Fix block selection including last column

The block selection will now only insert extra newline characters after
each line if the last line isn't already included. This resolves an
issue with duplicate newlines, since newlines are automatically appended
when the last column is part of a selection.

Fixes #3304.

2 files changed, 7 insertions, 1 deletions

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 2545d393..8bf47af2 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -52,6 +52,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Handling of URLs with single quotes
 - Parser reset between DCS escapes
 - Parser stopping at unknown DEC private modes/SGR character attributes
+- Block selection appending duplicate newlines when last column is selected
 
 ### Removed
 
diff --git a/alacritty_terminal/src/term/mod.rs b/alacritty_terminal/src/term/mod.rs
index ae1d7151..b2184ad9 100644
--- a/alacritty_terminal/src/term/mod.rs
+++ b/alacritty_terminal/src/term/mod.rs
@@ -984,7 +984,12 @@ impl<T> Term<T> {
 
         if is_block {
             for line in (end.line + 1..=start.line).rev() {
-                res += &(self.line_to_string(line, start.col..end.col, start.col.0 != 0) + "\n");
+                res += &self.line_to_string(line, start.col..end.col, start.col.0 != 0);
+
+                // If the last column is included, newline is appended automatically
+                if end.col != self.cols() - 1 {
+                    res += "\n";
+                }
             }
             res += &self.line_to_string(end.line, start.col..end.col, true);
         } else {