fix: trim whitespace up to the last selection on insert_newline (#13673)

helix-term/src/commands.rs

@@ -4206,6 +4206,7 @@ pub mod insert {
             None
         };
 
+        let mut last_pos = 0;
         let mut transaction = Transaction::change_by_selection(contents, selection, |range| {
             // Tracks the number of trailing whitespace characters deleted by this selection.
             let mut chars_deleted = 0;
@@ -4227,7 +4228,8 @@ pub mod insert {
             let (from, to, local_offs) = if let Some(idx) =
                 text.slice(line_start..pos).last_non_whitespace_char()
             {
-                let first_trailing_whitespace_char = (line_start + idx + 1).min(pos);
+                let first_trailing_whitespace_char = (line_start + idx + 1).clamp(last_pos, pos);
+                last_pos = pos;
                 let line = text.line(current_line);
 
                 let indent = match line.first_non_whitespace_char() {

helix-term/tests/test/commands/insert.rs

@@ -172,6 +172,18 @@ async fn insert_newline_trim_trailing_whitespace() -> anyhow::Result<()> {
     Ok(())
 }
 
+#[tokio::test(flavor = "multi_thread")]
+async fn insert_newline_trim_whitespace_to_previous_selection() -> anyhow::Result<()> {
+    test((
+        indoc! {"\"#[a|]# #(a|)# #(a|)#\""},
+        "c<ret>",
+        indoc! {"\"\n#[\n|]##(\n|)##(\"|)#"},
+    ))
+    .await?;
+
+    Ok(())
+}
+
 #[tokio::test(flavor = "multi_thread")]
 async fn insert_newline_continue_line_comment() -> anyhow::Result<()> {
     // `insert_newline` continues a single line comment