From b8c3167a9de7dca14f4b3a2943dcfadd0ec5fe7a Mon Sep 17 00:00:00 2001
From: Lukas Wirth <lukas@zed.dev>
Date: Fri, 8 May 2026 16:18:44 +0200
Subject: [PATCH] diagnostics: Always expand at least
 `multibuffer_context_lines` per diagnostic (#56172)

Otherwise we can sometimes end up with single line excerpts which looks
very off



Release Notes:

- Improved the minimum size of diagnostics pane excerpts
---
 Cargo.lock                            |  1 +
 crates/diagnostics/Cargo.toml         |  1 +
 crates/diagnostics/src/diagnostics.rs | 27 +++++++++++++++------------
 3 files changed, 17 insertions(+), 12 deletions(-)

diff --git a/Cargo.lock b/Cargo.lock
index f4626a83d5c6b1e5575145efdc540f07ebd2f06c..ea52978db69d453ee8dc17ecf59af47c1780e154 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -4941,6 +4941,7 @@ dependencies = [
  "component",
  "ctor",
  "editor",
+ "futures-lite 1.13.0",
  "gpui",
  "indoc",
  "itertools 0.14.0",
diff --git a/crates/diagnostics/Cargo.toml b/crates/diagnostics/Cargo.toml
index fe850303e83f2bac4629b2a9c7066bda933716de..0c96524ec03bf18c0a11f8ca444e72cb399da947 100644
--- a/crates/diagnostics/Cargo.toml
+++ b/crates/diagnostics/Cargo.toml
@@ -19,6 +19,7 @@ collections.workspace = true
 component.workspace = true
 ctor.workspace = true
 editor.workspace = true
+futures-lite.workspace = true
 gpui.workspace = true
 indoc.workspace = true
 itertools.workspace = true
diff --git a/crates/diagnostics/src/diagnostics.rs b/crates/diagnostics/src/diagnostics.rs
index 642d16b6e254763f2758b3998708915acb71da5d..de99274d86aa1a277ad6a902e9f5db4983837207 100644
--- a/crates/diagnostics/src/diagnostics.rs
+++ b/crates/diagnostics/src/diagnostics.rs
@@ -981,24 +981,26 @@ async fn context_range_for_entry(
     snapshot: BufferSnapshot,
     cx: &mut AsyncApp,
 ) -> Range<text::Anchor> {
-    let range = if let Some(rows) = heuristic_syntactic_expand(
+    let expanded_range = heuristic_syntactic_expand(
         range.clone(),
         DIAGNOSTIC_EXPANSION_ROW_LIMIT,
         snapshot.clone(),
         cx,
     )
-    .await
-    .filter(|rows| rows.start() != rows.end())
-    {
-        Range {
-            start: Point::new(*rows.start(), 0),
-            end: snapshot.clip_point(Point::new(*rows.end(), u32::MAX), Bias::Left),
-        }
+    .await;
+    let row_range = expanded_range.unwrap_or_else(|| range.start.row..=range.end.row);
+    let row_count = row_range.end().saturating_sub(*row_range.start()) + 1;
+    let target_row_count = context.saturating_mul(2).saturating_add(1);
+    let row_range = if let Some(rows_to_add) = target_row_count.checked_sub(row_count) {
+        let rows_before = rows_to_add.div_ceil(2);
+        let rows_after = rows_to_add / 2;
+        row_range.start().saturating_sub(rows_before)..=row_range.end().saturating_add(rows_after)
     } else {
-        Range {
-            start: Point::new(range.start.row.saturating_sub(context), 0),
-            end: snapshot.clip_point(Point::new(range.end.row + context, u32::MAX), Bias::Left),
-        }
+        row_range
+    };
+    let range = Range {
+        start: Point::new(*row_range.start(), 0),
+        end: snapshot.clip_point(Point::new(*row_range.end(), u32::MAX), Bias::Left),
     };
     snapshot.anchor_after(range.start)..snapshot.anchor_before(range.end)
 }
@@ -1133,6 +1135,7 @@ async fn heuristic_syntactic_expand(
             return None;
         };
         node = parent;
+        futures_lite::future::yield_now().await;
     }
 }