Escape filenames in command completion

This changes the completion items to be rendered with shellword
escaping, so a file `a b.txt` is rendered as `a\ b.txt` which matches
how it should be inputted.

helix-core/src/shellwords.rs

@@ -1,9 +1,9 @@
 use std::borrow::Cow;
 
 /// Auto escape for shellwords usage.
-pub fn escape(input: &str) -> Cow<'_, str> {
+pub fn escape(input: Cow<str>) -> Cow<str> {
     if !input.chars().any(|x| x.is_ascii_whitespace()) {
-        Cow::Borrowed(input)
+        input
     } else if cfg!(unix) {
         Cow::Owned(input.chars().fold(String::new(), |mut buf, c| {
             if c.is_ascii_whitespace() {
@@ -311,15 +311,15 @@ mod test {
     #[test]
     #[cfg(unix)]
     fn test_escaping_unix() {
-        assert_eq!(escape("foobar"), Cow::Borrowed("foobar"));
+        assert_eq!(escape("foobar".into()), Cow::Borrowed("foobar"));
-        assert_eq!(escape("foo bar"), Cow::Borrowed("foo\\ bar"));
+        assert_eq!(escape("foo bar".into()), Cow::Borrowed("foo\\ bar"));
-        assert_eq!(escape("foo\tbar"), Cow::Borrowed("foo\\\tbar"));
+        assert_eq!(escape("foo\tbar".into()), Cow::Borrowed("foo\\\tbar"));
     }
 
     #[test]
     #[cfg(windows)]
     fn test_escaping_windows() {
-        assert_eq!(escape("foobar"), Cow::Borrowed("foobar"));
+        assert_eq!(escape("foobar".into()), Cow::Borrowed("foobar"));
-        assert_eq!(escape("foo bar"), Cow::Borrowed("\"foo bar\""));
+        assert_eq!(escape("foo bar".into()), Cow::Borrowed("\"foo bar\""));
     }
 }

helix-term/src/commands/typed.rs

@@ -2219,6 +2219,7 @@ pub(super) fn command_mode(cx: &mut Context) {
                     completer(editor, part)
                         .into_iter()
                         .map(|(range, file)| {
+                            let file = shellwords::escape(file);
                             // offset ranges to input
                             let offset = input.len() - part.len();
                             let range = (range.start + offset)..;

helix-term/src/ui/prompt.rs

@@ -1,6 +1,5 @@
 use crate::compositor::{Component, Compositor, Context, Event, EventResult};
 use crate::{alt, ctrl, key, shift, ui};
-use helix_core::shellwords;
 use helix_view::input::KeyEvent;
 use helix_view::keyboard::KeyCode;
 use std::{borrow::Cow, ops::RangeFrom};
@@ -336,10 +335,7 @@ impl Prompt {
 
         let (range, item) = &self.completion[index];
 
-        // since we are using shellwords to parse arguments, make sure
+        self.line.replace_range(range.clone(), item);
-        // that whitespace in files is properly escaped.
-        let item = shellwords::escape(item);
-        self.line.replace_range(range.clone(), &item);
 
         self.move_end();
     }