chore: release json2xml 6.3.0

HISTORY.rst

@@ -1,4 +1,14 @@
 
+6.3.0 / 2026-06-10
+==================
+
+  * feat: reduce pure Python serializer allocations in hot dict, list, and scalar paths
+  * feat: preserve XML output semantics while reusing validated element-name and attribute work
+  * perf: lower peak memory pressure for large conversions after the 6.2.0 Rust bytes-writer release
+  * docs: add hyperfine Rust memory benchmark notes with reproduction details and the measured throughput tradeoff
+  * chore: release ``json2xml-rs`` 0.4.0 and require it from ``json2xml[fast]`` for accelerated installs
+
+
 6.2.0 / 2026-06-05
 ==================
 

RELEASE_NOTES.md

@@ -0,0 +1,33 @@
+# json2xml 6.3.0 and json2xml_rs 0.4.0
+
+Released 2026-06-10.
+
+## Highlights
+
+- Reduced allocation pressure in the pure Python serializer hot paths for dicts, lists, scalar values, XML names, and emitted attributes.
+- Kept the Python and Rust release line aligned: `json2xml[fast]` now requires `json2xml-rs>=0.4.0`.
+- Documented the Rust memory benchmark in enough detail to reproduce the 100,000-record RSS measurement and understand the throughput tradeoff.
+
+## Why Upgrade
+
+This release is focused on large conversion workloads. The 6.2.0 Rust release moved accelerator output directly into Python bytes to reduce peak serializer memory; 6.3.0 follows that with Python-side allocation reductions so fallback and unsupported-option paths also benefit.
+
+No XML shape changes are intended. Existing callers should see the same output for supported options, including invalid-name normalization, `@attrs`/`@val` handling, list wrapping, XPath mode, and pure Python fallback behavior.
+
+## Package Versions
+
+- Python package: `json2xml==6.3.0`
+- Rust accelerator package: `json2xml-rs==0.4.0`
+- Fast install: `pip install "json2xml[fast]"`
+
+## Changelog
+
+- `feat`: reduce pure Python serializer allocations in hot dict, list, and scalar paths.
+- `feat`: preserve XML output semantics while reusing validated element-name and attribute work.
+- `perf`: lower peak memory pressure for large conversions after the 6.2.0 Rust bytes-writer release.
+- `docs`: add hyperfine Rust memory benchmark notes with reproduction details and the measured throughput tradeoff.
+- `chore`: release `json2xml-rs` 0.4.0 and require it from `json2xml[fast]` for accelerated installs.
+
+## Verification
+
+The release changes are covered by the existing serializer, fast-backend, and Rust parity tests. The benchmark documentation records the measurement setup separately from the functional test suite so release consumers can reproduce performance results on their own hardware.

json2xml/__init__.py

@@ -2,4 +2,4 @@
 
 __author__ = """Vinit Kumar"""
 __email__ = "mail@vinitkumar.me"
-__version__ = "6.2.0"
+__version__ = "6.3.0"

lat.md/architecture.md

@@ -32,9 +32,9 @@ Release and CI workflows install the pinned Rust toolchain before building wheel
 
 ## Release packaging
 
-Package releases keep the Python wrapper and Rust accelerator versioned together so optional fast installs receive compatible wheels.
+Package releases keep the Python wrapper and Rust accelerator requirements aligned so optional fast installs receive compatible wheels.
 
-The Python package version lives in `pyproject.toml` and `json2xml/__init__.py`. The Rust accelerator version lives in both `rust/Cargo.toml` and `rust/pyproject.toml`, and the Python `fast` extra should require the Rust package version that contains any expected accelerator behavior.
+The Python package version lives in `pyproject.toml` and `json2xml/__init__.py`. The Rust accelerator version lives in both `rust/Cargo.toml` and `rust/pyproject.toml`, and the Python `fast` extra should require the Rust package version that contains any expected accelerator behavior. Release notes live in `HISTORY.rst`, with the current release also summarized in `RELEASE_NOTES.md` for tag and PyPI copy.
 
 ## Performance benchmarks
 

pyproject.toml

@@ -4,7 +4,7 @@ build-backend = "setuptools.build_meta"
 
 [project]
 name = "json2xml"
-version = "6.2.0"
+version = "6.3.0"
 description = "Simple Python Library to convert JSON to XML"
 readme = "README.rst"
 requires-python = ">=3.10"
@@ -50,7 +50,7 @@ dev = [
     "pygments>=2.20.0",
     "xmltodict>=0.12.0",
 ]
-fast = ["json2xml-rs>=0.3.0"]
+fast = ["json2xml-rs>=0.4.0"]
 
 [tool.pytest.ini_options]
 testpaths = ["tests"]

rust/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "json2xml_rs"
-version = "0.3.0"
+version = "0.4.0"
 edition = "2024"
 rust-version = "1.96"
 description = "Fast native JSON to XML conversion for Python"

rust/README.md

@@ -76,9 +76,10 @@ The Rust implementation is expected to be 5-15x faster than pure Python for:
 - Type dispatch (compiled match statements vs. `isinstance()` chains)
 - String building (pre-allocated buffers vs. f-string concatenation)
 
-Version 0.3.0 writes serializer output directly into Python bytes, reducing the
+Version 0.4.0 builds on the direct Python bytes writer with lower allocation
+pressure in hot serializer paths. The previous 0.3.0 release reduced the
 measured serializer RSS delta for a 100,000-record benchmark by about 49%
-compared with the previous Rust implementation.
+compared with the earlier Rust implementation.
 
 ## Limitations
 

rust/pyproject.toml

@@ -4,7 +4,7 @@ build-backend = "maturin"
 
 [project]
 name = "json2xml_rs"
-version = "0.3.0"
+version = "0.4.0"
 description = "Fast native JSON to XML conversion - Rust extension for json2xml"
 readme = "README.md"
 requires-python = ">=3.9"