Build fails on Python 3.14.0b1 #569
Description
orjson supports CPython 3.9, 3.10, 3.11, 3.12, 3.13, and 3.14.
Building orjson ==3.10.18 from its sdist (or from git) on Python 3.14.0b1 fails, and there are no matching cp314-cp314 wheels available on PyPI.
Python 3.14 has entered its beta stage a few days ago (2025-05-07), which means it's now feature- and ABI-locked:
https://peps.python.org/pep-0745/#schedule
orjson is a dependency of mypy[faster-cache], which is why I've encountered this issue.
$ uname -mrs
Linux 6.14.4-2-git x86_64
$ python -V
Python 3.14.0b1
$ pip install orjson
Collecting orjson
Using cached orjson-3.10.18.tar.gz (5.4 MB)
Installing build dependencies ... done
Getting requirements to build wheel ... done
Preparing metadata (pyproject.toml) ... done
Building wheels for collected packages: orjson
Building wheel for orjson (pyproject.toml) ... error
error: subprocess-exited-with-error
× Building wheel for orjson (pyproject.toml) did not run successfully.
│ exit code: 1
╰─> [79 lines of output]
Running `maturin pep517 build-wheel -i /home/basti/venv/orjson/bin/python3.14 --compatibility off`
📦 Including license file "/tmp/pip-install-5andpuvz/orjson_6952dc82b66b4376a5d1078c1a0f7360/LICENSE-APACHE"
📦 Including license file "/tmp/pip-install-5andpuvz/orjson_6952dc82b66b4376a5d1078c1a0f7360/LICENSE-MIT"
🍹 Building a mixed python/rust project
🔗 Found pyo3-ffi bindings
🐍 Found CPython 3.14 at /home/basti/venv/orjson/bin/python3.14
Compiling target-lexicon v0.13.2
Compiling proc-macro2 v1.0.95
Compiling unicode-ident v1.0.18
Compiling once_cell v1.21.3
Compiling rustversion v1.0.20
Compiling serde v1.0.219
Compiling cfg-if v1.0.0
Compiling shlex v1.3.0
Compiling libc v0.2.172
Compiling ryu v1.0.20
Compiling itoa v1.0.15
Compiling version_check v0.9.5
Compiling serde_json v1.0.140
Compiling static_assertions v1.1.0
Compiling memchr v2.7.4
Compiling itoap v1.0.1
Compiling smallvec v1.15.0
Compiling associative-cache v2.0.0
Compiling xxhash-rust v0.8.15
Compiling bytecount v0.6.8
Compiling jiff v0.2.10
Compiling simdutf8 v0.1.5
Compiling uuid v1.16.0
Compiling encoding_rs v0.8.35
Compiling half v2.6.0
Compiling cc v1.2.20
Compiling castaway v0.2.3
Compiling pyo3-build-config v0.23.3 (/tmp/pip-install-5andpuvz/orjson_6952dc82b66b4376a5d1078c1a0f7360/include/pyo3/pyo3-build-config)
Compiling quote v1.0.40
Compiling syn v2.0.101
Compiling pyo3-ffi v0.23.3 (/tmp/pip-install-5andpuvz/orjson_6952dc82b66b4376a5d1078c1a0f7360/include/pyo3/pyo3-ffi)
Compiling orjson v3.10.18 (/tmp/pip-install-5andpuvz/orjson_6952dc82b66b4376a5d1078c1a0f7360)
error: failed to run custom build command for `pyo3-ffi v0.23.3 (/tmp/pip-install-5andpuvz/orjson_6952dc82b66b4376a5d1078c1a0f7360/include/pyo3/pyo3-ffi)`
Caused by:
process didn't exit successfully: `/tmp/pip-install-5andpuvz/orjson_6952dc82b66b4376a5d1078c1a0f7360/target/release/build/pyo3-ffi-08e5cb51b71bd02e/build-script-build` (exit status: 1)
--- stdout
cargo:rustc-check-cfg=cfg(Py_LIMITED_API)
cargo:rustc-check-cfg=cfg(Py_GIL_DISABLED)
cargo:rustc-check-cfg=cfg(PyPy)
cargo:rustc-check-cfg=cfg(GraalPy)
cargo:rustc-check-cfg=cfg(py_sys_config, values("Py_DEBUG", "Py_REF_DEBUG", "Py_TRACE_REFS", "COUNT_ALLOCS"))
cargo:rustc-check-cfg=cfg(invalid_from_utf8_lint)
cargo:rustc-check-cfg=cfg(pyo3_disable_reference_pool)
cargo:rustc-check-cfg=cfg(pyo3_leak_on_drop_without_reference_pool)
cargo:rustc-check-cfg=cfg(diagnostic_namespace)
cargo:rustc-check-cfg=cfg(c_str_lit)
