From a8cdf1d8692b74faba928f8948960277460eade9 Mon Sep 17 00:00:00 2001
From: Cole Miller <cole@zed.dev>
Date: Mon, 25 May 2026 10:42:01 -0400
Subject: [PATCH] Batch excerpt insertions per file when opening commit view
 (#57330)

When viewing the diff for a commit where one of the files has a large
number (hundreds or thousands) of diff hunks, we can get a hang on the
main thread, since there's a large amount of work to recompute diff
transforms for thousands of excerpts. This PR makes it so that we batch
the addition of excerpts, with yield points in between batches so the UI
remains responsive.

We should have something similar for the project diff, but that's a bit
trickier; will address it in a separate PR.

Self-Review Checklist:

- [x] I've reviewed my own diff for quality, security, and reliability
- [x] Unsafe blocks (if any) have justifying comments
- [x] The content is consistent with the [UI/UX
checklist](https://github.com/zed-industries/zed/blob/main/CONTRIBUTING.md#uiux-checklist)
- [ ] Tests cover the new/changed behavior
- [x] Performance impact has been considered and is acceptable

Release Notes:

- Improved performance when opening the commit view with files that have
many diff hunks.
---
 crates/git_ui/src/commit_view.rs | 79 ++++++++++++++++++++------------
 1 file changed, 50 insertions(+), 29 deletions(-)

diff --git a/crates/git_ui/src/commit_view.rs b/crates/git_ui/src/commit_view.rs
index 0109fb0ac57..c6e1ae6ea73 100644
--- a/crates/git_ui/src/commit_view.rs
+++ b/crates/git_ui/src/commit_view.rs
@@ -3,6 +3,7 @@ use buffer_diff::BufferDiff;
 use collections::HashMap;
 use editor::display_map::{BlockPlacement, BlockProperties, BlockStyle};
 use editor::{Addon, Editor, EditorEvent, ExcerptRange, MultiBuffer, multibuffer_context_lines};
+use futures_lite::future::yield_now;
 use git::repository::{CommitDetails, CommitDiff, RepoPath, is_binary_content};
 use git::status::{FileStatus, StatusCode, TrackedStatus};
 use git::{
@@ -392,38 +393,58 @@ impl CommitView {
                     Some(build_buffer_diff(old_text, &buffer, &language_registry, cx).await?)
                 };
 
-                this.update(cx, |this, cx| {
-                    this.multibuffer.update(cx, |multibuffer, cx| {
-                        let snapshot = buffer.read(cx).snapshot();
-                        let path = snapshot.file().unwrap().path().clone();
-                        let excerpt_ranges = if is_binary {
+                let (excerpt_ranges, path) = cx.update(|cx| {
+                    let snapshot = buffer.read(cx).snapshot();
+                    let path = PathKey::with_sort_prefix(
+                        FILE_NAMESPACE_SORT_PREFIX,
+                        snapshot.file().unwrap().path().clone(),
+                    );
+                    let ranges = if is_binary {
+                        vec![language::Point::zero()..snapshot.max_point()]
+                    } else if let Some(buffer_diff) = &buffer_diff {
+                        let diff_snapshot = buffer_diff.read(cx).snapshot(cx);
+                        let mut hunks = diff_snapshot.hunks(&snapshot).peekable();
+                        if hunks.peek().is_none() {
                             vec![language::Point::zero()..snapshot.max_point()]
-                        } else if let Some(buffer_diff) = &buffer_diff {
-                            let diff_snapshot = buffer_diff.read(cx).snapshot(cx);
-                            let mut hunks = diff_snapshot.hunks(&snapshot).peekable();
-                            if hunks.peek().is_none() {
-                                vec![language::Point::zero()..snapshot.max_point()]
-                            } else {
-                                hunks
-                                    .map(|hunk| hunk.buffer_range.to_point(&snapshot))
-                                    .collect::<Vec<_>>()
-                            }
                         } else {
-                            vec![language::Point::zero()..snapshot.max_point()]
-                        };
-
-                        let _is_newly_added = multibuffer.set_excerpts_for_path(
-                            PathKey::with_sort_prefix(FILE_NAMESPACE_SORT_PREFIX, path),
-                            buffer,
-                            excerpt_ranges,
-                            multibuffer_context_lines(cx),
-                            cx,
-                        );
-                        if let Some(buffer_diff) = buffer_diff {
-                            multibuffer.add_diff(buffer_diff, cx);
+                            hunks
+                                .map(|hunk| hunk.buffer_range.to_point(&snapshot))
+                                .collect::<Vec<_>>()
                         }
-                    });
-                })?;
+                    } else {
+                        vec![language::Point::zero()..snapshot.max_point()]
+                    };
+                    (ranges, path)
+                });
+
+                // Batch the insertion of excerpts and yield between batches, to avoid blocking the main thread when a single file has many hunks.
+                const EXCERPT_BATCH_SIZE: usize = 10;
+                let total = excerpt_ranges.len();
+                let mut batch_end = 0;
+                while batch_end < total {
+                    let is_first_batch = batch_end == 0;
+                    batch_end = (batch_end + EXCERPT_BATCH_SIZE).min(total);
+                    let ranges = excerpt_ranges[..batch_end].to_vec();
+                    this.update(cx, |this, cx| {
+                        this.multibuffer.update(cx, |multibuffer, cx| {
+                            multibuffer.set_excerpts_for_path(
+                                path.clone(),
+                                buffer.clone(),
+                                ranges,
+                                multibuffer_context_lines(cx),
+                                cx,
+                            );
+                            if is_first_batch {
+                                if let Some(buffer_diff) = buffer_diff.clone() {
+                                    multibuffer.add_diff(buffer_diff, cx);
+                                }
+                            }
+                        });
+                    })?;
+                    if batch_end < total {
+                        yield_now().await;
+                    }
+                }
             }
 
             this.update(cx, |this, cx| {