A long time ago when there was only the `stm` port, Ctrl-C would trigger a
preemptive NLR jump to break out of running code. Then in commit
124df6f8d0 a more general approach to
asynchronous `KeyboardInterrupt` exceptions was implemented, and `stmhal`
supported both approaches, with the general (soft) interrupt taking
priority.
Then in commit bc1488a05f `pyboard.py` was
updated with a corresponding change to make it issue a double Ctrl-C to
break out of any existing code when entering the raw REPL (two Ctrl-C
characters were sent in order to more reliably trigger the preemptive NLR
jump).
No other port has preemptive NLR jumps and so a double Ctrl-C doesn't
really behave any differently to a single Ctrl-C: with USB CDC the double
Ctrl-C would most likely be in the same USB packet and so processed in the
same low-level USB callback, so it's just setting the keyboard interrupt
flag twice in a row. The VM/runtime then just sees one keyboard interrupt
and acts as though only one Ctrl-C was sent.
This commit changes the double Ctrl-C to a single Ctrl-C in `pyboard.py`
and `mpremote`. That keeps things as simple as they need to be.
Signed-off-by: Damien George <damien@micropython.org>
d92694c3e8