Incompatibility with Python 3.14

[ilovelinux]

Tested with httpcore==1.0.9

Python 3.14.0rc3 (main, Sep 18 2025, 19:47:22) [Clang 20.1.4 ] on linux
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>>> import httpcore
Traceback (most recent call last):
  File "<python-input-0>", line 1, in <module>
    import httpcore
  File "/lib/python3.14/site-packages/httpcore/__init__.py", line 140, in <module>
    setattr(__locals[__name], "__module__", "httpcore")  # noqa
    ~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
AttributeError: 'typing.Union' object has no attribute '__module__' and no __dict__ for setting new attributes. Did you mean: '__reduce__'?
>>> 

[cclauss]

Python 3.14 (the π version) was released today.

• https://www.python.org/downloads/release/python-3140/
• https://github.com/actions/python-versions/releases

[GalaxySnail]

related to:

• typing.Union does not support attribute assignment post gh-105511 python/cpython#132139

[ilovelinux]

Apparently my environment was using an older version of httpcore (1.0.7).

In fact this issue has already been fixed with #1005, released in v1.0.8.

I can confirm it works with Python 3.14rc3.

Duplicate of #995