Regresion ProcessPoolExecutor when updating to python 3.14

[PabloRuizCuevas]

Usually I used loky like this:

with ProcessPoolExecutor(max_workers=workers) as executor:
    for _ in range(workers):
        executor.submit(optimize, study_name, storage_url, trials, search_f, objetive_dict)

But after updating to python 3.14 it fails, it seems that paths are being concatenated in a weird maner:

#notice path repeated

/Users/pablo.ruiz/Documents/trade/.venv/bin/python: can't open file '/Users/pablo.ruiz/Documents/trade/pytrade/backtester/core/bench.py/Users/pablo.ruiz/Documents/trade/.venv/bin/python': [Errno 20] Not a directory

To be honest I didn't dig much into the details, but I was able to find the solution with a bit of help from AI plus trial and error.

import multiprocessing
ctx = multiprocessing.get_context("spawn")
ctx.set_executable(sys.executable)  # ensure correct Python interpreter is used
      with ProcessPoolExecutor(max_workers=workers, context=ctx) as executor:
          for _ in range(workers):
              executor.submit(optimize, study_name, storage_url, trials, search_f, objetive_dict)

Seems that Python 3.14 changed the process spawning mechanism, causing the interpreter path to be joined incorrectly with the script path.

Anyway feel free to close this if it is a triviality, but i felt that updating python should not break the code, so best to report it.