editor: Use a single newline between each copied line from a multi-cursor selection (#41204)

Closes #40923

Release Notes:

- Fixed the amount of newlines between copied lines from a multi-cursor
selection of multiple full-line copies.

---


https://github.com/user-attachments/assets/ab7474d6-0e49-4c29-9700-7692cd019cef

crates/editor/src/editor.rs

@@ -12585,6 +12585,7 @@ impl Editor {
         {
             let max_point = buffer.max_point();
             let mut is_first = true;
+            let mut prev_selection_was_entire_line = false;
             for selection in &mut selections {
                 let is_entire_line =
                     (selection.is_empty() && cut_no_selection_line) || self.selections.line_mode();
@@ -12599,9 +12600,10 @@ impl Editor {
                 }
                 if is_first {
                     is_first = false;
-                } else {
+                } else if !prev_selection_was_entire_line {
                     text += "\n";
                 }
+                prev_selection_was_entire_line = is_entire_line;
                 let mut len = 0;
                 for chunk in buffer.text_for_range(selection.start..selection.end) {
                     text.push_str(chunk);
@@ -12684,6 +12686,7 @@ impl Editor {
         {
             let max_point = buffer.max_point();
             let mut is_first = true;
+            let mut prev_selection_was_entire_line = false;
             for selection in &selections {
                 let mut start = selection.start;
                 let mut end = selection.end;
@@ -12742,9 +12745,10 @@ impl Editor {
                 for trimmed_range in trimmed_selections {
                     if is_first {
                         is_first = false;
-                    } else {
+                    } else if !prev_selection_was_entire_line {
                         text += "\n";
                     }
+                    prev_selection_was_entire_line = is_entire_line;
                     let mut len = 0;
                     for chunk in buffer.text_for_range(trimmed_range.start..trimmed_range.end) {
                         text.push_str(chunk);
@@ -12818,7 +12822,11 @@ impl Editor {
                             let end_offset = start_offset + clipboard_selection.len;
                             to_insert = &clipboard_text[start_offset..end_offset];
                             entire_line = clipboard_selection.is_entire_line;
-                            start_offset = end_offset + 1;
+                            start_offset = if entire_line {
+                                end_offset
+                            } else {
+                                end_offset + 1
+                            };
                             original_indent_column = Some(clipboard_selection.first_line_indent);
                         } else {
                             to_insert = &*clipboard_text;

crates/editor/src/editor_tests.rs

@@ -27375,6 +27375,60 @@ async fn test_copy_line_without_trailing_newline(cx: &mut TestAppContext) {
     cx.assert_editor_state("line1\nline2\nˇ");
 }
 
+#[gpui::test]
+async fn test_multi_selection_copy_with_newline_between_copied_lines(cx: &mut TestAppContext) {
+    init_test(cx, |_| {});
+
+    let mut cx = EditorTestContext::new(cx).await;
+
+    cx.set_state("ˇline1\nˇline2\nˇline3\n");
+
+    cx.update_editor(|e, window, cx| e.copy(&Copy, window, cx));
+
+    let clipboard_text = cx
+        .read_from_clipboard()
+        .and_then(|item| item.text().as_deref().map(str::to_string));
+
+    assert_eq!(
+        clipboard_text,
+        Some("line1\nline2\nline3\n".to_string()),
+        "Copying multiple lines should include a single newline between lines"
+    );
+
+    cx.set_state("lineA\nˇ");
+
+    cx.update_editor(|e, window, cx| e.paste(&Paste, window, cx));
+
+    cx.assert_editor_state("lineA\nline1\nline2\nline3\nˇ");
+}
+
+#[gpui::test]
+async fn test_multi_selection_cut_with_newline_between_copied_lines(cx: &mut TestAppContext) {
+    init_test(cx, |_| {});
+
+    let mut cx = EditorTestContext::new(cx).await;
+
+    cx.set_state("ˇline1\nˇline2\nˇline3\n");
+
+    cx.update_editor(|e, window, cx| e.cut(&Cut, window, cx));
+
+    let clipboard_text = cx
+        .read_from_clipboard()
+        .and_then(|item| item.text().as_deref().map(str::to_string));
+
+    assert_eq!(
+        clipboard_text,
+        Some("line1\nline2\nline3\n".to_string()),
+        "Copying multiple lines should include a single newline between lines"
+    );
+
+    cx.set_state("lineA\nˇ");
+
+    cx.update_editor(|e, window, cx| e.paste(&Paste, window, cx));
+
+    cx.assert_editor_state("lineA\nline1\nline2\nline3\nˇ");
+}
+
 #[gpui::test]
 async fn test_end_of_editor_context(cx: &mut TestAppContext) {
     init_test(cx, |_| {});