Crash when typing before prompt is ready

[sophiajt]

If there is leftover text in the buffer, or you type too soon before rustyline is ready, I'm seeing that it looks like we trip over this and crash:

rustyline/src/tty/unix.rs

Lines 653 to 658 in 9d67a19

	if rdr.next_char()? != '\x1b' {
	return Err(error::ReadlineError::from(io::ErrorKind::InvalidData));
	}
	if rdr.next_char()? != '[' {
	return Err(error::ReadlineError::from(io::ErrorKind::InvalidData));
	}

It seems like it might be where the ansi doesn't see the correct answers coming back.

Here's what the output looks like:

I wonder if it might be possible to clear (or maybe lock?) the input buffer before rustyline is ready, so that it doesn't interfere with rustyline getting ready to read input.

[gwenn]

Maybe related to #246 (same cause).
A quick fix would be to skip checking the cursor position if some bytes are already available in stdin.

[gwenn]

https://github.com/prompt-toolkit/python-prompt-toolkit/blob/master/prompt_toolkit/application/application.py#L874

        # Note: only do this if the input queue is not empty, and a return
        # value has not been set. Otherwise, we won't be able to read the
        # response anyway.

[gwenn]

See #250

[sophiajt]

I haven't seen this issue since the PR, so this may have fixed it.

[gwenn]

#250 also fixes a similar issue:
#246 (comment)
Thank you for your detailed report.
I will release version 5.0.1.

[gwenn]

Version 5.0.1 released

[sophiajt]

Thank you!