Hello,

Here is how to reproduce my problem:

• I start a task A in a new thread.
• Then I start another task B in the main thread (UART REPL).
• Then I press CTRL+C.

Expected behaviour:
Task B gets a KeyboardInterrupt exception. Task A continues running.

Actual behaviour:
KeyboardInterrupt is randomly raised in task A or B.

Here is the full log:

MicroPython v1.12-96-gc3095b37e-dirty on 2020-01-28; ESP32 module with ESP32
Type "help()" for more information.
>>>
paste mode; Ctrl-C to cancel, Ctrl-D to finish
=== import _thread
=== import time
===
=== def long_process(name):
===     for i in range(1000):
===         print(name, i)
===         time.sleep(1)
===
=== _thread.start_new_thread(long_process, ("thread",))
===
=== long_process("main")
main 0
thread 0
main 1
thread 1
main 2
thread 2
main 3
thread 3
Traceback (most recent call last):
  File "<stdin>", line 11, in <module>
  File "<stdin>", line 7, in long_process
KeyboardInterrupt:
>>> thread 4
thread 5
thread 6
thread 7

>>> thread 8
thread 9

>>>
MPY: soft reboot
MicroPython v1.12-96-gc3095b37e-dirty on 2020-01-28; ESP32 module with ESP32
Type "help()" for more information.
>>>
paste mode; Ctrl-C to cancel, Ctrl-D to finish
=== import _thread
=== import time
===
=== def long_process(name):
===     for i in range(1000):
===         print(name, i)
===         time.sleep(1)
===
=== _thread.start_new_thread(long_process, ("thread",))
===
=== long_process("main")
main 0
thread 0
main 1
thread 1
main 2
thread 2
Unhandled exception in thread started by <function long_process at 0x3ffe4e20>
Traceback (most recent call last):
  File "<stdin>", line 7, in long_process
KeyboardInterrupt:
main 3
main 4
main 5
main 6
Traceback (most recent call last):
  File "<stdin>", line 11, in <module>
  File "<stdin>", line 7, in long_process
  File "<stdin>", line 7, in long_process
KeyboardInterrupt:
>>>

During the first try you can see that after the KeyboardInterrupt the thread task is still running. This is the excepted behaviour.

Then after a soft reboot it's the opposite. The thread task got the interrupt and the main task is still running.

My understanding is that the UART received chars are handled in an interrupt, and when the CTRL+C char is detected it raise the KeyboardInterrupt exception in the current running thread.

Is this the normal behaviour or is this a bug?

Thanks,
Yann.