Python 3.14.0rc1 seems to break (ALL?) sample code with KeyError: '__annotations__' runtime Exception?

[cljponies]

Describe the bug

I recently used Python Install Manager to install Python on a new system since that is apparently now the recommended procedure. It decided to install "Python 3.14.0rc1 (tags/v3.14.0rc1:48f8831, Jul 22 2025, 17:09:57) [MSC v.1944 64 bit (AMD64)] on win32" which I didn't think too much about (but looking at the Python docs now that is "the pre-release of the next version of the Python programming language").

I tried to run the simplest example code inside a PyCharm 2025.1.3.1 project and was confused/shocked when I hit the following exception:

(.venv) C:\Projects\APITest>python main.py
Traceback (most recent call last):
  File "C:\Projects\APITest\main.py", line 2, in <module>
    from polygon import RESTClient
  File "C:\Projects\APITest\.venv\Lib\site-packages\polygon\__init__.py", line 1, in <module>
    from .rest import RESTClient
  File "C:\Projects\APITest\.venv\Lib\site-packages\polygon\rest\__init__.py", line 1, in <module>
    from .aggs import AggsClient
  File "C:\Projects\APITest\.venv\Lib\site-packages\polygon\rest\aggs.py", line 1, in <module>
    from .base import BaseClient
  File "C:\Projects\APITest\.venv\Lib\site-packages\polygon\rest\base.py", line 10, in <module>
    from .models.request import RequestOptionBuilder
  File "C:\Projects\APITest\.venv\Lib\site-packages\polygon\rest\models\__init__.py", line 1, in <module>
    from .aggs import *
  File "C:\Projects\APITest\.venv\Lib\site-packages\polygon\rest\models\aggs.py", line 5, in <module>
    @modelclass
     ^^^^^^^^^^
  File "C:\Projects\APITest\.venv\Lib\site-packages\polygon\modelclass.py", line 13, in modelclass
    for a in cls.__dict__["__annotations__"].keys()
             ~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^
KeyError: '__annotations__'

Putting a breakpoint before that and evaluating in the Debugger console yielded:

>>> '__annotations__' in cls.__dict__
False
>>> cls
<class 'polygon.rest.models.aggs.Agg'>

Mystified that such an obvious error would go uncorrected in such a widely used repo, I looked at the Python Docs What's New and saw "The biggest changes to the implementation include template strings (PEP 750), deferred evaluation of annotations (PEP 649), and a new type of interpreter that uses tail calls." and said Aha!

Clearly PEP 649 and 749: deferred evaluation of annotations breaks your code.

Not only that but you don't even seem to be following the old Annotations Best Practices which would have avoided this error I think (but I don't claim to understand all the ins and outs of Annotations in Python).

Anyway I changed my .venv/Lib/site-packages/polygon/modelclass.py from

   def modelclass(cls: typing.Type[_T]) -> typing.Type[_T]:
       cls = dataclass(cls)
       attributes = [
           a
           for a in cls.__dict__["__annotations__"].keys()
           if not a.startswith("__") and not inspect.isroutine(a)
       ]

to:

   def modelclass(cls: typing.Type[_T]) -> typing.Type[_T]:
       cls = dataclass(cls)
       if isinstance(cls, type):
           ann = cls.__dict__.get('__annotations__', None)
       else:
           ann = getattr(cls, '__annotations__', None)
       if ann is None:
           attributes = []
       else:
           attributes = [
               a
               for a in ann.keys()
               if not a.startswith("__") and not inspect.isroutine(a)
               ]

and very limited testing indicates things seem to work now (although rate limiting makes it a bit harder to be sure).

To Reproduce
Install Python 3.14.0rc1
Run any sample code (but I used basically the first part of the README) using that version of Python.
Anything with the line:
from polygon import RESTClient
will throw a KeyError Exception.

Expected behavior
example runs without throwing KeyError Exception.

[justinpolygon]

Hi @cljponies, thanks for the heads up and suggested fix. I'll take a look.