3.13t free-threading compatibility

.github/workflows/artifact.yaml

@@ -40,11 +40,11 @@ jobs:
 
     - run: python3 -m pip install --user -r test/requirements.txt -r integration/requirements.txt mypy
 
-    - run: pytest -s -rxX -v -n 4 test
+    - run: pytest -v test
       env:
         PYTHONMALLOC: "debug"
 
-    - run: ./integration/run thread
+    - run: ./integration/run concurrent
     - run: ./integration/run http
     - run: ./integration/run init
     - run: ./integration/run typestubs
@@ -64,6 +64,14 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
+        python: [
+          { interpreter: 'python3.13t', package: 'python3.13-freethreading', compatibility: "manylinux_2_34" },
+          { interpreter: 'python3.13', package: 'python3.13', compatibility: "manylinux_2_17" },
+          { interpreter: 'python3.12', package: 'python3.12', compatibility: "manylinux_2_17" },
+          { interpreter: 'python3.11', package: 'python3.11', compatibility: "manylinux_2_17" },
+          { interpreter: 'python3.10', package: 'python3.10', compatibility: "manylinux_2_17" },
+          { interpreter: 'python3.9', package: 'python3.9', compatibility: "manylinux_2_17" },
+        ]
         arch: [
           {
             cc: "clang",
@@ -75,13 +83,6 @@ jobs:
             target: "x86_64-unknown-linux-gnu",
           },
         ]
-        python: [
-          { interpreter: 'python3.13', package: 'python3.13', compatibility: "manylinux_2_17" },
-          { interpreter: 'python3.12', package: 'python3.12', compatibility: "manylinux_2_17" },
-          { interpreter: 'python3.11', package: 'python3.11', compatibility: "manylinux_2_17" },
-          { interpreter: 'python3.10', package: 'python3.10', compatibility: "manylinux_2_17" },
-          { interpreter: 'python3.9', package: 'python3.9', compatibility: "manylinux_2_17" },
-        ]
     env:
       PYTHON: "${{ matrix.python.interpreter }}"
       PYTHON_PACKAGE: "${{ matrix.python.package }}"
@@ -125,7 +126,8 @@ jobs:
 
         ./script/install-fedora
 
-        source "${VENV}/bin/activate"
+        export ORJSON_ENABLE_FREETHREADING="$(script/is_freethreading)"
+        if [[ $ORJSON_ENABLE_FREETHREADING -eq 1 ]]; then export PYTHON_GIL=0; fi
 
         maturin build --release --strip \
           --features="${FEATURES}" \
@@ -135,8 +137,8 @@ jobs:
 
         uv pip install ${CARGO_TARGET_DIR}/wheels/orjson*.whl
 
-        pytest -s -rxX -v -n 4 test
-        ./integration/run thread
+        pytest -v test
+        ./integration/run concurrent
         ./integration/run http
         ./integration/run init
 
@@ -158,6 +160,10 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
+        python: [
+          { interpreter: 'python3.13t', package: 'python3.13-freethreading', compatibility: "manylinux_2_34" },
+          { interpreter: 'python3.13', package: 'python3.13', compatibility: "manylinux_2_17" },
+        ]
         arch: [
           {
             cc: "clang",
@@ -169,9 +175,6 @@ jobs:
             target: "aarch64-unknown-linux-gnu",
           },
         ]
-        python: [
-          { interpreter: 'python3.13', package: 'python3.13', compatibility: "manylinux_2_17" },
-        ]
     env:
       PYTHON: "${{ matrix.python.interpreter }}"
       PYTHON_PACKAGE: "${{ matrix.python.package }}"
@@ -214,8 +217,8 @@ jobs:
 
