TypeError in python 3.13

[FFroehlich]

The following import

from pint import UnitRegistry

fails under python 3.13 with error message

File ".../venv/lib/python3.13/site-packages/pint/__init__.py", line 18, in <module>
    from .delegates.formatter._format_helpers import formatter
  File ".../venv/lib/python3.13/site-packages/pint/delegates/__init__.py", line 12, in <module>
    from . import txt_defparser
  File ".../venv/lib/python3.13/site-packages/pint/delegates/txt_defparser/__init__.py", line 12, in <module>
    from .defparser import DefParser
  File ".../venv/lib/python3.13/site-packages/pint/delegates/txt_defparser/defparser.py", line 10, in <module>
    from . import block, common, context, defaults, group, plain, system
  File ".../venv/lib/python3.13/site-packages/pint/delegates/txt_defparser/common.py", line 23, in <module>
    @dataclass(frozen=True)
     ~~~~~~~~~^^^^^^^^^^^^^
  File "/opt/homebrew/Cellar/[email protected]/3.13.0_1/Frameworks/Python.framework/Versions/3.13/lib/python3.13/dataclasses.py", line 1295, in wrap
    return _process_class(cls, init, repr, eq, order, unsafe_hash,
                          frozen, match_args, kw_only, slots,
                          weakref_slot)
  File "/opt/homebrew/Cellar/[email protected]/3.13.0_1/Frameworks/Python.framework/Versions/3.13/lib/python3.13/dataclasses.py", line 1043, in _process_class
    raise TypeError('cannot inherit frozen dataclass from a '
                    'non-frozen one')
TypeError: cannot inherit frozen dataclass from a non-frozen one

[hgrecco]

I will be relasing a new version tomorrow

[nhoover]

Great, thanks for fixing. I'm having the same issue.

[amit-chen-ecoplant]

Is the new version out yet?
I'm still getting the same error
E TypeError: cannot inherit frozen dataclass from a non-frozen one

[nhoover]

@hgrecco any progress? Thanks

[jmtts]

We now also see this showing up on a fresh environment Python 3.12.5.

For anyone that needs a quick workaround: you can pin the flexparser to 0.3.1 (they released the 0.4 version about 9 hours ago).

Potentially linked to this issue: hgrecco/flexparser#12

$ pyenv virtualenv 3.12 pint-test
$ pyenv activate pint-test
$ python -m pip install pint
$ python -c "import pint"
Traceback (most recent call last):
  File "<string>", line 1, in <module>
  File "/<path>/lib/python3.12/site-packages/pint/__init__.py", line 18, in <module>
    from .delegates.formatter._format_helpers import formatter
  File "/<path>/lib/python3.12/site-packages/pint/delegates/__init__.py", line 12, in <module>
    from . import txt_defparser
  File "/<path>/lib/python3.12/site-packages/pint/delegates/txt_defparser/__init__.py", line 12, in <module>
    from .defparser import DefParser
  File "/<path>/lib/python3.12/site-packages/pint/delegates/txt_defparser/defparser.py", line 10, in <module>
    from . import block, common, context, defaults, group, plain, system
  File "/<path>/lib/python3.12/site-packages/pint/delegates/txt_defparser/common.py", line 23, in <module>
    @dataclass(frozen=True)
     ^^^^^^^^^^^^^^^^^^^^^^
  File "/home/xxx/.pyenv/versions/3.12.5/lib/python3.12/dataclasses.py", line 1265, in wrap
    return _process_class(cls, init, repr, eq, order, unsafe_hash,
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/xxx/.pyenv/versions/3.12.5/lib/python3.12/dataclasses.py", line 1029, in _process_class
    raise TypeError('cannot inherit frozen dataclass from a '
TypeError: cannot inherit frozen dataclass from a non-frozen one

[nhoover]

Using 0.24.4 it's now working for me with python 3.13.0