Pip ParsedRequirement are now frozen and can't be pickled.

[nraynaud]

Description

Pip's requirements.txt parser now returns frozen dataclasses that can't be sent through the multiprocess pickler. I enclosed the error message.

here is the line in pip's source code, it seems to have changed 4 months ago:
https://github.com/pypa/pip/blame/a84b9650a1386e1eb6edef5db0aa7addf2fc2c0c/src/pip/_internal/req/req_file.py#L105

Screenshot

No response

Console errors

$ ./venv/bin/pipupgrade -j1 --requirements requirements.txt 
Checking...
Process SpawnProcess-2:1:
Traceback (most recent call last):
  File "/usr/local/Cellar/python@3.10/3.10.16/Frameworks/Python.framework/Versions/3.10/lib/python3.10/multiprocessing/process.py", line 314, in _bootstrap
    self.run()
  File "/usr/local/Cellar/python@3.10/3.10.16/Frameworks/Python.framework/Versions/3.10/lib/python3.10/multiprocessing/process.py", line 108, in run
    self._target(*self._args, **self._kwargs)
  File "/usr/local/Cellar/python@3.10/3.10.16/Frameworks/Python.framework/Versions/3.10/lib/python3.10/concurrent/futures/process.py", line 240, in _process_worker
    call_item = call_queue.get(block=True)
  File "/usr/local/Cellar/python@3.10/3.10.16/Frameworks/Python.framework/Versions/3.10/lib/python3.10/multiprocessing/queues.py", line 122, in get
    return _ForkingPickler.loads(res)
  File "<string>", line 4, in __setattr__
dataclasses.FrozenInstanceError: cannot assign to field 'requirement'

concurrent.futures.process._RemoteTraceback: 
"""
Traceback (most recent call last):
  File "/usr/local/Cellar/python@3.10/3.10.16/Frameworks/Python.framework/Versions/3.10/lib/python3.10/concurrent/futures/process.py", line 246, in _process_worker
    r = call_item.fn(*call_item.args, **call_item.kwargs)
  File "/usr/local/Cellar/python@3.10/3.10.16/Frameworks/Python.framework/Versions/3.10/lib/python3.10/concurrent/futures/process.py", line 205, in _process_chunk
    return [fn(*args) for args in chunk]
  File "/usr/local/Cellar/python@3.10/3.10.16/Frameworks/Python.framework/Versions/3.10/lib/python3.10/concurrent/futures/process.py", line 205, in <listcomp>
    return [fn(*args) for args in chunk]
  File "/Users/nraynaud/dev/history-group-refactored-programs/venv/lib/python3.10/site-packages/pipupgrade/commands/helper.py", line 359, in get_registry_from_requirements
    registry = Registry(source = path, packages = packages, sync = sync,
  File "/Users/nraynaud/dev/history-group-refactored-programs/venv/lib/python3.10/site-packages/pipupgrade/model/registry.py", line 119, in __init__
    for package in pool.imap_unordered(partial(Package, **args), packages):
  File "/usr/local/Cellar/python@3.10/3.10.16/Frameworks/Python.framework/Versions/3.10/lib/python3.10/concurrent/futures/process.py", line 575, in _chain_from_iterable_of_lists
    for element in iterable:
  File "/usr/local/Cellar/python@3.10/3.10.16/Frameworks/Python.framework/Versions/3.10/lib/python3.10/concurrent/futures/_base.py", line 621, in result_iterator
    yield _result_or_cancel(fs.pop())
  File "/usr/local/Cellar/python@3.10/3.10.16/Frameworks/Python.framework/Versions/3.10/lib/python3.10/concurrent/futures/_base.py", line 319, in _result_or_cancel
    return fut.result(timeout)
  File "/usr/local/Cellar/python@3.10/3.10.16/Frameworks/Python.framework/Versions/3.10/lib/python3.10/concurrent/futures/_base.py", line 458, in result
    return self.__get_result()
  File "/usr/local/Cellar/python@3.10/3.10.16/Frameworks/Python.framework/Versions/3.10/lib/python3.10/concurrent/futures/_base.py", line 403, in __get_result
    raise self._exception
concurrent.futures.process.BrokenProcessPool: A process in the process pool was terminated abruptly while the future was running or pending.
"""

The above exception was the direct cause of the following exception:

Traceback (most recent call last):
  File "/Users/nraynaud/dev/history-group-refactored-programs/venv/lib/python3.10/site-packages/pipupgrade/commands/__init__.py", line 79, in command
    return _command(**ARGUMENTS)
  File "/Users/nraynaud/dev/history-group-refactored-programs/venv/lib/python3.10/site-packages/pipupgrade/commands/__init__.py", line 237, in _command
    registries    += results
  File "/usr/local/Cellar/python@3.10/3.10.16/Frameworks/Python.framework/Versions/3.10/lib/python3.10/concurrent/futures/process.py", line 575, in _chain_from_iterable_of_lists
    for element in iterable:
  File "/usr/local/Cellar/python@3.10/3.10.16/Frameworks/Python.framework/Versions/3.10/lib/python3.10/concurrent/futures/_base.py", line 621, in result_iterator
    yield _result_or_cancel(fs.pop())
  File "/usr/local/Cellar/python@3.10/3.10.16/Frameworks/Python.framework/Versions/3.10/lib/python3.10/concurrent/futures/_base.py", line 319, in _result_or_cancel
    return fut.result(timeout)
  File "/usr/local/Cellar/python@3.10/3.10.16/Frameworks/Python.framework/Versions/3.10/lib/python3.10/concurrent/futures/_base.py", line 458, in result
    return self.__get_result()
  File "/usr/local/Cellar/python@3.10/3.10.16/Frameworks/Python.framework/Versions/3.10/lib/python3.10/concurrent/futures/_base.py", line 403, in __get_result
    raise self._exception
concurrent.futures.process.BrokenProcessPool: A process in the process pool was terminated abruptly while the future was running or pending.

An error occured while performing the above command. This could be an issue with
"pipupgrade". Kindly post an issue at https://github.com/achillesrasquinha/pipupgrade/issues

[nraynaud]

I also submited the idea of letting dataclasses be pickled in pip, but they have 900 issues in their tracker, so I wouldn't hold my breath:

pypa/pip#13325