Most changes to Python require a NEWS entry.

Please add it using the blurb_it web app or the blurb command-line tool.

All commit authors signed the Contributor License Agreement.

As mentioned on issue, DictProxy and maybe others need updating.

As mentioned on issue, DictProxy and maybe others need updating.

Added a few more bits to DictProxy to support the cases you mentioned, including fromkeys, d | {}, {} | d, reversed(d).

After your comments, I'm tempted to replace BaseListProxy with ListProxy but would like to hear back from @benjaminp if @benjaminp remembers why BaseListProxy was defined separately.

As an update, I did try removing BaseListProxy and just adding __iadd__ and __imul__ directly to ListProxy and it didn't work. I'm not sure why. Here is the code that I used to test this functionality manually.

from multiprocessing import Manager, Process

def f(x):
    x += [1]
    x *= 2
    print(x)

def g(d):
    d |= {'b': 2}
    print(d)

with Manager() as manager:

    x = manager.list()
    x.append(0)
    p = Process(target=f, args=(x,))
    p.start()
    p.join()
    q = Process(target=print, args=(x,))
    q.start()
    q.join()

    d = manager.dict()
    d['a'] = 1
    p = Process(target=g, args=(d,))
    p.start()
    p.join()
    q = Process(target=print, args=(d,))
    q.start()
    q.join()

RESULTS

ACTUAL after replacing BaseListProxy with ListProxy (the __imul__ doesn't seem to work).
ACTUAL when DictProxy is missing __ior__

[0, 1, 0, 1]
[0, 1]
{'a': 1, 'b': 2}
{'a': 1}

EXPECTED and ACTUAL with current commits for this pull request -- works with this pull request

[0, 1, 0, 1]
[0, 1, 0, 1]
{'a': 1, 'b': 2}
{'a': 1, 'b': 2}

The pull request passes the above manual test.

We could write a test that uses a process to modify a manager.list or manager.list, then check that the list or dict has actually been modified.

I found the multiprocessing tests here
https://github.com/python/cpython/blob/main/Lib/test/_test_multiprocessing.py#L5703

will try to add tests over the weekend

This pull request is ready for review. Thanks to @arhadthedev for accepting this issue, @terryjreedy for the suggestions and @sunmy2019 for the very important hints.

This minor enhancement backports recently added list and dictionary functionality into multiprocessing.managers.ListProxy and multiprocessing.managers.DictProxy so that scripts that use multiprocessing.Manager can use the same list and dictionary functionality. Would it be possible for someone to review these proposed enhancements?

@kumaraditya303
@serhiy-storchaka
@pablogsal
@iritkatriel
@gvanrossum

It's been almost a year, but I finally got around to making the changes requested by @serhiy-storchaka.

Would it be possible for someone to review these changes?
@pablogsal
@iritkatriel
@gvanrossum
@kumaraditya303

Thanks to @encukou for taking the time to review this during the PyCon 2024 sprints!!