From 2a8e0824a629e3553ce06b33039dabed9704a5a0 Mon Sep 17 00:00:00 2001
From: Antonio Scandurra <me@as-cii.com>
Date: Wed, 24 May 2023 14:59:57 +0200
Subject: [PATCH] Fix opening excerpt when the cursor is at the end of a
 multi-buffer

This was caused by seeking with a right bias, which in the case of the
last excerpt in the buffer would seek past the end of the buffer.  This
commit changes the behavior to move the cursor back to the previous excerpt
if we overshoot, to ensure we always land on an excerpt.
---
 crates/editor/src/multi_buffer.rs | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/crates/editor/src/multi_buffer.rs b/crates/editor/src/multi_buffer.rs
index 6a61775697..6b1ad6c5b2 100644
--- a/crates/editor/src/multi_buffer.rs
+++ b/crates/editor/src/multi_buffer.rs
@@ -1140,6 +1140,10 @@ impl MultiBuffer {
         let mut result = Vec::new();
         let mut cursor = snapshot.excerpts.cursor::<usize>();
         cursor.seek(&start, Bias::Right, &());
+        if cursor.item().is_none() {
+            cursor.prev(&());
+        }
+
         while let Some(excerpt) = cursor.item() {
             if *cursor.start() > end {
                 break;
@@ -5072,16 +5076,19 @@ mod tests {
                     .read(cx)
                     .range_to_buffer_ranges(start_ix..end_ix, cx);
                 let excerpted_buffers_text = excerpted_buffer_ranges
-                    .into_iter()
+                    .iter()
                     .map(|(buffer, buffer_range)| {
                         buffer
                             .read(cx)
-                            .text_for_range(buffer_range)
+                            .text_for_range(buffer_range.clone())
                             .collect::<String>()
                     })
                     .collect::<Vec<_>>()
                     .join("\n");
                 assert_eq!(excerpted_buffers_text, text_for_range);
+                if !expected_excerpts.is_empty() {
+                    assert!(!excerpted_buffer_ranges.is_empty());
+                }
 
                 let expected_summary = TextSummary::from(&expected_text[start_ix..end_ix]);
                 assert_eq!(