release: prepare 0.4.1 with FFI parity, binding improvements, docs sync

Add Schematron and CSS selector support to C FFI, bringing it to parity
with Rust/Python/WASM. Add tree mutation APIs to WASM binding. Add CSS
selectors to Python binding. Expand benchmarks with validation, XPath,
and CSS suites. Add 58 CSS evaluator tests and 10 FFI tests. Fix README
which incorrectly listed Schematron as unsupported and XPath as 1.0 only.
Update MIGRATION.md with HTML5, Schematron, and CSS migration examples.

Author: jonwiggins

CHANGELOG.md

@@ -5,6 +5,49 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.1.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## [0.4.1] - 2026-03-15
+
+### Added
+
+- **Schematron C FFI** — `xmloxide_parse_schematron`, `xmloxide_free_schematron`,
+  `xmloxide_validate_schematron`, and `xmloxide_validate_schematron_with_phase` for
+  C/C++ consumers; Schematron was previously only available in Rust, Python, and WASM
+- **CSS selector C FFI** — `xmloxide_css_select`, `xmloxide_css_select_first`, and
+  `xmloxide_free_nodeid_array` for querying elements with CSS selectors from C/C++
+- **CSS selectors in Python** — `css_select()` and `css_select_first()` methods on
+  `Document` in pyxmloxide
+- **WASM tree mutation APIs** — `createElement`, `createText`, `createComment`,
+  `appendChild`, `removeNode`, `setAttribute`, `removeAttribute`, `setTextContent`,
+  `insertBefore`, `cloneNode` on `WasmDocument`
+- **Validation benchmarks** — criterion benchmarks for DTD, RelaxNG, XSD, and
+  Schematron validation
+- **Expanded XPath benchmarks** — count, string function, position predicate,
+  ancestor axis, and union expression benchmarks
+- **CSS selector benchmarks** — class selector and complex combinator benchmarks
+- 58 CSS evaluator inline tests covering tag, class, ID, attribute, pseudo-class,
+  combinator, and universal selector matching
+- 10 new FFI tests (5 Schematron + 5 CSS) bringing FFI test total to 138
+
+### Fixed
+
+- **README incorrectly listed Schematron as unsupported** — the Limitations section
+  claimed "No Schematron" despite Schematron being added in 0.4.0
+- **README listed XPath as "1.0 only"** — updated to "XPath 1.0+" reflecting the
+  17+ XPath 2.0 functions added in prior releases
+- **Outdated test counts in README** — updated from 936 to 1078 unit tests
+
+### Improved
+
+- Unit tests expanded from 1010 to 1078
+- FFI tests expanded from 128 to 138
+- README now documents serde, async, and Schematron features
+- MIGRATION.md expanded with HTML5 parsing, HTML5 streaming, Schematron validation,
+  and CSS selector migration examples
+- CLAUDE.md module map updated with css/, serde_xml/, async_xml, and full ffi/ listing
+- `xmllint --schematron` added to CLI documentation in README
+- Schematron added to migration table in README
+- `xmloxide.h` header updated with Schematron and CSS selector declarations
+
 ## [0.4.0] - 2026-03-14
 
 ### Added

CLAUDE.md

@@ -4,7 +4,7 @@
 
 **xmloxide** is a pure Rust reimplementation of libxml2 — the de facto standard XML/HTML parsing library in the open-source world. libxml2 became officially unmaintained in December 2025 with known security issues. xmloxide is a memory-safe, high-performance replacement that passes the same conformance test suites.
 
-**Version:** 0.4.0
+**Version:** 0.4.1
 **License:** MIT
 **MSRV:** Rust 1.81+
 
@@ -13,11 +13,15 @@
 - Full conformance with W3C XML 1.0 (Fifth Edition) and Namespaces in XML 1.0
 - **1727/1727** W3C XML Conformance Test Suite tests passing (100%)
 - **119/119** libxml2 regression tests passing (100%)
-- Feature parity with libxml2's core: XML/HTML parsing, DOM, SAX2, XPath 1.0, XmlReader, push parser, DTD/RelaxNG/XSD/Schematron validation, C14N, XInclude, XML Catalogs
+- Feature parity with libxml2's core: XML/HTML parsing, DOM, SAX2, XPath 1.0+, XmlReader, push parser, DTD/RelaxNG/XSD/Schematron validation, C14N, XInclude, XML Catalogs
 - **WHATWG HTML5 parser** — full HTML Living Standard tokenizer (§13.2.5) and tree builder (§13.2.6) with 7032/7032 tokenizer tests + 1778/1778 tree construction tests passing (100% html5lib-tests)
+- **CSS selector engine** — query elements with familiar CSS syntax including combinators and pseudo-classes
+- **Serde integration** — optional XML (de)serialization to/from Rust types via serde
+- **Async parsing** — optional async parsing from `tokio::io::AsyncRead` sources
 - Zero `unsafe` in public API surface (`unsafe_code = "deny"` in Cargo.toml)
 - No system dependencies — pure Rust (uses `encoding_rs` for character encoding)
 - C/C++ FFI layer with header file (`include/xmloxide.h`)
+- WASM bindings (`xmloxide-wasm`) and Python bindings (`pyxmloxide`)
 - `xmllint` CLI tool
 - Performance competitive with libxml2 (serialization 1.5-2.3x faster)
 
