ValueError: cannot find context for 'fork' & cannot pickle '_io.TextIOWrapper' object

[Harry1035]

In the windows environment, the following problems occur when extracting the WIKI corpus:

INFO: Starting page extraction from zhwiki-20240301-pages-articles-multistream.xml.bz2.
Traceback (most recent call last):
  File "D:\ProgramData\anaconda3\envs\myenv\lib\runpy.py", line 196, in _run_module_as_main
    return _run_code(code, main_globals, None,
  File "D:\ProgramData\anaconda3\envs\myenv\lib\runpy.py", line 86, in _run_code
    exec(code, run_globals)
  File "D:\ProgramData\anaconda3\envs\myenv\lib\site-packages\wikiextractor\WikiExtractor.py", line 643, in <module>
    main()
  File "D:\ProgramData\anaconda3\envs\myenv\lib\site-packages\wikiextractor\WikiExtractor.py", line 639, in main
    process_dump(input_file, args.templates, output_path, file_size,
  File "D:\ProgramData\anaconda3\envs\myenv\lib\site-packages\wikiextractor\WikiExtractor.py", line 417, in process_dump
    Process = get_context("fork").Process
  File "D:\ProgramData\anaconda3\envs\myenv\lib\multiprocessing\context.py", line 243, in get_context
    return super().get_context(method)
  File "D:\ProgramData\anaconda3\envs\myenv\lib\multiprocessing\context.py", line 193, in get_context
    raise ValueError('cannot find context for %r' % method) from None
ValueError: cannot find context for 'fork'

dit: wikiextractor\WikiExtractor.py line 417

Process = get_context("fork").Process
->
Process = get_context("spawn").Process

A new problem arises:

INFO: Starting page extraction from zhwiki-20240301-pages-articles-multistream.xml.bz2.
Traceback (most recent call last):
  File "D:\ProgramData\anaconda3\envs\myenv\lib\runpy.py", line 196, in _run_module_as_main
    return _run_code(code, main_globals, None,
  File "D:\ProgramData\anaconda3\envs\myenv\lib\runpy.py", line 86, in _run_code
    exec(code, run_globals)
  File "D:\ProgramData\anaconda3\envs\myenv\Scripts\wikiextractor.exe\__main__.py", line 7, in <module>
  File "D:\ProgramData\anaconda3\envs\myenv\lib\site-packages\wikiextractor\WikiExtractor.py", line 639, in main
    process_dump(input_file, args.templates, output_path, file_size,
  File "D:\ProgramData\anaconda3\envs\myenv\lib\site-packages\wikiextractor\WikiExtractor.py", line 425, in process_dump
    reduce.start()
  File "D:\ProgramData\anaconda3\envs\myenv\lib\multiprocessing\process.py", line 121, in start
    self._popen = self._Popen(self)
  File "D:\ProgramData\anaconda3\envs\myenv\lib\multiprocessing\context.py", line 336, in _Popen
    return Popen(process_obj)
  File "D:\ProgramData\anaconda3\envs\myenv\lib\multiprocessing\popen_spawn_win32.py", line 93, in __init__
    reduction.dump(process_obj, to_child)
  File "D:\ProgramData\anaconda3\envs\myenv\lib\multiprocessing\reduction.py", line 60, in dump
    ForkingPickler(file, protocol).dump(obj)
TypeError: cannot pickle '_io.TextIOWrapper' object
Traceback (most recent call last):
  File "<string>", line 1, in <module>
  File "D:\ProgramData\anaconda3\envs\myenv\lib\multiprocessing\spawn.py", line 116, in spawn_main
    exitcode = _main(fd, parent_sentinel)
  File "D:\ProgramData\anaconda3\envs\myenv\lib\multiprocessing\spawn.py", line 126, in _main
    self = reduction.pickle.load(from_parent)
EOFError: Ran out of input

[sghyan16]

"ValueError: cannot find context for 'fork' "
I got the same problem

[dengmengjie]

Thanks for your solution about switching to "spawn" mode! I am having the same issue on windows. I tried several ways but none of them work. I guess the problem lies in reduce = Process(target=reduce_process, args=(output_queue, output)), where the file output is a non-pickable parameter.
See here.
You could try running this code in ubuntu or other linux system.