[BUG] While using cursive, stacktrace (on panic) are never printed to (non-alternate) screen #754

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1. hasezoey

   added

   bug

   on Sep 12, 2023
2. gyscos commented on Sep 12, 2023

   

   gyscos

   on Sep 12, 2023

   Last edited by gyscos

   Owner

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   Hi, and thanks for the report!

   I think the issue is that the message is printed at the time of the panic, before unwinding (and calling drop). Then, unwinding happens, and the screen is cleared.

   I see two possible workarounds:

   • Redirect stderr (for example manually to a file with 2> err - fine for development, not ideal user experience
   • Override the panic handler, save the message/backtrace, and print it after unwindinging. Haven't fully checked how feasible that is, but it might make things more seamless.
     One problem is that "after clearing the screen" is currently in the drop implementation of the runner. I guess we could re-raise the panic there?
3. necauqua commented on Oct 23, 2023

   

   necauqua

   on Oct 23, 2023

   Last edited by necauqua

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   I'm doing the third possible workaround, which works nicely with custom panic hooks (like color-backtrace) - resetting the terminal state in the panic handler :)
   Second reset from the backend drop is harmless as setting the terminal state is (should be) idempotent.

   Seems to work great - except for vscode terminal which does something weird:

   color_backtrace::install()
   // reset the terminal before printing the panic
   let hook = std::panic::take_hook(); // someday the update_hook method will become stable
   std::panic::set_hook(Box::new(move |info| {
       use cursive::backends::crossterm::crossterm::*;
       _ = execute!(
           std::io::stdout(),
           terminal::LeaveAlternateScreen,
           cursor::Show,
           event::DisableMouseCapture,
       );
       _ = terminal::disable_raw_mode();
   
       hook(info)
   }));

   my backend is crossterm, you could copy parts of the drop impl of the backend that you use, for me it's good enough for now well you do use crossterm too :)