rustyline ignores user's terminal settings for VINTR and VSUSP on Unix

[godmar]

On Unix, users expect to configure the character they type to cause SIGINT to be sent to the foreground process group by typing, e.g. stty intr ^X where ^X is the key combination they wish to use.

rustyline doesn't use signal handling, turns off ISIG, and hardwires Ctrl-C as the interrupt character.
Likewise, the functionality of the VSUSP character (by default Ctrl-Z) appears hardwired as well.

It may be better for it to query the terminal as to which character the user prefers to use and then implement the corresponding actions when it encounters these characters.

PS: this behavior appears to be inherited from the original "guerrilla" linenoise library.

[gwenn]

• Check if this is related to termios VKILL, VINTR, ...
  https://github.com/troglobit/editline/blob/master/src/sysunix.c#L93-L99
• Check if linefeed / liner / termwiz / crossterm / ... / editline / readline keep ISIG on

[godmar]

You are correct in that one would use the termios(3) and specifically tcgetattr to obtain the current settings of these shortcut keys.

[gwenn]

Ok, so we should be able to retrieve current config here and overwrite default key bindings accordingly.

[gwenn]

Could you please give a try to #535 ?

rustyline % RUST_LOG=rustyline=debug cargo run --example example 2> debug.log

...
[DEBUG rustyline::tty::unix] VINTR: KeyEvent(Char('C'), CTRL)
[DEBUG rustyline::tty::unix] VQUIT: KeyEvent(Char('\\'), CTRL)
[DEBUG rustyline::tty::unix] VSUSP: KeyEvent(Char('Z'), CTRL)
...
[DEBUG rustyline::tty::unix] terminal key binding: KeyEvent(Char('Z'), CTRL) => Suspend
...
[DEBUG rustyline::tty::unix] terminal key binding: KeyEvent(Char('C'), CTRL) => Interrupt

[godmar]

This doesn't seem to work; setting intr to ^Y still causes Ctrl-C to interrupt:

[DEBUG rustyline::tty::unix] VINTR: KeyEvent(Char('Y'), CTRL)
[DEBUG rustyline::tty::unix] VQUIT: KeyEvent(Char('\\'), CTRL)
[DEBUG rustyline::tty::unix] VSUSP: KeyEvent(Char('Z'), CTRL)
[DEBUG rustyline::edit] old layout: Layout { prompt_size: Position { col: 0, row: 0 }, default_prompt: false, cursor: Position { col: 0, row: 0 }, end: Position { col: 0, row: 0 } }
[DEBUG rustyline::edit] new layout: Layout { prompt_size: Position { col: 3, row: 0 }, default_prompt: true, cursor: Position { col: 3, row: 0 }, end: Position { col: 3, row: 0 } }
1> [DEBUG rustyline::tty::unix] key: KeyEvent(Char('C'), CTRL)
[DEBUG rustyline::keymap] Emacs command: Interrupt

CTRL-C

This may be because of:

            E(K::Char('C'), M::CTRL) => Cmd::Interrupt,

[gwenn]

@godmar Could you give it another try ?

[godmar]

This now works, except for EOF.
Try this perhaps:

diff --git a/examples/example.rs b/examples/example.rs
index 7b3ccc8..f937b8f 100644
--- a/examples/example.rs
+++ b/examples/example.rs
@@ -113,11 +113,11 @@ fn main() -> rustyline::Result<()> {
                 println!("Line: {}", line);
             }
             Err(ReadlineError::Interrupted) => {
-                println!("CTRL-C");
+                println!("Interrupted");
                 break;
             }
             Err(ReadlineError::Eof) => {
-                println!("CTRL-D");
+                println!("Encountered Eof");
                 break;
             }
             Err(err) => {
diff --git a/src/keymap.rs b/src/keymap.rs
index 67c9775..d459062 100644
--- a/src/keymap.rs
+++ b/src/keymap.rs
@@ -1045,6 +1045,7 @@ impl InputState {
             }),
             #[cfg(any(windows, test))]
             E(K::Char('C'), M::CTRL) => Cmd::Interrupt,
+            #[cfg(any(windows, test))]
             E(K::Char('D'), M::CTRL) => {
                 if self.is_emacs_mode() && !wrt.line().is_empty() {
                     Cmd::Kill(if positive {
diff --git a/src/tty/unix.rs b/src/tty/unix.rs
index 584076d..e1c31ae 100644
--- a/src/tty/unix.rs
+++ b/src/tty/unix.rs
@@ -1151,6 +1151,7 @@ impl Term for PosixTerminal {
         raw.control_chars[SCI::VTIME as usize] = 0; // with blocking read
 
         let mut key_map: HashMap<KeyEvent, Cmd> = HashMap::with_capacity(3);
+        map_key(&mut key_map, &raw, SCI::VEOF, "VEOF", Cmd::EndOfFile);
         map_key(&mut key_map, &raw, SCI::VINTR, "VINTR", Cmd::Interrupt);
         map_key(&mut key_map, &raw, SCI::VQUIT, "VQUIT", Cmd::Interrupt);
         map_key(&mut key_map, &raw, SCI::VSUSP, "VSUSP", Cmd::Suspend);

[gwenn]

Ctrl-d is more complicated. See readline emacs and vi bindings.

[gwenn]

See also how editline handle VEOF.

[godmar]

See also how editline handle VEOF.

Independent of any other logic to which you may be referring, editline seems to respect the termios settings by doing: rl_eof = old.c_cc[VEOF];

[gwenn]

https://github.com/kkawakam/rustyline/pull/535/files#diff-4d757ff9c4eb4e65aec9dcecd65fed9feefe7d614d6da04190d9070e8e891c97R467

Trigger Eof error only if line is empty.

[gwenn]

Version 9.1.0 released.