Share the restore_term code between panic and normal exits (#3612)

It was starting to diverge as the normal exit code was restoring the prompt but the panic code
wasn't, and the panic code was disabling bracketed paste but the normal code wasn't.

This changes the panic path slightly in that we won't disable raw mode if exiting alternate screen
and disabling bracketed paste fails. If that happens, things are so busted I don't think it matters
anyway.

helix-term/src/application.rs

@@ -85,6 +85,22 @@ fn setup_integration_logging() {
         .apply();
 }
 
+fn restore_term() -> Result<(), Error> {
+    let mut stdout = stdout();
+    // reset cursor shape
+    write!(stdout, "\x1B[0 q")?;
+    // Ignore errors on disabling, this might trigger on windows if we call
+    // disable without calling enable previously
+    let _ = execute!(stdout, DisableMouseCapture);
+    execute!(
+        stdout,
+        DisableBracketedPaste,
+        terminal::LeaveAlternateScreen
+    )?;
+    terminal::disable_raw_mode()?;
+    Ok(())
+}
+
 impl Application {
     pub fn new(args: Args, config: Config) -> Result<Self, Error> {
         #[cfg(feature = "integration")]
@@ -389,7 +405,7 @@ impl Application {
         match signal {
             signal::SIGTSTP => {
                 self.compositor.save_cursor();
-                self.restore_term().unwrap();
+                restore_term().unwrap();
                 low_level::emulate_default_handler(signal::SIGTSTP).unwrap();
             }
             signal::SIGCONT => {
@@ -803,18 +819,6 @@ impl Application {
         Ok(())
     }
 
-    fn restore_term(&mut self) -> Result<(), Error> {
-        let mut stdout = stdout();
-        // reset cursor shape
-        write!(stdout, "\x1B[0 q")?;
-        // Ignore errors on disabling, this might trigger on windows if we call
-        // disable without calling enable previously
-        let _ = execute!(stdout, DisableMouseCapture);
-        execute!(stdout, terminal::LeaveAlternateScreen)?;
-        terminal::disable_raw_mode()?;
-        Ok(())
-    }
-
     pub async fn run<S>(&mut self, input_stream: &mut S) -> Result<i32, Error>
     where
         S: Stream<Item = crossterm::Result<crossterm::event::Event>> + Unpin,
@@ -826,20 +830,14 @@ impl Application {
         std::panic::set_hook(Box::new(move |info| {
             // We can't handle errors properly inside this closure.  And it's
             // probably not a good idea to `unwrap()` inside a panic handler.
-            // So we just ignore the `Result`s.
-            let _ = execute!(std::io::stdout(), DisableMouseCapture);
-            let _ = execute!(
-                std::io::stdout(),
-                terminal::LeaveAlternateScreen,
-                DisableBracketedPaste
-            );
-            let _ = terminal::disable_raw_mode();
+            // So we just ignore the `Result`.
+            let _ = restore_term();
             hook(info);
         }));
 
         self.event_loop(input_stream).await;
         self.close().await?;
-        self.restore_term()?;
+        restore_term()?;
 
         Ok(self.editor.exit_code)
     }