From 43d682f6b887ea80260c9d9591fcecbc0100774d Mon Sep 17 00:00:00 2001
From: Conrad Irwin <conrad.irwin@gmail.com>
Date: Fri, 20 Oct 2023 12:46:14 -0600
Subject: [PATCH] Handle pixel-down to last line when no trailing newline

---
 crates/editor/src/display_map.rs | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

diff --git a/crates/editor/src/display_map.rs b/crates/editor/src/display_map.rs
index 184990ea78dc759fa8e1d24f6ae57ac58cc0685c..1d6deb910aa8d55d8f780cdfd8ce169662cfc940 100644
--- a/crates/editor/src/display_map.rs
+++ b/crates/editor/src/display_map.rs
@@ -574,6 +574,7 @@ impl DisplaySnapshot {
     ) -> Line {
         let mut styles = Vec::new();
         let mut line = String::new();
+        let mut ended_in_newline = false;
 
         let range = display_row..display_row + 1;
         for chunk in self.highlighted_chunks(range, false, editor_style) {
@@ -589,6 +590,7 @@ impl DisplaySnapshot {
             } else {
                 Cow::Borrowed(&editor_style.text)
             };
+            ended_in_newline = chunk.chunk.ends_with("\n");
 
             styles.push((
                 chunk.chunk.len(),
@@ -600,6 +602,22 @@ impl DisplaySnapshot {
             ));
         }
 
+        // our pixel positioning logic assumes each line ends in \n,
+        // this is almost always true except for the last line which
+        // may have no trailing newline.
+        if !ended_in_newline && display_row == self.max_point().row() {
+            line.push_str("\n");
+
+            styles.push((
+                "\n".len(),
+                RunStyle {
+                    font_id: editor_style.text.font_id,
+                    color: editor_style.text_color,
+                    underline: editor_style.text.underline,
+                },
+            ));
+        }
+
         text_layout_cache.layout_str(&line, editor_style.text.font_size, &styles)
     }