docs: Describe arbitrary_precision feature in readme. Update changelog. ci: Run tests for arbitrary_precision feature.

Author: jpmckinney

.github/workflows/ci.yml

@@ -94,6 +94,9 @@ jobs:
       - name: Test (abi3)
         run: cargo test --verbose --features pyo3/abi3-py37
 
+      - name: Test (arbitrary_precision)
+        run: cargo test --verbose --features arbitrary_precision
+
     env:
       RUST_BACKTRACE: 1
 

CHANGELOG.md

@@ -1,3 +1,6 @@
+## 0.28.0 - 2026-02-17
+- Add `arbitrary_precision` feature
+
 ## 0.27.0 - 2025-11-07
 - Update to PyO3 0.27
 

README.md

@@ -17,7 +17,7 @@ Pythonize has two main public APIs: `pythonize` and `depythonize`.
 [Serde]: https://github.com/serde-rs/serde
 [PyO3]: https://github.com/PyO3/pyo3
 
-# Examples
+## Examples
 
 ```rust
 use serde::{Serialize, Deserialize};
@@ -47,3 +47,14 @@ Python::attach(|py| {
     assert_eq!(new_sample, sample);
 })
 ```
+
+## Features
+
+### `arbitrary_precision`
+
+Enable support for `serde_json`'s `arbitrary_precision` feature, which allows handling numbers that exceed the range of `i128`/`u128` when converting `serde_json::Value` to and from Python.
+
+```toml
+[dependencies]
+pythonize = { version = "0.28", features = ["arbitrary_precision"] }
+```