Trim all trailing whitespace on insert_newline

helix-term/src/commands.rs

@@ -3961,10 +3961,7 @@ pub mod insert {
             let curr = contents.get_char(pos).unwrap_or(' ');
 
             let current_line = text.char_to_line(pos);
-            let line_is_only_whitespace = text
-                .line(current_line)
-                .chars()
-                .all(|char| char.is_ascii_whitespace());
+            let line_start = text.line_to_char(current_line);
 
             let mut new_text = String::new();
 
@@ -3973,15 +3970,10 @@ pub mod insert {
                 .and_then(|config| config.comment_tokens.as_ref())
                 .and_then(|tokens| comment::get_comment_token(text, tokens, current_line));
 
-            // If the current line is all whitespace, insert a line ending at the beginning of
-            // the current line. This makes the current line empty and the new line contain the
-            // indentation of the old line.
-            let (from, to, local_offs) = if line_is_only_whitespace {
-                let line_start = text.line_to_char(current_line);
-                new_text.push_str(doc.line_ending.as_str());
-
-                (line_start, line_start, new_text.chars().count())
-            } else {
+            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 line = text.line(current_line);
 
                 let indent = match line.first_non_whitespace_char() {
@@ -4034,20 +4026,34 @@ pub mod insert {
                     new_text.chars().count()
                 };
 
-                (pos, pos, local_offs)
+                (
+                    first_trailing_whitespace_char,
+                    pos,
+                    // Note that `first_trailing_whitespace_char` is at least `pos` so the
+                    // unsigned subtraction (`pos - first_trailing_whitespace_char`) cannot
+                    // underflow.
+                    local_offs as isize - (pos - first_trailing_whitespace_char) as isize,
+                )
+            } else {
+                // If the current line is all whitespace, insert a line ending at the beginning of
+                // the current line. This makes the current line empty and the new line contain the
+                // indentation of the old line.
+                new_text.push_str(doc.line_ending.as_str());
+
+                (line_start, line_start, new_text.chars().count() as isize)
             };
 
             let new_range = if range.cursor(text) > range.anchor {
                 // when appending, extend the range by local_offs
                 Range::new(
                     range.anchor + global_offs,
-                    range.head + local_offs + global_offs,
+                    (range.head as isize + local_offs) as usize + global_offs,
                 )
             } else {
                 // when inserting, slide the range by local_offs
                 Range::new(
-                    range.anchor + local_offs + global_offs,
-                    range.head + local_offs + global_offs,
+                    (range.anchor as isize + local_offs) as usize + global_offs,
+                    (range.head as isize + local_offs) as usize + global_offs,
                 )
             };
 

helix-term/tests/test/commands.rs

@@ -2,6 +2,7 @@ use helix_term::application::Application;
 
 use super::*;
 
+mod insert;
 mod movement;
 mod write;
 

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

@@ -0,0 +1,53 @@
+use super::*;
+
+#[tokio::test(flavor = "multi_thread")]
+async fn insert_newline_trim_trailing_whitespace() -> anyhow::Result<()> {
+    // Trailing whitespace is trimmed.
+    test((
+        indoc! {"\
+            hello·······#[|
+            ]#world
+            "}
+        .replace('·', " "),
+        "i<ret>",
+        indoc! {"\
+            hello
+            #[|
+            ]#world
+            "}
+        .replace('·', " "),
+    ))
+    .await?;
+
+    // Whitespace that would become trailing is trimmed too.
+    test((
+        indoc! {"\
+            hello········#[|w]#orld
+            "}
+        .replace('·', " "),
+        "i<ret>",
+        indoc! {"\
+            hello
+            #[|w]#orld
+            "}
+        .replace('·', " "),
+    ))
+    .await?;
+
+    // Only whitespace before the cursor is trimmed.
+    test((
+        indoc! {"\
+            hello········#[|·]#····world
+            "}
+        .replace('·', " "),
+        "i<ret>",
+        indoc! {"\
+            hello
+            #[|·]#····world
+            "}
+        .replace('·', " "),
+    ))
+    .await?;
+
+    Ok(())
+}

helix-term/tests/test/languages/yaml.rs

@@ -795,7 +795,7 @@ async fn auto_indent() -> anyhow::Result<()> {
             "##},
             "i<ret>",
             indoc! {"\
-                foo: 
+                foo:
                   #[|b]#ar
             "},
         ),