Enforce trailing newline on save

src/state.rs

@@ -224,6 +224,10 @@ impl Buffer {
     }
 
     pub fn save(&mut self) -> Result<(), Error> {
+        // Ensure trailing newline exists
+        if self.text.chars.last().map_or(false, |c| *c != '\n') {
+            self.insert(self.text.chars.len(), ['\n']);
+        }
         let path = self.path.as_ref().expect("buffer must have path to save");
         if let Some(parent) = path.parent() {
             std::fs::create_dir_all(parent)?;

src/ui/doc.rs

@@ -149,6 +149,14 @@ impl Element for Doc {
                     )
                     .into(),
                 )
+            } else if buffer.path.is_none() {
+                Some(
+                    Action::Show(
+                        None,
+                        "Error: buffer does not have a path (TODO: implement save_as)".to_string(),
+                    )
+                    .into(),
+                )
             } else {
                 buffer.save().err().map(|err| {
                     Action::Show(Some("Could not save file".to_string()), err.to_string()).into()