Fideslang cannot be imported as a package above 3.12

[tariqajyusuf]

When trying to include Fideslang into a project, I receive an error likely originating from pydantic:

...
error: the configured Python interpreter version (3.14) is newer than PyO3's maximum supported version (3.12)
    |   = help: please check if an updated version of PyO3 is available. Current version: 0.21.1
    |   = help: set PYO3_USE_ABI3_FORWARD_COMPATIBILITY=1 to suppress this check and build anyway using the stable ABI
    | warning: build failed, waiting for other jobs to finish...
    | 💥 maturin failed
    |   Caused by: Failed to build a native library through cargo
    |   Caused by: Cargo build finished with "exit status: 101": `env -u CARGO MACOSX_DEPLOYMENT_TARGET="11.0" PYO3_BUILD_EXTENSION_MODULE="1" PYO3_ENVIRONMENT_SIGNATURE="cpython-3.14-64bit" PYO3_PYTHON="/var/folders/86/d03mtb217cj1vvlhtng6z40w0000gn/T/tmpsodtj4za/.venv/bin/python" PYTHON_SYS_EXECUTABLE="/var/folders/86/d03mtb217cj1vvlhtng6z40w0000gn/T/tmpsodtj4za/.venv/bin/python" "cargo" "rustc" "--features" "pyo3/extension-module" "--message-format" "json-render-diagnostics" "--manifest-path" "/private/var/folders/86/d03mtb217cj1vvlhtng6z40w0000gn/T/tmpawrghvvx/pydantic_core-2.18.2/Cargo.toml" "--release" "--lib" "--crate-type" "cdylib" "--" "-C" "link-arg=-undefined" "-C" "link-arg=dynamic_lookup" "-C" "link-args=-Wl,-install_name,@rpath/pydantic_core._pydantic_core.cpython-314-darwin.so"`
    | Error: command ['maturin', 'pep517', 'build-wheel', '-i', '/var/folders/86/d03mtb217cj1vvlhtng6z40w0000gn/T/tmpsodtj4za/.venv/bin/python', '--compatibility', 'off'] returned non-zero exit status 1

Upon trying to set PYO3_USE_ABI3_FORWARD_COMPATIBILITY=1 in my environment, the dependency install still fails:

error: failed to run custom build command for `pydantic-core v2.18.2 (/private/var/folders/86/d03mtb217cj1vvlhtng6z40w0000gn/T/tmpnz0nq_1k/pydantic_core-2.18.2)`
    | 
    | Caused by:
    |   process didn't exit successfully: `/private/var/folders/86/d03mtb217cj1vvlhtng6z40w0000gn/T/tmpnz0nq_1k/pydantic_core-2.18.2/target/release/build/pydantic-core-733339ca6174934f/build-script-build` (exit status: 101)
    |   --- stdout
    |   cargo:rustc-cfg=Py_3_6
    |   cargo:rustc-cfg=Py_3_7
    |   cargo:rustc-cfg=Py_3_8
    |   cargo:rustc-cfg=Py_3_9
    |   cargo:rustc-cfg=Py_3_10
    |   cargo:rustc-cfg=Py_3_11
    |   cargo:rustc-cfg=Py_3_12
    |   cargo:rustc-cfg=Py_3_13
    |   cargo:rustc-cfg=Py_3_14
    |   cargo:rustc-cfg=Py_LIMITED_API
    |   cargo:rerun-if-changed=python/pydantic_core/core_schema.py
    |   cargo:rerun-if-changed=generate_self_schema.py
    | 
    |   --- stderr
    |   Traceback (most recent call last):
    |     File "/private/var/folders/86/d03mtb217cj1vvlhtng6z40w0000gn/T/tmpnz0nq_1k/pydantic_core-2.18.2/generate_self_schema.py", line 193, in eval_forward_ref
    |       return type_._evaluate(core_schema.__dict__, None, set())
    |              ~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |   TypeError: ForwardRef._evaluate() missing 1 required keyword-only argument: 'recursive_guard'
    | 
    |   During handling of the above exception, another exception occurred:
    | 
    |   Traceback (most recent call last):
    |     File "/private/var/folders/86/d03mtb217cj1vvlhtng6z40w0000gn/T/tmpnz0nq_1k/pydantic_core-2.18.2/generate_self_schema.py", line 241, in <module>
    |       main()
    |       ~~~~^^
    |     File "/private/var/folders/86/d03mtb217cj1vvlhtng6z40w0000gn/T/tmpnz0nq_1k/pydantic_core-2.18.2/generate_self_schema.py", line 211, in main
    |       value = get_schema(s, definitions)
    |     File "/private/var/folders/86/d03mtb217cj1vvlhtng6z40w0000gn/T/tmpnz0nq_1k/pydantic_core-2.18.2/generate_self_schema.py", line 55, in get_schema
    |       return type_dict_schema(obj, definitions)
    |     File "/private/var/folders/86/d03mtb217cj1vvlhtng6z40w0000gn/T/tmpnz0nq_1k/pydantic_core-2.18.2/generate_self_schema.py", line 153, in type_dict_schema
    |       field_type = eval_forward_ref(field_type)
    |     File "/private/var/folders/86/d03mtb217cj1vvlhtng6z40w0000gn/T/tmpnz0nq_1k/pydantic_core-2.18.2/generate_self_schema.py", line 196, in eval_forward_ref
    |       return type_._evaluate(core_schema.__dict__, None)
    |              ~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |   TypeError: ForwardRef._evaluate() missing 1 required keyword-only argument: 'recursive_guard'
    | 
    |   thread 'main' panicked at build.rs:29:9:

In debugging this I also noticed that fideslang cannot be built with python versions above 3.9. I suspect these issues may be related.