         ./script/install-fedora
 
-        source "${HOME}/.cargo/env"
-        source "${VENV}/bin/activate"
+        export ORJSON_ENABLE_FREETHREADING="$(script/is_freethreading)"
+        if [[ $ORJSON_ENABLE_FREETHREADING -eq 1 ]]; then export PYTHON_GIL=0; fi
 
         maturin build --release --strip \
           --features="${FEATURES}" \
@@ -225,7 +228,7 @@ jobs:
 
         uv pip install ${CARGO_TARGET_DIR}/wheels/orjson*.whl
 
-        pytest -s -rxX -v -n 2 test
+        pytest -v test
 
         cp ${CARGO_TARGET_DIR}/wheels/orjson*.whl dist
 
@@ -302,7 +305,7 @@ jobs:
           venv/bin/pip install -U pip wheel
           venv/bin/pip install -r test/requirements.txt
           venv/bin/pip install orjson --no-index --find-links dist/ --force-reinstall
-          venv/bin/python -m pytest -s -rxX -v -n 2 test
+          venv/bin/python -m pytest -v test
 
     - name: Store wheels
       if: "startsWith(github.ref, 'refs/tags/')"
@@ -441,11 +444,11 @@ jobs:
           --target=universal2-apple-darwin
         uv pip install target/wheels/orjson*.whl
 
-    - run: pytest -s -rxX -v -n 3 test
+    - run: pytest -v test
       env:
         PYTHONMALLOC: "debug"
 
-    - run: source .venv/bin/activate && ./integration/run thread
+    - run: source .venv/bin/activate && ./integration/run concurrent
     - run: source .venv/bin/activate && ./integration/run http
     - run: source .venv/bin/activate && ./integration/run init
 
@@ -510,11 +513,11 @@ jobs:
           --target=universal2-apple-darwin
         uv pip install target/wheels/orjson*.whl
 
-    - run: pytest -s -rxX -v -n 3 test
+    - run: pytest -v test
       env:
         PYTHONMALLOC: "debug"
 
-    - run: source .venv/bin/activate && ./integration/run thread
+    - run: source .venv/bin/activate && ./integration/run concurrent
     - run: source .venv/bin/activate && ./integration/run http
     - run: source .venv/bin/activate && ./integration/run init
 

.github/workflows/debug.yaml

@@ -51,7 +51,7 @@ jobs:
       env:
         PYTHONMALLOC: "debug"
 
-    - run: ./integration/run thread
+    - run: ./integration/run concurrent
       timeout-minutes: 2
 
     - run: ./integration/run http

Cargo.toml

@@ -51,6 +51,7 @@ unwind = ["unwinding"]
 yyjson = []
 
 # Features detected by build.rs. Do not specify.
+freethreading = []
 inline_int = []
 intrinsics = []
 optimize = []

README.md

@@ -41,6 +41,8 @@ and i686/x86 wheels for Windows.
 orjson does not and will not support PyPy, embedded Python builds for
 Android/iOS, or PEP 554 subinterpreters.
 
+orjson has experimental support for PEP 703 free-threading CPython.
+
 Releases follow semantic versioning and serializing a new object type
 without an opt-in flag is considered a breaking change.
 
@@ -74,9 +76,10 @@ available in the repository.
     1. [Latency](https://github.com/ijl/orjson?tab=readme-ov-file#latency)
     2. [Memory](https://github.com/ijl/orjson?tab=readme-ov-file#memory)
     3. [Reproducing](https://github.com/ijl/orjson?tab=readme-ov-file#reproducing)
-5. [Questions](https://github.com/ijl/orjson?tab=readme-ov-file#questions)
-6. [Packaging](https://github.com/ijl/orjson?tab=readme-ov-file#packaging)
-7. [License](https://github.com/ijl/orjson?tab=readme-ov-file#license)
+6. [Free-threading](https://github.com/ijl/orjson?tab=readme-ov-file#free-threading)
+7. [Questions](https://github.com/ijl/orjson?tab=readme-ov-file#questions)
+8. [Packaging](https://github.com/ijl/orjson?tab=readme-ov-file#packaging)
+9. [License](https://github.com/ijl/orjson?tab=readme-ov-file#license)
 
 ## Usage
 
@@ -161,7 +164,8 @@ serializing subclasses, specify the option `orjson.OPT_PASSTHROUGH_SUBCLASS`.
 
 The output is a `bytes` object containing UTF-8.
 
-The global interpreter lock (GIL) is held for the duration of the call.
+In non-free-threading Python, the global interpreter lock (GIL) is held for
+the duration of the call.
 
