[issue32057] time.sleep(n) interrupted by signal

[Bogdan Popa]

New submission from Bogdan Popa <popa.bogdanp at gmail.com>:

I ran into this while backporting some code from 3.6 to 3.5 and 3.4. The following piece of code prints one line every second, as expected, on 3.6 and 3.5, but it doesn't on 3.4. It looks like the signal is able to wake up the main thread from sleeping:

```
import time
import signal


def handle(signum, mask):
    print("received signal at", time.time())


signal.setitimer(signal.ITIMER_REAL, 1, 1)
signal.signal(signal.SIGALRM, handle)

for _ in range(2):
    now = time.time()
    delta = 1 - (time.time() - int(time.time()))
    time.sleep(delta)
    print(now, delta, time.time())
```

If I remove the timer, then everything works as expected on 3.4.

Here is some sample output from 3.6:

```
1510913832.4726589 0.5273411273956299 1510913833.000339
received signal at 1510913833.477888
1510913833.000449 0.9995510578155518 1510913834.000187
```

And some from 3.4:

```
1510913813.525479 0.4745209217071533 1510913814.004106
received signal at 1510913814.529313
1510913814.004233 0.9957659244537354 1510913814.529413
```

----------
components: Interpreter Core
messages: 306427
nosy: Bogdan Popa
priority: normal
severity: normal
status: open
title: time.sleep(n) interrupted by signal
versions: Python 3.4

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Python tracker <report at bugs.python.org>
<https://bugs.python.org/issue32057>
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