AssertionError: daemonic processes are not allowed to have children

[ana-jiangR]

bulk download failure occurred when setting "threads=True" default

see my code below:
def test_yfc_download():
tickers = ["INTC", "MSFT"]

  df = yfc.download(tickers, 
              interval='1h', 
              period=TIME_PERIOD_60M, 
              max_age='4h', 
              group_by='ticker', 
              # threads=False
              )


  print(df['MSFT'][['High', 'Low', 'Close', 'Volume']])

  return

if __name__ == '__main__':

  import yfinance_cache as yfc

  TIME_PERIOD_60M = '250d'
  test_yfc_download()`

The failure log is as below:

Process SpawnPoolWorker-3:
Traceback (most recent call last):
File "C:\miniconda3\envs\yfinance\lib\multiprocessing\process.py", line 315, in _bootstrap
self.run()
Traceback (most recent call last):
File "C:\miniconda3\envs\yfinance\lib\multiprocessing\process.py", line 108, in run
self._target(*self._args, **self._kwargs)
File "C:\miniconda3\envs\yfinance\lib\multiprocessing\process.py", line 315, in _bootstrap
self.run()
File "C:\miniconda3\envs\yfinance\lib\multiprocessing\process.py", line 108, in run
self._target(*self._args, **self._kwargs)
File "C:\miniconda3\envs\yfinance\lib\multiprocessing\pool.py", line 114, in worker
task = get()
File "C:\miniconda3\envs\yfinance\lib\multiprocessing\pool.py", line 114, in worker
task = get()
File "C:\miniconda3\envs\yfinance\lib\multiprocessing\queues.py", line 367, in get
return ForkingPickler.loads(res)
File "C:\miniconda3\envs\yfinance\lib\multiprocessing\queues.py", line 367, in get
return ForkingPickler.loads(res)
File "C:\miniconda3\envs\yfinance\lib\site-packages\yfinance_cache_init.py", line 4, in
from .yfc_ticker import Ticker, verify_cached_tickers_prices
File "C:\miniconda3\envs\yfinance\lib\site-packages\yfinance_cache_init.py", line 4, in
from .yfc_ticker import Ticker, verify_cached_tickers_prices
File "C:\miniconda3\envs\yfinance\lib\site-packages\yfinance_cache\yfc_ticker.py", line 7, in
from . import yfc_time as yfct
File "C:\miniconda3\envs\yfinance\lib\site-packages\yfinance_cache\yfc_ticker.py", line 7, in
from . import yfc_time as yfct
File "C:\miniconda3\envs\yfinance\lib\site-packages\yfinance_cache\yfc_time.py", line 22, in
manager = Manager()
File "C:\miniconda3\envs\yfinance\lib\multiprocessing\context.py", line 57, in Manager
m.start()
File "C:\miniconda3\envs\yfinance\lib\multiprocessing\managers.py", line 554, in start
self._process.start()
File "C:\miniconda3\envs\yfinance\lib\multiprocessing\process.py", line 118, in start assert not _current_process._config.get('daemon'),
File "C:\miniconda3\envs\yfinance\lib\site-packages\yfinance_cache\yfc_time.py", line 22, in
manager = Manager()
File "C:\miniconda3\envs\yfinance\lib\multiprocessing\context.py", line 57, in Manager
m.start()
AssertionError: daemonic processes are not allowed to have children
File "C:\miniconda3\envs\yfinance\lib\multiprocessing\managers.py", line 554, in start
self._process.start()
File "C:\miniconda3\envs\yfinance\lib\multiprocessing\process.py", line 118, in start assert not _current_process._config.get('daemon'),
AssertionError: daemonic processes are not allowed to have children

I'm using Window 11 OS.

my Python version:
Python 3.9.18 (main, Sep 11 2023, 14:09:26) [MSC v.1916 64 bit (AMD64)] on win32

see dependences' version:
yfance_cache (0.4.7)
yfance (0.2.31)
pandas (2.1.1)
exchange-calendars (4.5)
scipy (1.10.1)
click (8.1.7)
numpy (1.26.0)
pyluach (2.2.0)
python-dateutil (2.8.2)
toolz (0.12.0)
tzdata (2023.3)
korean-lunar-calendar (0.3.1)
pytz (2023.3.post1)
requests (2.31.0)
multitaskg(0.0.11)
lxml (4.9.3)
appdirs (1.4.4)
frozendict(2.3.8)
peewee (3.16.3)
beautifulsoup4 (4.12.2)
html5lib (1.1)
colorama (0.4.4)
soupsieve>1.2 (2.5)
six>=1.9 (1.16.0)
webencodgs (0.5.1)
charset-normalizer (3.3.0)
idna(3.4)
urllib3 (1.26.17)
certifi (2023.7.22)

[ValueRaider]

I never had the chance to test on Windows. Turns out multiprocessing behaves differently. I think I found fix but will need you to test.

[ana-jiangR]

Great, thank you. let me know how to test that when your patch is ready.

[ana-jiangR]

Moving discussion to pull request.

[ValueRaider]

Moving discussion to pull request.