Port, board and/or hardware

rp2

MicroPython version

MicroPython v1.25.0 on 2025-04-15; Raspberry Pi Pico 2 W with RP2350

Reproduction

Call os.dupterm() with UART or other compatible stream object:

from machine import UART
import os
os.dupterm(UART(0), 0)

Run some code:

import time
i = 0
while True:
    print(i)
    i += 1
    time.sleep(1)

Expected behaviour

While code is running, pressing Ctrl+C in the USB REPL works as expected:

0
1
2
Traceback (most recent call last):
  File "<stdin>", line 6, in <module>
KeyboardInterrupt:
>>>

Observed behaviour

While code is running, pressing Ctrl+C in the UART REPL fails to send the KeyboardInterrupt and halt execution.

Below, I pressed Ctrl+C a few times in the UART REPL, then once in the USB REPL. It then output extra >>>'s for each time I hit Ctrl+C in the UART REPL, indicating the KeyboardInterrupt's were getting buffered or something?

0
1
2
3
Traceback (most recent call last):
  File "<stdin>", line 6, in <module>
KeyboardInterrupt:
>>>
>>>
>>>
>>>
>>>

Additional Information

Although the provided replication code uses UART, this also happens with a Bluetooth REPL connection and is actually what we need to be fixed. This was just the simplest way to replicate.

Code of Conduct

Yes, I agree