Port for use with Python 3.13 free-threaded build?

[smontanaro]

I'm trying to build/install Jupyter with a free-threaded build of Python 3.13. The compile fails because _ffi.c (I think) uses the limited API, which isn't supported in the free-threaded build. Details about porting code for free-threading are here:

https://py-free-threading.github.io/porting/#limited-api-support

Any chance this could be worked into argon2-cffi?

      running build_ext
      generating cffi module 'build/temp.macosx-15.1-arm64-cpython-313t/_ffi.c'
      creating build/temp.macosx-15.1-arm64-cpython-313t
      building '_ffi' extension
      creating build/temp.macosx-15.1-arm64-cpython-313t/build/temp.macosx-15.1-arm64-cpython-313t
      creating build/temp.macosx-15.1-arm64-cpython-313t/extras/libargon2/src
      creating build/temp.macosx-15.1-arm64-cpython-313t/extras/libargon2/src/blake2
      clang-18 -fno-strict-overflow -Wsign-compare -Wunreachable-code -DNDEBUG -g -O3 -Wall -Iextras/libargon2/include -I/Users/skip/py3.13/include -I/Users/skip/.local/include/python3.13t -c build/temp.macosx-15.1-arm64-cpython-313t/_ffi.c -o build/temp.macosx-15.1-arm64-cpython-313t/build/temp.macosx-15.1-arm64-cpython-313t/_ffi.o
      In file included from build/temp.macosx-15.1-arm64-cpython-313t/_ffi.c:57:
      /Users/skip/.local/include/python3.13t/Python.h:51:4: error: "The limited API is not currently supported in the free-threaded build"
         51 | #  error "The limited API is not currently supported in the free-threaded build"
            |    ^
      In file included from build/temp.macosx-15.1-arm64-cpython-313t/_ffi.c:57:
      In file included from /Users/skip/.local/include/python3.13t/Python.h:72:
      /Users/skip/.local/include/python3.13t/object.h:213:5: error: unknown type name 'PyMutex'
        213 |     PyMutex ob_mutex;           // per-object lock
            |     ^
      /Users/skip/.local/include/python3.13t/object.h:320:22: error: call to undeclared function '_Py_atomic_load_uint32_relaxed'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
        320 |     uint32_t local = _Py_atomic_load_uint32_relaxed(&ob->ob_ref_local);
            |                      ^
      /Users/skip/.local/include/python3.13t/object.h:324:25: error: call to undeclared function '_Py_atomic_load_ssize_relaxed'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
        324 |     Py_ssize_t shared = _Py_atomic_load_ssize_relaxed(&ob->ob_ref_shared);
            |                         ^
      /Users/skip/.local/include/python3.13t/object.h:358:13: error: call to undeclared function '_Py_atomic_load_uint32_relaxed'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
        358 |     return (_Py_atomic_load_uint32_relaxed(&op->ob_ref_local) ==
            |             ^
      /Users/skip/.local/include/python3.13t/object.h:358:63: warning: comparison of integers of different signs: 'int' and 'unsigned int' [-Wsign-compare]
        358 |     return (_Py_atomic_load_uint32_relaxed(&op->ob_ref_local) ==
            |             ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ^
        359 |             _Py_IMMORTAL_REFCNT_LOCAL);
            |             ~~~~~~~~~~~~~~~~~~~~~~~~~
      /Users/skip/.local/include/python3.13t/object.h:396:9: error: call to undeclared function '_Py_IsOwnedByCurrentThread'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
        396 |     if (_Py_IsOwnedByCurrentThread(ob)) {
            |         ^
      /Users/skip/.local/include/python3.13t/object.h:436:5: error: call to undeclared function '_Py_atomic_store_ssize_relaxed'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
        436 |     _Py_atomic_store_ssize_relaxed(&ob->ob_size, size);
            |     ^
      /Users/skip/.local/include/python3.13t/object.h:810:22: error: call to undeclared function '_Py_atomic_load_uint32_relaxed'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
        810 |     uint32_t local = _Py_atomic_load_uint32_relaxed(&op->ob_ref_local);
            |                      ^
      /Users/skip/.local/include/python3.13t/object.h:816:9: error: call to undeclared function '_Py_IsOwnedByCurrentThread'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
        816 |     if (_Py_IsOwnedByCurrentThread(op)) {
            |         ^
      /Users/skip/.local/include/python3.13t/object.h:817:9: error: call to undeclared function '_Py_atomic_store_uint32_relaxed'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
        817 |         _Py_atomic_store_uint32_relaxed(&op->ob_ref_local, new_local);
            |         ^
      /Users/skip/.local/include/python3.13t/object.h:820:9: error: call to undeclared function '_Py_atomic_add_ssize'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
        820 |         _Py_atomic_add_ssize(&op->ob_ref_shared, (1 << _Py_REF_SHARED_SHIFT));
            |         ^
      /Users/skip/.local/include/python3.13t/object.h:904:22: error: call to undeclared function '_Py_atomic_load_uint32_relaxed'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
        904 |     uint32_t local = _Py_atomic_load_uint32_relaxed(&op->ob_ref_local);
            |                      ^
      /Users/skip/.local/include/python3.13t/object.h:909:9: error: call to undeclared function '_Py_IsOwnedByCurrentThread'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
        909 |     if (_Py_IsOwnedByCurrentThread(op)) {
            |         ^
      /Users/skip/.local/include/python3.13t/object.h:911:9: error: call to undeclared function '_Py_atomic_store_uint32_relaxed'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
        911 |         _Py_atomic_store_uint32_relaxed(&op->ob_ref_local, local);
            |         ^
      /Users/skip/.local/include/python3.13t/object.h:913:13: error: call to undeclared function '_Py_MergeZeroLocalRefcount'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
        913 |             _Py_MergeZeroLocalRefcount(op);
            |             ^
      /Users/skip/.local/include/python3.13t/object.h:917:9: error: call to undeclared function '_Py_DecRefShared'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
        917 |         _Py_DecRefShared(op);
            |         ^
      1 warning and 16 errors generated.
      error: command '/opt/homebrew/Cellar/llvm@18/18.1.8/bin/clang-18' failed with exit code 1
      [end of output]

[hynek]

please refer to hynek/argon2-cffi-bindings#67 and hynek/argon2-cffi-bindings#70

the TL;DR is that right now we’re blocked by the cffi dependency but things are in motion