register_action(editor, window, Editor::toggle_git_blame_inline);
         if editor.read(cx).blame().is_some() {
             register_action(editor, window, Editor::open_git_blame_commit);
-            register_action(editor, window, Editor::blame_revision);
-            register_action(editor, window, Editor::blame_previous_revision);
+            if editor.update(cx, |editor, cx| {
+                editor.blame_revision_target(window, cx).is_some()
+            }) {
+                register_action(editor, window, Editor::blame_revision);
+            }
+            if editor.update(cx, |editor, cx| {
+                editor.blame_previous_revision_target(window, cx).is_some()
+            }) {
+                register_action(editor, window, Editor::blame_previous_revision);
+            }
         }
         register_action(editor, window, Editor::toggle_selected_diff_hunks);
         register_action(editor, window, Editor::toggle_staged_selected_diff_hunks);

crates/editor/src/git.rs

@@ -2310,32 +2310,40 @@ impl Editor {
         Some((blame_entry, repository))
     }
 
+    pub(crate) fn blame_revision_target(
+        &mut self,
+        window: &mut Window,
+        cx: &mut Context<Self>,
+    ) -> Option<(RepoPath, Oid, Entity<Repository>)> {
+        let (blame_entry, repository) = self.blame_entry_at_cursor(window, cx)?;
+        let highlighted_sha = self
+            .blame
+            .as_ref()
+            .and_then(|blame| blame.read(cx).highlighted_sha());
+        let (revision, path) = blame_entry.revision_target(highlighted_sha)?;
+        Some((path, revision, repository))
+    }
+
+    pub(crate) fn blame_previous_revision_target(
+        &mut self,
+        window: &mut Window,
+        cx: &mut Context<Self>,
+    ) -> Option<(RepoPath, Oid, Entity<Repository>)> {
+        let (blame_entry, repository) = self.blame_entry_at_cursor(window, cx)?;
+        let (revision, path) = blame_entry.previous_revision_target()?;
+        Some((path, revision, repository))
+    }
+
     pub(super) fn blame_revision(
         &mut self,
         _: &BlameRevision,
         window: &mut Window,
         cx: &mut Context<Self>,
     ) {
-        let Some((blame_entry, repository)) = self.blame_entry_at_cursor(window, cx) else {
-            self.show_blame_revision_toast("No blame entry for this line", cx);
+        let Some((path, revision, repository)) = self.blame_revision_target(window, cx) else {
             return;
         };
-        if blame_entry.sha.is_zero() {
-            self.show_blame_revision_toast("Cannot blame revision: the line is not committed", cx);
-            return;
-        }
-        if self
-            .blame
-            .as_ref()
-            .is_some_and(|blame| blame.read(cx).highlighted_sha() == Some(blame_entry.sha))
-        {
-            self.show_blame_revision_toast("Already blaming at this revision", cx);
-            return;
-        }
-        let Some(path) = RepoPath::new(&blame_entry.filename).log_err() else {
-            return;
-        };
-        self.open_blame_revision(path, blame_entry.sha, repository, window, cx);
+        self.open_blame_revision(path, revision, repository, window, cx);
     }
 
     pub(super) fn blame_previous_revision(
@@ -2344,15 +2352,8 @@ impl Editor {
         window: &mut Window,
         cx: &mut Context<Self>,
     ) {
-        let Some((blame_entry, repository)) = self.blame_entry_at_cursor(window, cx) else {
-            self.show_blame_revision_toast("No blame entry for this line", cx);
-            return;
-        };
-        let Some((revision, filename)) = blame_entry.previous_sha_and_filename() else {
-            self.show_blame_revision_toast("No previous revision for this line", cx);
-            return;
-        };
-        let Some(path) = RepoPath::new(filename).log_err() else {
+        let Some((path, revision, repository)) = self.blame_previous_revision_target(window, cx)
+        else {
             return;
         };
         self.open_blame_revision(path, revision, repository, window, cx);
@@ -2380,21 +2381,6 @@ impl Editor {
         );
     }
 
-    fn show_blame_revision_toast(&self, message: &str, cx: &mut Context<Self>) {
-        struct BlameRevisionToast;
-        if let Some(workspace) = self.workspace() {
-            workspace.update(cx, |workspace, cx| {
-                workspace.show_toast(
-                    Toast::new(
-                        NotificationId::unique::<BlameRevisionToast>(),
-                        message.to_owned(),
-                    ),
-                    cx,
-                );
-            });
-        }
-    }
-
     fn has_blame_entries(&self, cx: &App) -> bool {
         self.blame()
             .is_some_and(|blame| blame.read(cx).has_generated_entries())

crates/git/src/blame.rs

@@ -270,6 +270,18 @@ impl BlameEntry {
         Some((sha.parse().ok()?, filename))
     }
 
+    pub fn revision_target(&self, highlighted_sha: Option<Oid>) -> Option<(Oid, RepoPath)> {
+        if self.sha.is_zero() || Some(self.sha) == highlighted_sha {
+            return None;
+        }
+        Some((self.sha, RepoPath::new(&self.filename).ok()?))
+    }
+
+    pub fn previous_revision_target(&self) -> Option<(Oid, RepoPath)> {
+        let (sha, filename) = self.previous_sha_and_filename()?;
+        Some((sha, RepoPath::new(filename).ok()?))
+    }
+
     pub fn author_offset_date_time(&self) -> Result<time::OffsetDateTime> {
         if let (Some(author_time), Some(author_tz)) = (self.author_time, &self.author_tz) {
             let format = format_description!("[offset_hour][offset_minute]");

crates/git_ui/src/blame_ui.rs

@@ -555,13 +555,8 @@ fn deploy_blame_entry_context_menu(
         .and_then(|blame| blame.read(cx).highlighted_sha());
     let context_menu = ContextMenu::build(window, cx, move |menu, _, _| {
         let sha = format!("{}", blame_entry.sha);
-        let blame_revision = (!blame_entry.sha.is_zero()
-            && Some(blame_entry.sha) != highlighted_sha)
-            .then_some(blame_entry.sha)
-            .zip(RepoPath::new(&blame_entry.filename).ok());
-        let blame_previous_revision = blame_entry
-            .previous_sha_and_filename()
-            .and_then(|(sha, filename)| Some((sha, RepoPath::new(filename).ok()?)));
+        let blame_revision = blame_entry.revision_target(highlighted_sha);
+        let blame_previous_revision = blame_entry.previous_revision_target();
         let has_blame_targets = blame_revision.is_some() || blame_previous_revision.is_some();
         menu.on_blur_subscription(Subscription::new(|| {}))
             .entry("Copy Commit SHA", None, move |_, cx| {