fix: show revision-aware blame in diff buffers

Diff and snapshot sources were excluded before scheduling, and the separate diff renderer never painted attribution. Capture per-side Git provenance, preserve private object stores for historical tabs, and reuse the current-line worker and cache.

src/editor.rs

@@ -1952,6 +1952,7 @@ struct Buffer {
     resolver_readonly: bool,
     snapshot_document_path: Option<PathBuf>,
     snapshot_root: Option<PathBuf>,
+    snapshot_blame: Option<Arc<crate::blame::RevisionSource>>,
     lines: Vec<String>,
     saved_lines: Vec<String>,
     // Invalidate whenever text or the saved baseline changes, including temporary swaps.
@@ -2012,6 +2013,7 @@ impl Buffer {
             resolver_readonly: false,
             snapshot_document_path: None,
             snapshot_root: None,
+            snapshot_blame: None,
             saved_lines: lines.clone(),
             dirty_cache: Cell::new(Some(false)),
             disk_stamp,
@@ -2175,6 +2177,7 @@ pub(crate) struct BlameSource {
     buffer: usize,
     revision: u64,
     pub(crate) path: Arc<Path>,
+    pub(crate) snapshot: Option<Arc<crate::blame::RevisionSource>>,
     pub(crate) row: usize,
     save_revision: u64,
     disk_stamp: Option<FileStamp>,
@@ -5116,6 +5119,14 @@ impl Editor {
         };
         let source = comparison.root.join(relative);
         let root = comparison.root.clone();
+        let blame = comparison.blame[side].as_ref().map(|baseline| {
+            Arc::new(crate::blame::RevisionSource {
+                store: baseline.store.clone(),
+                commit: baseline.commit.clone(),
+                keepalive: baseline.keepalive.clone(),
+                path: relative.clone(),
+            })
+        });
         let lines = diff.snapshot_lines_at(file_index, focus);
         let key = (
             diff.comparison_id.expect("snapshot comparison"),
@@ -5155,6 +5166,7 @@ impl Editor {
         buffer.path = Some(source);
         buffer.snapshot_document_path = Some(document_path);
         buffer.snapshot_root = Some(root);
+        buffer.snapshot_blame = blame;
         buffer.lines = lines;
         buffer.dirty_cache.set(None);
         buffer
@@ -7156,8 +7168,7 @@ impl Editor {
     pub(crate) fn blame_source(&self) -> Option<BlameSource> {
         if !self.git_blame
             || self.should_quit()
-            || self.diff.is_some()
-            || self.active.diff_snapshot.is_some()
+            || (self.active.diff_snapshot.is_some() && self.active.snapshot_blame.is_none())
             || self.active.reload_error.is_some()
         {
             return None;
@@ -7166,6 +7177,7 @@ impl Editor {
             buffer: self.buffer_id(),
             revision: self.text_revision(),
             path: Arc::from(self.path()?),
+            snapshot: self.active.snapshot_blame.clone(),
             row: self.cursor().row,
             save_revision: self.active.save_revision,
             disk_stamp: self.active.disk_stamp,
@@ -7177,13 +7189,12 @@ impl Editor {
     pub(crate) fn blame_file_source_is_current(&self, source: &BlameSource) -> bool {
         self.git_blame
             && !self.should_quit()
-            && self.diff.is_none()
-            && self.active.diff_snapshot.is_none()
             && self.active.reload_error.is_none()
             && source.buffer == self.buffer_id()
             && source.revision == self.text_revision()
             && source.save_revision == self.active.save_revision
             && source.disk_stamp == self.active.disk_stamp
+            && source.snapshot == self.active.snapshot_blame
             && Some(source.path.as_ref()) == self.path()
     }