QtConsole Freeze and Error After calling input() "QTextCursor::setPosition: out of range"

[TheMatt2]

Issue with QtConsole freezing when using input() to prompt the user for input after printing something asynchronously from a second thread.

It seems to be important that the prompt given to input() is a blank string.

The following code fragment can replicate the issue.

import time, threading

def f():
    time.sleep(2)
    print("Hello")

threading.Thread(target = f).start(); x = input()

When you run the code, you do not get a prompt back, and the console QtConsole was launched from logs the message QTextCursor::setPosition: Position '429' out of range

Jupyter QtConsole 5.6.0.dev0

Tested against commit version: 56e5a5e

Originally posted by @TheMatt2 in #607 (comment)