Improve ergonomics - rebuild Reader around native utf-8 string types

.github/workflows/rust.yml

@@ -14,7 +14,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
     - uses: actions/checkout@v4
-    - uses: dtolnay/rust-toolchain@1.79.0
+    - uses: dtolnay/rust-toolchain@1.86.0
     - run: cargo check
 
   minimal-versions:

Cargo.toml

@@ -10,7 +10,7 @@ repository = "https://github.com/tafia/quick-xml"
 keywords = ["xml", "serde", "parser", "writer", "html"]
 categories = ["asynchronous", "encoding", "parsing", "parser-implementations"]
 license = "MIT"
-rust-version = "1.79"
+rust-version = "1.86"
 # We exclude tests & examples & benches to reduce the size of a package.
 # Unfortunately, this is source of warnings in latest cargo when packaging:
 # > warning: ignoring {context} `{name}` as `{path}` is not included in the published package
@@ -123,7 +123,7 @@ async-tokio = ["tokio"]
 ## let mut buf = Vec::new();
 ## let mut unsupported = false;
 ## loop {
-##     if !reader.decoder().encoding().is_ascii_compatible() {
+##     if !reader.encoding().is_ascii_compatible() {
 ##         unsupported = true;
 ##         break;
 ##     }

Changelog.md

@@ -14,12 +14,57 @@
 
 ## Unreleased
 
-### New Features
-
-### Bug Fixes
+This is a large release. The primary change is an ergonomic improvement across the entire API -
+the quick_xml now makes use of `&str` and `String` types where possible instead of
+`&[u8]` and `Vec<u8>`. This requires significant refactoring of downstream code,
+but should result in a net simplification as well as potential performance improvements.
+
+The MSRV has been raised to 1.86.
+
+### Breaking Changes
+
+- [#963]: Reader now validates that input is valid UTF-8 when constructing events.
+  Non-UTF-8 input passed to `Reader::from_reader()` without `DecodingReader` will now
+  produce `Error::Encoding` instead of silently passing through invalid bytes.
+  Use `DecodingReader` to transcode non-UTF-8 sources.
+- [#963]: Name types (`QName`, `LocalName`, `Prefix`, `Namespace`, `PrefixDeclaration`)
+  now wrap `&str` instead of `&[u8]`. `into_inner()` returns `&str`, and `AsRef<str>`
+  is implemented (`AsRef<[u8]>` has been removed). `ResolveResult::Unknown` now contains `String`
+  instead of `Vec<u8>`, and `NamespaceError` variants contain `String` instead of `Vec<u8>`.
+- [#963]: Removed the `decoder: Decoder` field from event types (`BytesStart`, `BytesText`,
+  `BytesCData`, `BytesRef`) and `Attributes`. The `decoder()` method is no longer available
+  on these types. Decode methods on events now always assume UTF-8 input.
+  `Error::missed_end()` no longer takes a `Decoder` parameter.
+- [#963]: Event types (`BytesStart`, `BytesEnd`, `BytesText`, `BytesCData`, `BytesPI`,
+  `BytesRef`) now store `Cow<str>` internally instead of `Cow<[u8]>`. `into_inner()` on
+  `BytesText`, `BytesCData`, `BytesPI`, and `BytesRef` now returns `Cow<str>`.
+  `BytesStart::set_name()` now takes `&str` instead of `&[u8]`.
+- [#963]: All event types and the `Event` enum now implement `Deref<Target = str>`
+  instead of `Deref<Target = [u8]>`. Explicit `AsRef<str>` impls are provided to
+  avoid ambiguity.
+- [#963]: Removed `decode()` methods from `BytesText`, `BytesCData`, and `BytesRef`.
+  Content is already available as `&str` via `Deref`. The `xml10_content()`,
+  `xml11_content()`, `xml_content()`, and `html_content()` methods now return
+  `Cow<str>` directly instead of `Result<Cow<str>, EncodingError>`.
+- [#963]: `Attribute::value` is now `Cow<'a, str>` instead of `Cow<'a, [u8]>`.
+  The `From<(&[u8], &[u8])>` impl has been removed.
+- [#963]: `BytesDecl::version()`, `encoding()`, and `standalone()` now return
+  `Cow<'_, str>` instead of `Cow<'_, [u8]>`.
+- [#963]: Removed `Reader::decoder()` method. Use `Reader::encoding()` instead
+  (available with the `encoding` feature). Removed `decoder()` from the `XmlRead`
+  serde trait. Removed all methods from `Decoder` (the struct is kept only for
+  backward compatibility with deprecated `Attribute` methods).
 
