Support Cython 3 (and also Python 3.13).

[J08nY]

Description

Fixes the build on Python 3.13 (with Cython 3). Fixes #926 and fixes #947.

Types of change

Removal of Cython version restriction and a small fix.

Checklist

• I confirm that I have the right to submit this contribution under the project's MIT license.
• I ran the tests, and all new and existing tests passed.
• My changes don't require a change to the documentation, or if they do, I've added all required information.

[ngoldbaum]

It would also be neat to check the Cython 3.1 alpha release or Cython's master branch against free-threaded 3.13.

See https://py-free-threading.github.io for more info about supporting free-threaded Python in native code.

[J08nY]

Any progress on getting this in and cutting a new release? Python 3.13 is now 4 months old.

[h-vetinari]

I would be willing to test this in conda-forge (where we run the test suite anyway), but thinc depends on srsly, confection & wasabi, so those need to be solved first.

Xref conda-forge/srsly-feedstock#53

[J08nY]

I would be willing to test this in conda-forge (where we run the test suite anyway), but thinc depends on srsly, confection & wasabi, so those need to be solved first.

It seems that all of srsly, confection & wasabi now install under Python 3.13. Atleast in my environment.

[J08nY]

I am getting lots of warnings while running tests under 3.13:

thinc/tests/layers/test_layers_api.py: 1594 warnings
thinc/tests/layers/test_lstm.py: 238 warnings
thinc/tests/layers/test_transforms.py: 296 warnings
thinc/tests/layers/test_with_transforms.py: 2508 warnings
thinc/tests/model/test_validation.py: 145 warnings
thinc/tests/test_config.py: 66 warnings
  /tmp/virt/lib/python3.13/site-packages/pydantic/v1/typing.py:68: DeprecationWarning: Failing to pass a value to the 'type_params' parameter of 'typing.ForwardRef._evaluate' is deprecated, as it leads to incorrect behaviour when calling typing.ForwardRef._evaluate on a stringified annotation that references a PEP 695 type parameter. It will be disallowed in Python 3.15.
    return cast(Any, type_)._evaluate(globalns, localns, recursive_guard=set())

Also some errors:

============================================================================================= short test summary info =============================================================================================
FAILED thinc/tests/backends/test_ops.py::test_ops_consistency[NumpyOps] - AssertionError: alloc
FAILED thinc/tests/layers/test_layers_api.py::test_layers_from_config[SparseLinear.v1-kwargs55-in_data55-out_data55] - NameError: name 'InT' is not defined
FAILED thinc/tests/layers/test_layers_api.py::test_layers_from_config[SparseLinear.v2-kwargs56-in_data56-out_data56] - NameError: name 'InT' is not defined
FAILED thinc/tests/layers/test_layers_api.py::test_layers_from_config[premap_ids.v1-kwargs59-in_data59-out_data59] - NameError: name 'InT' is not defined
FAILED thinc/tests/layers/test_layers_api.py::test_dropout[data2] - thinc.util.DataValidationError: 
FAILED thinc/tests/layers/test_layers_api.py::test_layers_batching_all[premap_ids.v1-kwargs59-in_data59-out_data59] - NameError: name 'InT' is not defined

which expand out to this, and are clearly connected to the warning:

thinc/tests/layers/test_layers_api.py:211: in util_batch_unbatch_array
    model.initialize(in_data, out_data)
thinc/model.py:316: in initialize
    validate_fwd_input_output(self.name, self._func, X, Y)
thinc/util.py:588: in validate_fwd_input_output
    ArgModel.update_forward_refs(**types.__dict__)
../virt/lib/python3.13/site-packages/pydantic/v1/main.py:814: in update_forward_refs
    update_model_forward_refs(cls, cls.__fields__.values(), cls.__config__.json_encoders, localns)
../virt/lib/python3.13/site-packages/pydantic/v1/typing.py:559: in update_model_forward_refs
    update_field_forward_refs(f, globalns=globalns, localns=localns)
../virt/lib/python3.13/site-packages/pydantic/v1/typing.py:525: in update_field_forward_refs
    field.type_ = evaluate_forwardref(field.type_, globalns, localns or None)
../virt/lib/python3.13/site-packages/pydantic/v1/typing.py:68: in evaluate_forwardref
    return cast(Any, type_)._evaluate(globalns, localns, recursive_guard=set())
/usr/lib/python3.13/typing.py:1081: in _evaluate
    eval(self.__forward_code__, globalns, localns),

Seems to be an upstream pydantic issue: pydantic/pydantic#9613