[New-bugs-announce] [issue37208] Weird exception behaviour in ProcessPoolExecutor

[Iceflower]

New submission from Iceflower <iceflower at gmx.de>:

I don't really know where this belongs, but it is at least for me not an expected behaviour. It is weird for me at all. Please take a look if this is an intended behaviour and why it is like that.

Tested with py3.7.3, py3.8.0b1
```
A process in the process pool was terminated abruptly while the future was running or pending.
```

Tested with py 3.6.8:
```
Exception in thread Thread-1:
Traceback (most recent call last):
  File "C:\Python36\lib\threading.py", line 916, in _bootstrap_inner
    self.run()
  File "C:\Python36\lib\threading.py", line 864, in run
    self._target(*self._args, **self._kwargs)
  File "C:\Python36\lib\concurrent\futures\process.py", line 272, in _queue_management_worker
    result_item = reader.recv()
  File "C:\Python36\lib\multiprocessing\connection.py", line 251, in recv
    return _ForkingPickler.loads(buf.getbuffer())
TypeError: __init__() missing 1 required positional argument: 'num'
```

I expect that the PoolBreaker exception would work too.

Code to test:
As attachment.

----------
components: Interpreter Core
files: ProcPoolEx-exception.py
messages: 345079
nosy: Iceflower
priority: normal
severity: normal
status: open
title: Weird exception behaviour in ProcessPoolExecutor
type: behavior
versions: Python 3.8
Added file: https://bugs.python.org/file48407/ProcPoolEx-exception.py

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Python tracker <report at bugs.python.org>
<https://bugs.python.org/issue37208>
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