 ### Misc Changes
 
+- [#963]: MSRV bumped to 1.86 (April 2025)
+- [#963]: Deprecated `Attribute` methods that take a `Decoder` parameter, since
+  attribute values are now always valid UTF-8: `decoded_and_normalized_value()`,
+  `decoded_and_normalized_value_with()`, `decode_and_unescape_value()`, and
+  `decode_and_unescape_value_with()`. Use `normalized_value()` and
+  `normalized_value_with()` instead.
+
+[#963]: https://github.com/tafia/quick-xml/pull/963
 
 ## 0.41.0 -- 2026-06-29
 
@@ -48,7 +93,6 @@
 [#969]: https://github.com/tafia/quick-xml/issues/969
 [#970]: https://github.com/tafia/quick-xml/issues/970
 
-
 ## 0.40.1 -- 2026-05-15
 
 ### Bug Fixes
@@ -65,14 +109,11 @@
 
 [#964]: https://github.com/tafia/quick-xml/pull/964
 
-### Misc Changes
-
-
 ## 0.40.0 -- 2026-05-11
 
 MSRV bumped to 1.79.
 
-Now `quick-xml` supports the UTF-16 encoded documents. See the new `DecodingReader` type.
+Now `quick-xml` supports UTF-16 encoded documents. See the new `DecodingReader` type.
 
 ### New Features
 

README.md

@@ -4,7 +4,7 @@
 [![Crate](https://img.shields.io/crates/v/quick-xml.svg)](https://crates.io/crates/quick-xml)
 [![docs.rs](https://docs.rs/quick-xml/badge.svg)](https://docs.rs/quick-xml)
 [![codecov](https://img.shields.io/codecov/c/github/tafia/quick-xml)](https://codecov.io/gh/tafia/quick-xml)
-[![MSRV](https://img.shields.io/badge/rustc-1.79.0+-ab6000.svg)](https://blog.rust-lang.org/2024/06/13/Rust-1.79.0/)
+[![MSRV](https://img.shields.io/badge/rustc-1.86.0+-ab6000.svg)](https://blog.rust-lang.org/2025/04/03/Rust-1.86.0/)
 
 High performance xml pull reader/writer.
 

benches/macrobenches.rs

@@ -54,11 +54,11 @@ fn parse_document_from_str(doc: &str) -> XmlResult<()> {
             }
             Event::Start(e) | Event::Empty(e) => {
                 for attr in e.attributes() {
-                    black_box(attr?.decoded_and_normalized_value(version, r.decoder())?);
+                    black_box(attr?.normalized_value(version)?);
                 }
             }
             Event::Text(e) => {
-                black_box(e.xml10_content()?);
+                black_box(e.xml10_content());
             }
             Event::CData(e) => {
                 black_box(e.into_inner());
@@ -82,11 +82,11 @@ fn parse_document_from_bytes(doc: &[u8]) -> XmlResult<()> {
             }
             Event::Start(e) | Event::Empty(e) => {
                 for attr in e.attributes() {
-                    black_box(attr?.decoded_and_normalized_value(version, r.decoder())?);
+                    black_box(attr?.normalized_value(version)?);
                 }
             }
             Event::Text(e) => {
-                black_box(e.xml10_content()?);
+                black_box(e.xml10_content());
             }
             Event::CData(e) => {
                 black_box(e.into_inner());
@@ -111,11 +111,11 @@ fn parse_document_from_str_with_namespaces(doc: &str) -> XmlResult<()> {
             (resolved_ns, Event::Start(e) | Event::Empty(e)) => {
                 black_box(resolved_ns);
                 for attr in e.attributes() {
-                    black_box(attr?.decoded_and_normalized_value(version, r.decoder())?);
+                    black_box(attr?.normalized_value(version)?);
                 }
             }
             (resolved_ns, Event::Text(e)) => {
-                black_box(e.xml10_content()?);
+                black_box(e.xml10_content());
                 black_box(resolved_ns);
             }
             (resolved_ns, Event::CData(e)) => {
@@ -142,11 +142,11 @@ fn parse_document_from_bytes_with_namespaces(doc: &[u8]) -> XmlResult<()> {
             (resolved_ns, Event::Start(e) | Event::Empty(e)) => {
                 black_box(resolved_ns);
                 for attr in e.attributes() {
-                    black_box(attr?.decoded_and_normalized_value(version, r.decoder())?);
+                    black_box(attr?.normalized_value(version)?);
                 }
             }
             (resolved_ns, Event::Text(e)) => {
-                black_box(e.xml10_content()?);
+                black_box(e.xml10_content());
                 black_box(resolved_ns);
             }
             (resolved_ns, Event::CData(e)) => {