 It raises `JSONEncodeError` on an unsupported type. This exception message
 describes the invalid object with the error message
@@ -630,7 +634,8 @@ orjson maintains a cache of map keys for the duration of the process. This
 causes a net reduction in memory usage by avoiding duplicate strings. The
 keys must be at most 64 bytes to be cached and 2048 entries are stored.
 
-The global interpreter lock (GIL) is held for the duration of the call.
+In non-free-threading Python, the global interpreter lock (GIL) is held for
+the duration of the call.
 
 It raises `JSONDecodeError` if given an invalid type or invalid
 JSON. This includes if the input contains `NaN`, `Infinity`, or `-Infinity`,
@@ -1179,6 +1184,22 @@ orjson 3.10.6, ujson 5.10.0, python-rapidson 1.18, and simplejson 3.19.2.
 The latency results can be reproduced using the `pybench` and `graph`
 scripts. The memory results can be reproduced using the `pymem` script.
 
+## Free-threading
+
+orjson 3.11.0 introduces experimental support for PEP 703 free-threading CPython.
+
+orjson supports an arbitrary number of Python threads concurrently calling the
+library. There are no threads or queues internal to the library. There are
+no Python critical sections.
+
+PyPI wheels are provided for manylinux amd64 and aarch64.
+
+To build a wheel with free-threading support, see
+[packaging](https://github.com/ijl/orjson?tab=readme-ov-file#packaging).
+
+The free-threading implementation does not respect semantic versioning and may
+be removed entirely in the future.
+
 ## Questions
 
 ### Why can't I install it from PyPI?
@@ -1216,6 +1237,10 @@ It benefits from also having a C build environment to compile a faster
 deserialization backend. See this project's `manylinux_2_28` builds for an
 example using clang and LTO.
 
+Building a wheel with freethreading support requires the environmental
+variable `ORJSON_ENABLE_FREETHREADING` set during build or the
+`--features=freethreading` argument passed to maturin.
+
 The project's own CI tests against `nightly-2024-10-25` and stable 1.72. It
 is prudent to pin the nightly version because that channel can introduce
 breaking changes.

bench/requirements.txt

@@ -1,4 +1,4 @@
-memory-profiler
+memory-profiler; python_version<"3.13"
 pandas; python_version<"3.13"
 pytest-benchmark
 pytest-random-order

build.rs

@@ -11,6 +11,7 @@ fn main() {
     println!("cargo:rerun-if-env-changed=ORJSON_DISABLE_AVX512");
     println!("cargo:rerun-if-env-changed=ORJSON_DISABLE_SIMD");
     println!("cargo:rerun-if-env-changed=ORJSON_DISABLE_YYJSON");
+    println!("cargo:rerun-if-env-changed=ORJSON_ENABLE_FREETHREADING");
     println!("cargo:rerun-if-env-changed=RUSTFLAGS");
     println!("cargo:rustc-check-cfg=cfg(intrinsics)");
     println!("cargo:rustc-check-cfg=cfg(optimize)");
@@ -31,6 +32,13 @@ fn main() {
         println!("cargo:rustc-cfg=feature=\"setitem_knownhash\"");
     }
 
+    let freethreading_env = env::var("ORJSON_ENABLE_FREETHREADING");
+    if (freethreading_env.is_ok() && freethreading_env.unwrap() == "1")
+        || env::var("CARGO_FEATURE_FREETHREADING").is_ok()
+    {
+        println!("cargo:rustc-cfg=feature=\"freethreading\"");
+    }
+
     if let Some(true) = version_check::supports_feature("core_intrinsics") {
         println!("cargo:rustc-cfg=feature=\"intrinsics\"");
     }

ci/azure-win.yml

@@ -29,12 +29,12 @@ steps:
     UNSAFE_PYO3_SKIP_VERSION_CHECK: "1"
 - script: python.exe -m pip install orjson --no-index --find-links=D:\a\1\s\target\wheels
   displayName: install
-- script: python.exe -m pytest -s -rxX -v test
+- script: python.exe -m pytest -v test
   env:
     PYTHONMALLOC: "debug"
   displayName: pytest
-- script: python.exe integration\thread
-  displayName: thread
+- script: python.exe integration\concurrent
+  displayName: concurrent
 - script: python.exe integration\init
   displayName: init
 - bash: ./ci/deploy /d/a/1/s/target/wheels/*.whl