cargo:rustc-check-cfg=cfg(rustc_has_once_lock)
cargo:rustc-check-cfg=cfg(io_error_more)
cargo:rustc-check-cfg=cfg(fn_ptr_eq)
cargo:rustc-check-cfg=cfg(Py_3_7)
cargo:rustc-check-cfg=cfg(Py_3_8)
cargo:rustc-check-cfg=cfg(Py_3_9)
cargo:rustc-check-cfg=cfg(Py_3_10)
cargo:rustc-check-cfg=cfg(Py_3_11)
cargo:rustc-check-cfg=cfg(Py_3_12)
cargo:rustc-check-cfg=cfg(Py_3_13)
cargo:rerun-if-env-changed=PYO3_CROSS
cargo:rerun-if-env-changed=PYO3_CROSS_LIB_DIR
cargo:rerun-if-env-changed=PYO3_CROSS_PYTHON_VERSION
cargo:rerun-if-env-changed=PYO3_CROSS_PYTHON_IMPLEMENTATION
cargo:rerun-if-env-changed=PYO3_PRINT_CONFIG
cargo:rerun-if-env-changed=PYO3_USE_ABI3_FORWARD_COMPATIBILITY
--- stderr
error: the configured Python interpreter version (3.14) is newer than PyO3's maximum supported version (3.13)
= help: please check if an updated version of PyO3 is available. Current version: 0.23.3
= 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 PYO3_ENVIRONMENT_SIGNATURE="cpython-3.14-64bit" PYO3_PYTHON="/home/basti/venv/orjson/bin/python3.14" PYTHON_SYS_EXECUTABLE="/home/basti/venv/orjson/bin/python3.14" "cargo" "rustc" "--message-format" "json-render-diagnostics" "--manifest-path" "/tmp/pip-install-5andpuvz/orjson_6952dc82b66b4376a5d1078c1a0f7360/Cargo.toml" "--release" "--lib"`
Error: command ['maturin', 'pep517', 'build-wheel', '-i', '/home/basti/venv/orjson/bin/python3.14', '--compatibility', 'off'] returned non-zero exit status 1
[end of output]
note: This error originates from a subprocess, and is likely not a problem with pip.
ERROR: Failed building wheel for orjson
Failed to build orjson
ERROR: Failed to build installable wheels for some pyproject.toml based projects (orjson)
error: failed to run custom build command for `pyo3-ffi v0.23.3 (/tmp/pip-install-5andpuvz/orjson_6952dc82b66b4376a5d1078c1a0f7360/include/pyo3/pyo3-ffi)` error: the configured Python interpreter version (3.14) is newer than PyO3's maximum supported version (3.13)
The issue comes from the vendored pyo3-ffi ==0.23.3 dependency:
https://github.com/ijl/orjson/blob/3.10.18/include/pyo3/pyo3-ffi/Cargo.toml
Building with the PYO3_USE_ABI3_FORWARD_COMPATIBILITY=1 env var set also fails:
...
error[E0412]: cannot find type `c_void` in this scope
--> include/pyo3/pyo3-ffi/src/pyhash.rs:19:38
|
19 | pub fn Py_HashBuffer(ptr: *const c_void, len: Py_ssize_t) -> Py_hash_t;
| ^^^^^^ not found in this scope
|
help: consider importing one of these items
|
8 + use std::ffi::c_void;
|
8 + use std::os::raw::c_void;
|
8 + use core::ffi::c_void;
|
8 + use libc::c_void;
|
error[E0412]: cannot find type `Py_ssize_t` in this scope
--> include/pyo3/pyo3-ffi/src/pyhash.rs:19:51
|
19 | pub fn Py_HashBuffer(ptr: *const c_void, len: Py_ssize_t) -> Py_hash_t;
| ^^^^^^^^^^ not found in this scope
|
help: consider importing this type alias through its public re-export
|
8 + use crate::Py_ssize_t;
|
error[E0412]: cannot find type `Py_hash_t` in this scope
--> include/pyo3/pyo3-ffi/src/pyhash.rs:19:66
|
19 | pub fn Py_HashBuffer(ptr: *const c_void, len: Py_ssize_t) -> Py_hash_t;
| ^^^^^^^^^ not found in this scope
|
help: consider importing this type alias through its public re-export
|
8 + use crate::Py_hash_t;
|
For more information about this error, try `rustc --explain E0412`.
error: could not compile `pyo3-ffi` (lib) due to 3 previous errors
...
Here's the upstream issue for 0.25 which intends to add support for Python 3.14:
PyO3/pyo3#5107
Thanks!