benches/microbenches.rs

@@ -146,7 +146,7 @@ fn one_event(c: &mut Criterion) {
             config.trim_text(true);
             config.check_end_names = false;
             match r.read_event() {
-                Ok(Event::Comment(e)) => nbtxt += e.xml10_content().unwrap().len(),
+                Ok(Event::Comment(e)) => nbtxt += e.xml10_content().len(),
                 something_else => panic!("Did not expect {:?}", something_else),
             };
 
@@ -225,7 +225,7 @@ fn attributes(c: &mut Criterion) {
             let mut count = black_box(0);
             loop {
                 match r.read_event() {
-                    Ok(Event::Empty(e)) if e.name() == QName(b"player") => {
+                    Ok(Event::Empty(e)) if e.name() == QName("player") => {
                         for name in ["num", "status", "avg"] {
                             if let Some(_attr) = e.try_get_attribute(name).unwrap() {
                                 count += 1

examples/custom_entities.rs

@@ -12,16 +12,14 @@
 
 use std::borrow::Cow;
 use std::collections::{HashMap, VecDeque};
-use std::str::from_utf8;
 
-use quick_xml::encoding::Decoder;
 use quick_xml::errors::Error;
 use quick_xml::escape::EscapeError;
 use quick_xml::events::{BytesEnd, BytesStart, BytesText, Event};
 use quick_xml::name::QName;
 use quick_xml::reader::Reader;
 use quick_xml::XmlVersion;
-use regex::bytes::Regex;
+use regex::Regex;
 
 use pretty_assertions::assert_eq;
 
@@ -31,7 +29,7 @@ struct MyReader<'i> {
     readers: VecDeque<Reader<&'i [u8]>>,
     /// Map of captured internal _parsed general entities_. _Parsed_ means that
     /// value of the entity is parsed by XML reader
-    entities: HashMap<&'i [u8], &'i [u8]>,
+    entities: HashMap<&'i str, &'i str>,
     /// In this example we use simple regular expression to capture entities from DTD.
     /// In real application you should use DTD parser.
     entity_re: Regex,
@@ -71,7 +69,7 @@ impl<'i> MyReader<'i> {
                             self.readers.push_back(reader);
                             return Ok(Event::Text(BytesText::from_escaped(ch.to_string())));
                         }
-                        let mut r = Reader::from_reader(self.resolve(&e)?);
+                        let mut r = Reader::from_reader(self.resolve(&e)?.as_bytes());
                         *r.config_mut() = reader.config().clone();
 
                         self.readers.push_back(reader);
@@ -100,33 +98,20 @@ impl<'i> MyReader<'i> {
             Cow::Owned(_) => unreachable!("We are sure that event will be borrowed"),
         };
         for cap in self.entity_re.captures_iter(doctype) {
-            self.entities.insert(
-                cap.get(1).unwrap().as_bytes(),
-                cap.get(2).unwrap().as_bytes(),
-            );
+            self.entities
+                .insert(cap.get(1).unwrap().as_str(), cap.get(2).unwrap().as_str());
         }
     }
 
