[Python-Dev] Issue with _thread.interrupt_main (29926)

[Terry Reedy]

Steven, thanks for verifying bug on *nix.

On 3/28/2017 2:00 AM, Martin Panter wrote:
> On 28 March 2017 at 03:11, Steven D'Aprano <steve at pearwood.info> wrote:
>> On Mon, Mar 27, 2017 at 10:33:44PM -0400, Terry Reedy wrote:
>>> https://bugs.python.org/issue29926 was opened as an IDLE issue, which
>>> means that most watching the new issues list would ignore it.  But I
>>> think it is an issue with _thread.interrupt_main (which IDLE calls in
>>> respond to ^C) not interrupting time.sleep(n) in main thread*.  I tested
>>> on Windows, don't know yet about OP.  Since there is no Expert's Index
>>> listing for _thread (or threading), I am asking here for someone who
>>> knows anything to take a look.
>>>
>>> *
>>>>>> time.sleep(10)
>>> <hit ^C immediately>
>>> <debug print after interrupt_main() shows immediately>
>>> <... remainder of 10 seconds pass>
>>> KeyboardInterrupt
>>
>>
>> I get similar behaviour under Linux. I don't have the debug print, but
>> the KeyboardInterrupt doesn't interrupt the sleep until the 10 seconds
>> are up.
>
> Looking at the implementation, _thread.interrupt_main just calls
> PyErr_SetInterrupt. It doesn’t appear to send a signal. I played with
> “strace” and couldn’t see any evidence of a signal. I guess it just
> sets a flag that will be polled. To actually interrupt the “sleep”
> call, you might need to use “pthread_kill” or similar (at least on
> Unix).

I copied this to the issue.  Eryk Sun suggested a patch for Windows, 
(and the possibility of using pthread_kill).  Can you possibly do one 
for *nix?  This is out of my ballpark, but the bug (relative to console 
behavior) is a nuisance.

-- 
Terry Jan Reedy