From 368b4447ff3caa9b13ea3e15097c4722cb71ac0b Mon Sep 17 00:00:00 2001
From: Max Brunsfeld <maxbrunsfeld@gmail.com>
Date: Wed, 15 Dec 2021 15:41:38 -0800
Subject: [PATCH] Clip buffer points in DisplayMap::{prev,next}_row_boundary

---
 crates/editor/src/display_map.rs | 16 +++++++++++++++-
 1 file changed, 15 insertions(+), 1 deletion(-)

diff --git a/crates/editor/src/display_map.rs b/crates/editor/src/display_map.rs
index 9e00719728..c9a139ceda 100644
--- a/crates/editor/src/display_map.rs
+++ b/crates/editor/src/display_map.rs
@@ -208,11 +208,18 @@ impl DisplaySnapshot {
         loop {
             *display_point.column_mut() = 0;
             let mut point = display_point.to_point(self);
+            point = self.buffer_snapshot.clip_point(point, Bias::Left);
             point.column = 0;
             let next_display_point = self.point_to_display_point(point, Bias::Left);
             if next_display_point == display_point {
                 return (display_point, point);
             }
+            debug_assert!(
+                next_display_point < display_point,
+                "{:?} > {:?}",
+                next_display_point,
+                display_point
+            );
             display_point = next_display_point;
         }
     }
@@ -220,12 +227,19 @@ impl DisplaySnapshot {
     pub fn next_row_boundary(&self, mut display_point: DisplayPoint) -> (DisplayPoint, Point) {
         loop {
             *display_point.column_mut() = self.line_len(display_point.row());
-            let mut point = display_point.to_point(self);
+            let mut point = self.display_point_to_point(display_point, Bias::Right);
+            point = self.buffer_snapshot.clip_point(point, Bias::Right);
             point.column = self.buffer_snapshot.line_len(point.row);
             let next_display_point = self.point_to_display_point(point, Bias::Right);
             if next_display_point == display_point {
                 return (display_point, point);
             }
+            debug_assert!(
+                next_display_point > display_point,
+                "{:?} < {:?}",
+                next_display_point,
+                display_point
+            );
             display_point = next_display_point;
         }
     }