-    fn resolve(&self, entity: &[u8]) -> Result<&'i [u8], EscapeError> {
+    fn resolve(&self, entity: &str) -> Result<&'i str, EscapeError> {
         match self.entities.get(entity) {
             Some(replacement) => Ok(replacement),
-            None => Err(EscapeError::UnrecognizedEntity(
-                0..0,
-                String::from_utf8_lossy(entity).into_owned(),
-            )),
+            None => Err(EscapeError::UnrecognizedEntity(0..0, entity.to_owned())),
         }
     }
 
     fn get_entity(&self, entity: &str) -> Option<&'i str> {
-        self.entities
-            .get(entity.as_bytes())
-            // SAFETY: We are sure that slices are correct UTF-8 because we get
-            // them from rust string
-            .map(|value| from_utf8(value).unwrap())
-    }
-
-    fn decoder(&self) -> Decoder {
-        self.readers.back().unwrap().decoder()
+        self.entities.get(entity).copied()
     }
 }
 
@@ -154,14 +139,9 @@ fn main() -> Result<(), Box<dyn std::error::Error>> {
         let mut attrs = e.attributes();
 
         let label = attrs.next().unwrap()?;
-        assert_eq!(label.key, QName(b"label"));
+        assert_eq!(label.key, QName("label"));
         assert_eq!(
-            label.decoded_and_normalized_value_with(
-                XmlVersion::Implicit1_0,
-                reader.decoder(),
-                9,
-                |e| reader.get_entity(e)
-            )?,
+            label.normalized_value_with(XmlVersion::Implicit1_0, 9, |e| reader.get_entity(e))?,
             "Message: hello world"
         );
 
@@ -190,14 +170,9 @@ fn main() -> Result<(), Box<dyn std::error::Error>> {
         let mut attrs = e.attributes();
 
         let attr = attrs.next().unwrap()?;
-        assert_eq!(attr.key, QName(b"attr"));
+        assert_eq!(attr.key, QName("attr"));
         assert_eq!(
-            attr.decoded_and_normalized_value_with(
-                XmlVersion::Implicit1_0,
-                reader.decoder(),
-                9,
-                |e| { reader.get_entity(e) }
-            )?,
+            attr.normalized_value_with(XmlVersion::Implicit1_0, 9, |e| { reader.get_entity(e) })?,
             "Message: hello world"
         );
 

examples/nested_readers.rs

@@ -22,7 +22,7 @@ fn main() -> Result<(), quick_xml::Error> {
     loop {
         match reader.read_event_into(&mut buf)? {
             Event::Start(element) => {
-                if let b"w:tbl" = element.name().as_ref() {
+                if element.name().as_ref() == "w:tbl" {
                     count += 1;
                     let mut stats = TableStat {
                         index: count,
@@ -35,20 +35,17 @@ fn main() -> Result<(), quick_xml::Error> {
                         skip_buf.clear();
                         match reader.read_event_into(&mut skip_buf)? {
                             Event::Start(element) => match element.name().as_ref() {
-                                b"w:tr" => {
+                                "w:tr" => {
                                     stats.rows.push(vec![]);
                                     row_index = stats.rows.len() - 1;
                                 }
-                                b"w:tc" => {
-                                    stats.rows[row_index].push(
-                                        String::from_utf8(element.name().as_ref().to_vec())
-                                            .unwrap(),
-                                    );
+                                "w:tc" => {
+                                    stats.rows[row_index].push(element.name().as_ref().to_string());
                                 }
                                 _ => {}
                             },
                             Event::End(element) => {
-                                if element.name().as_ref() == b"w:tbl" {
+                                if element.name().as_ref() == "w:tbl" {
                                     found_tables.push(stats);
                                     break;
                                 }

examples/read_buffered.rs

@@ -18,7 +18,6 @@ fn main() -> Result<(), quick_xml::Error> {
         match reader.read_event_into(&mut buf) {
             Ok(Event::Start(ref e)) => {
                 let name = e.name();
-                let name = reader.decoder().decode(name.as_ref())?;
                 println!("read start event {:?}", name.as_ref());
                 count += 1;
             }