@@ -67,7 +71,13 @@ src/
 │   ├── mod.rs          # WHATWG HTML5 parser public API and module docs
 │   ├── tokenizer.rs    # HTML5 tokenizer (all 80 states per §13.2.5)
 │   ├── tree_builder.rs # HTML5 tree construction (all insertion modes per §13.2.6)
+│   ├── sax.rs          # HTML5 SAX-like streaming API (no DOM tree)
 │   └── entities.rs     # HTML5 named character references (§13.5, 2231 entries)
+├── css/
+│   ├── mod.rs          # CSS selector public API (select, select_with)
+│   ├── parser.rs       # CSS selector parser
+│   ├── types.rs        # Selector AST types
+│   └── eval.rs         # Selector evaluator against document trees
 ├── sax/
 │   └── mod.rs          # SAX2 handler trait and streaming parser
 ├── reader/
@@ -80,7 +90,8 @@ src/
 │   ├── lexer.rs        # XPath expression tokenizer
 │   ├── parser.rs       # XPath expression parser → AST
 │   ├── eval.rs         # Expression evaluator against a node tree
-│   └── types.rs        # XPath value types (NodeSet, String, Number, Boolean)
+│   ├── types.rs        # XPath value types (NodeSet, String, Number, Boolean)
+│   └── regex.rs        # XPath regex support (matches, replace, tokenize)
 ├── validation/
 │   ├── mod.rs          # ValidationResult, ValidationError
 │   ├── dtd.rs          # DTD parsing and validation (populates id_map)
@@ -96,12 +107,27 @@ src/
 │   └── mod.rs          # XInclude 1.0 document inclusion
 ├── catalog/
 │   └── mod.rs          # OASIS XML Catalogs for URI resolution
+├── serde_xml/
+│   ├── mod.rs          # Serde XML module root (feature-gated behind "serde")
+│   ├── de.rs           # XML deserializer
+│   ├── ser.rs          # XML serializer
+│   └── error.rs        # Serde error types
+├── async_xml.rs        # Async parsing via tokio::io::AsyncRead (feature-gated "async")
 ├── ffi/
 │   ├── mod.rs          # FFI module root (feature-gated behind "ffi")
 │   ├── document.rs     # Document parsing FFI
 │   ├── tree.rs         # Tree navigation FFI
 │   ├── serial.rs       # Serialization FFI
 │   ├── xpath.rs        # XPath evaluation FFI
+│   ├── validation.rs   # DTD/RelaxNG/XSD/Schematron validation FFI
+│   ├── css.rs          # CSS selector FFI
+│   ├── sax.rs          # SAX2 streaming FFI
+│   ├── reader.rs       # XmlReader FFI
+│   ├── push.rs         # Push parser FFI
+│   ├── c14n.rs         # Canonical XML FFI
+│   ├── catalog.rs      # XML Catalogs FFI
+│   ├── html5.rs        # HTML5 parsing FFI
+│   ├── xinclude.rs     # XInclude FFI
 │   └── strings.rs      # String memory management FFI
 ├── error/
 │   └── mod.rs          # Error types, ParseError, ParseDiagnostic
@@ -213,7 +239,8 @@ These are the specs we implement against:
 
 - [XML 1.0 (Fifth Edition)](https://www.w3.org/TR/xml/) — the core spec
 - [Namespaces in XML 1.0](https://www.w3.org/TR/xml-names/) — namespace processing
-- [XPath 1.0](https://www.w3.org/TR/xpath-10/) — XPath query language
+- [XPath 1.0](https://www.w3.org/TR/xpath-10/) — XPath query language (with selected XPath 2.0 functions)
+- [ISO Schematron](https://www.iso.org/standard/40833.html) — ISO/IEC 19757-3 rule-based validation
 - [XML Inclusions (XInclude) 1.0](https://www.w3.org/TR/xinclude/) — document merging
 - [Canonical XML 1.0](https://www.w3.org/TR/xml-c14n/) — canonical serialization
 - [RelaxNG](https://relaxng.org/spec-20011203.html) — schema language
@@ -358,7 +385,7 @@ Pre-commit hooks available via `./scripts/install-hooks.sh` (runs fmt, clippy, t
 
 | Suite | Location | Tests | Notes |
 |-------|----------|-------|-------|
-| Unit tests | `src/**/*.rs` (inline) | 991 | All modules |
+| Unit tests | `src/**/*.rs` (inline) | 1020+ | All modules |
 | W3C Conformance | `tests/conformance.rs` | 1727/1727 | Requires `download-conformance-suite.sh` |
 | libxml2 Compat | `tests/libxml2_compat.rs` | 119/119 | Requires `download-libxml2-tests.sh` |
 | html5lib Tokenizer | `tests/html5lib_tokenizer.rs` | 7032/7032 | Requires `download-html5lib-tests.sh` |
@@ -367,6 +394,8 @@ Pre-commit hooks available via `./scripts/install-hooks.sh` (runs fmt, clippy, t
 | Real-world XML | `tests/real_world_xml.rs` | 22 | Atom, SVG, XHTML, Maven, SOAP, validation |
 | Security/DoS | `tests/security.rs` | 15 | Billion laughs, deep nesting, etc. |
 | Entity resolver | `tests/entity_resolver.rs` | 14 | Entity expansion edge cases |
-| FFI | `tests/ffi_tests.rs` | 112 | C API surface tests (including SAX) |
+| FFI | `tests/ffi_tests.rs` | 138+ | C API surface tests (SAX, Schematron, CSS) |
 | Schematron | `tests/schematron.rs` | 11 | PO schema, phases, firing rules, namespaces |
+| Property tests | `tests/property_tests.rs` | — | Proptest roundtrip invariants |
+| UBL Validation | `tests/ubl_validation.rs` | 2 | Real-world UBL 2.4 XSD (requires download) |
 | Fuzz targets | `fuzz/` | 11 targets | XML, HTML, HTML5, XPath, roundtrip, SAX, reader, push, validation, schematron |

Cargo.lock

@@ -1,6 +1,6 @@
 [package]
 name = "xmloxide"
-version = "0.4.0"
+version = "0.4.1"
 edition = "2021"
 rust-version = "1.81"
 license = "MIT"