Fix selection rotation on the last line

This fixes an issue with terminal resizes when the selection is on the
last line. Alacritty would fail to rotate lines and keep the selection
in the same line index whenever the terminal line count was grown or
shrunk.

This issue occurred due to the range passed to the selection's rotate
function still being based on the old terminal size, which caused the
initial or target state of the rotation to be outside of the terminal
bounds.

Closes alacritty#6698.

alacritty/src/display/mod.rs

@@ -588,11 +588,10 @@ impl Display {
         });
     }
 
+    // XXX: this function must not call to any `OpenGL` related tasks. Renderer updates are
+    // performed in [`Self::process_renderer_update`] right befor drawing.
+    //
     /// Process update events.
-    ///
-    /// XXX: this function must not call to any `OpenGL` related tasks. Only logical update
-    /// of the state is being performed here. Rendering update takes part right before the
-    /// actual rendering.
     pub fn handle_update<T>(
         &mut self,
         terminal: &mut Term<T>,
@@ -666,14 +665,11 @@ impl Display {
         self.size_info = new_size;
     }
 
+    // NOTE: Renderer updates are split off, since platforms like Wayland require resize and other
+    // OpenGL operations to be performed right before rendering. Otherwise they could lock the
+    // back buffer and render with the previous state. This also solves flickering during resizes.
+    //
     /// Update the state of the renderer.
-    ///
-    /// NOTE: The update to the renderer is split from the display update on purpose, since
-    /// on some platforms, like Wayland, resize and other OpenGL operations must be performed
-    /// right before rendering, otherwise they could lock the back buffer resulting in
-    /// rendering with the buffer of old size.
-    ///
-    /// This also resolves any flickering, since the resize is now synced with frame callbacks.
     pub fn process_renderer_update(&mut self) {
         let renderer_update = match self.pending_renderer_update.take() {
             Some(renderer_update) => renderer_update,

alacritty_terminal/src/term/mod.rs

@@ -611,21 +611,22 @@ impl<T> Term<T> {
         delta = cmp::min(cmp::max(delta, min_delta), history_size as i32);
         self.vi_mode_cursor.point.line += delta;
 
+        let is_alt = self.mode.contains(TermMode::ALT_SCREEN);
+        self.grid.resize(!is_alt, num_lines, num_cols);
+        self.inactive_grid.resize(is_alt, num_lines, num_cols);
+
         // Invalidate selection and tabs only when necessary.
         if old_cols != num_cols {
             self.selection = None;
 
             // Recreate tabs list.
             self.tabs.resize(num_cols);
         } else if let Some(selection) = self.selection.take() {
-            let range = Line(0)..Line(num_lines as i32);
+            let max_lines = cmp::max(num_lines, old_lines) as i32;
+            let range = Line(0)..Line(max_lines);
             self.selection = selection.rotate(self, &range, -delta);
         }
 
-        let is_alt = self.mode.contains(TermMode::ALT_SCREEN);
-        self.grid.resize(!is_alt, num_lines, num_cols);
-        self.inactive_grid.resize(is_alt, num_lines, num_cols);
-
         // Clamp vi cursor to viewport.
         let vi_point = self.vi_mode_cursor.point;
         let viewport_top = Line(-(self.grid.display_offset() as i32));