Allow last line in file to lack a line break character.

2 files changed, 23 insertions, 11 deletions

diff --git a/helix-core/src/movement.rs b/helix-core/src/movement.rs
index acc95e7e..b810876c 100644
--- a/helix-core/src/movement.rs
+++ b/helix-core/src/movement.rs
@@ -65,7 +65,7 @@ pub fn move_vertically(
         Direction::Backward => row.saturating_sub(count),
         Direction::Forward => std::cmp::min(
             row.saturating_add(count),
-            slice.len_lines().saturating_sub(2),
+            slice.len_lines().saturating_sub(1),
         ),
     };
 
@@ -402,12 +402,13 @@ mod test {
         let moves_and_expected_coordinates = IntoIter::new([
             ((Direction::Forward, 1usize), (1, 0)),
             ((Direction::Forward, 2usize), (3, 0)),
+            ((Direction::Forward, 1usize), (4, 0)),
             ((Direction::Backward, 999usize), (0, 0)),
-            ((Direction::Forward, 3usize), (3, 0)),
-            ((Direction::Forward, 0usize), (3, 0)),
-            ((Direction::Backward, 0usize), (3, 0)),
-            ((Direction::Forward, 5), (4, 0)),
-            ((Direction::Forward, 999usize), (4, 0)),
+            ((Direction::Forward, 4usize), (4, 0)),
+            ((Direction::Forward, 0usize), (4, 0)),
+            ((Direction::Backward, 0usize), (4, 0)),
+            ((Direction::Forward, 5), (5, 0)),
+            ((Direction::Forward, 999usize), (5, 0)),
         ]);
 
         for ((direction, amount), coordinates) in moves_and_expected_coordinates {
@@ -439,7 +440,8 @@ mod test {
             ((Axis::V, Direction::Forward, 1usize), (3, 8)),
             // Behaviour is preserved even through long jumps
             ((Axis::V, Direction::Backward, 999usize), (0, 8)),
-            ((Axis::V, Direction::Forward, 999usize), (4, 8)),
+            ((Axis::V, Direction::Forward, 4usize), (4, 8)),
+            ((Axis::V, Direction::Forward, 999usize), (5, 0)),
         ]);
 
         for ((axis, direction, amount), coordinates) in moves_and_expected_coordinates {
diff --git a/helix-core/src/syntax.rs b/helix-core/src/syntax.rs
index 9dbb2c03..d4379a8e 100644
--- a/helix-core/src/syntax.rs
+++ b/helix-core/src/syntax.rs
@@ -1758,10 +1758,20 @@ impl<I: Iterator<Item = HighlightEvent>> Iterator for Merge<I> {
                 self.next_event = self.iter.next();
                 Some(event)
             }
-            // can happen if deleting and cursor at EOF, and diagnostic reaches past the end
-            (None, Some((_, _))) => {
-                self.next_span = None;
-                None
+            // Can happen if cursor at EOF and/or diagnostic reaches past the end.
+            // We need to actually emit events for the cursor-at-EOF situation,
+            // even though the range is past the end of the text.  This needs to be
+            // handled appropriately by the drawing code by not assuming that
+            // all `Source` events point to valid indices in the rope.
+            (None, Some((span, range))) => {
+                let event = HighlightStart(Highlight(*span));
+                self.queue.push(HighlightEnd);
+                self.queue.push(Source {
+                    start: range.start,
+                    end: range.end,
+                });
+                self.next_span = self.spans.next();
+                Some(event)
             }
             (None, None) => None,
             e => unreachable!("{:?}", e),