Don't panic on empty document

helix-view/src/document.rs

@@ -149,7 +149,7 @@ impl Document {
             let file = File::open(&path).context(format!("unable to open {:?}", path))?;
             let mut doc = Rope::from_reader(BufReader::new(file))?;
             // add missing newline at the end of file
-            if doc.byte(doc.len_bytes() - 1) != b'\n' {
+            if doc.len_bytes() == 0 || doc.byte(doc.len_bytes() - 1) != b'\n' {
                 doc.insert_char(doc.len_chars(), '\n');
             }
             doc