How to share fakefs between subprocesses

[AliyevH]

Hi. How to share fakefs mocked file between subprocesses? Changes made in subprocess will not be seen by main process.

For example.

# mymodule.py
config_file = 'my.config'


def change_content(data):
    with open(config_file, 'w', ) as f:
        f.write(str(data))
  

# test_mymodule.py
import mymodule
config_content = 'default content'

def test_mymodule_race_condition():
    with Patcher() as patcher:
        patcher.fs.create_file('my.config', contents=config_content)

        p = Process(target=mymodule.change_content,  args=('modified content'))
        p.start()
        p.join()

        with open(mymodule.config_file, 'r', encoding='utf-8') as f:
            print(f.read())
        # THIS WILL PRINT `default content`.

[mrbean-bremen]

Unfortuantely, this is not possible. The file system lives completely in memory, and there is currently no mechanism to share it between processes.
See also the limitations regarding subprocess.

[AliyevH]

Thanks