merge: wit-bindgen 0.42

Merge upstream wit-bindgen 0.42.0 into the vendored bindgen subtree.

- Bump wit-bindgen-core 0.41 -> 0.42 and wit-parser 0.227 -> 0.230.
- Adapt to the wit-parser 0.230 API break: `TypeDefKind` gained a
  `FixedSizeList(Type, u32)` variant. Handle it in the introspection async-path
  walk like a `List` (element indexed by a wildcard path), and add arms to the
  Rust and Go generators' type/codec matches. Full fixed-size-list code
  generation is not supported yet (upstream adds Rust support in bytecodealliance/wit-bindgen#1277, ported
  later at 0.52), so the generator arms panic with an "unsupported" message;
  no fixture exercises them.
- Port upstream features bytecodealliance/wit-bindgen#1244 + bytecodealliance/wit-bindgen#1270 (`serde::Deserialize` for the bindgen
  config): gate `serde::Deserialize` derives on `Opts` (`serde(default,
  rename_all = "kebab-case")`) and `WithOption` (`rename_all = "kebab-case"`)
  behind a new optional `serde` feature, matching upstream. wRPC has neither
  `ExportKey`/`AsyncConfig`/`Ownership` config types nor an `async_` option, so
  only `Opts`/`WithOption` apply.

Non-carries (not applicable to wRPC, dropped from the merge):
- more `wit-bindgen test` subcommand backends (`crates/test/src/{csharp,
  moonbit}.rs`, `crates/test/LICENSE-*`) and the new `tests/runtime-async/`
  guest runtime test tree; wRPC keeps its own `wrpc-test` crate.
- the async-task / futures-stream-ABI refactors (bytecodealliance/wit-bindgen#1233/bytecodealliance/wit-bindgen#1241/bytecodealliance/wit-bindgen#1249/bytecodealliance/wit-bindgen#1260/bytecodealliance/wit-bindgen#1264/
  bytecodealliance/wit-bindgen#1268/bytecodealliance/wit-bindgen#1278/bytecodealliance/wit-bindgen#1279/bytecodealliance/wit-bindgen#1247/bytecodealliance/wit-bindgen#1240/bytecodealliance/wit-bindgen#1291/bytecodealliance/wit-bindgen#1306 etc.) and bytecodealliance/wit-bindgen#1214's canonical-ABI
  guest-code warning squashing do not apply to wRPC's transport-stub generator.

rust codegen (237) and go codegen (79) tests pass; `cargo clippy --workspace`
(and `--features serde`) and `cargo doc --workspace` are clean; wasmtime and all
examples build.

Assisted-by: claude:claude-opus-4-8
Upstream diff: bytecodealliance/wit-bindgen@v0.41.0...v0.42.0

Author: rvolosatovs

Cargo.lock

@@ -184,14 +184,14 @@ wasmtime-cli-flags = { version = "45", default-features = false }
 wasmtime-wasi = { version = "45", default-features = false }
 wasmtime-wasi-http = { version = "45", default-features = false }
 wit-bindgen = { version = "0.45", default-features = false }
-wit-bindgen-core = { version = "0.41", default-features = false }
+wit-bindgen-core = { version = "0.42", default-features = false }
 wit-bindgen-wrpc = { version = "0.11", default-features = false, path = "./crates/wit-bindgen" }
 wit-bindgen-wrpc-go = { version = "0.13", default-features = false, path = "./crates/wit-bindgen-go" }
 wit-bindgen-wrpc-rust = { version = "0.11", default-features = false, path = "./crates/wit-bindgen-rust" }
 wit-bindgen-wrpc-rust-macro = { version = "0.11", default-features = false, path = "./crates/wit-bindgen-rust-macro" }
 wit-bindgen-wrpc-test = { version = "0.1", default-features = false, path = "./crates/wit-bindgen-test" }
 wit-component = { version = "0.252", default-features = false }
-wit-parser = { version = "0.227", default-features = false }
+wit-parser = { version = "0.230", default-features = false }
 wrpc-cli = { version = "0.8", path = "./crates/cli", default-features = false }
 wrpc-introspect = { version = "0.7", default-features = false, path = "./crates/introspect" }
 wrpc-nats = { version = "0.1", path = "./crates/nats", default-features = false }

Cargo.toml

@@ -123,6 +123,18 @@ pub fn async_paths_tyid(resolve: &Resolve, id: TypeId) -> (BTreeSet<VecDeque<Opt
             }
             (paths, false)
         }
+        TypeDefKind::FixedSizeList(ty, _) => {
+            let mut paths = BTreeSet::default();
+            let (nested, fut) = async_paths_ty(resolve, ty);
+            for mut path in nested {
+                path.push_front(None);
+                paths.insert(path);
+            }
+            if fut {
+                paths.insert(vec![None].into());
+            }
+            (paths, false)
+        }
         TypeDefKind::Option(ty) => async_paths_ty(resolve, ty),
         TypeDefKind::Result(ty) => {
             let mut paths = BTreeSet::default();

crates/introspect/src/lib.rs

@@ -1403,6 +1403,7 @@ impl InterfaceGenerator<'_> {
             TypeDefKind::Option(ty) => self.print_read_option(ty, reader, path),
             TypeDefKind::Result(ty) => self.print_read_result(ty, reader, path),
             TypeDefKind::List(ty) => self.print_read_list(ty, reader, path),
+            TypeDefKind::FixedSizeList(..) => panic!("unsupported type: fixed size list"),
             TypeDefKind::Future(ty) => self.print_read_future(ty, reader, path),
             TypeDefKind::Stream(ty) => self.print_read_stream(ty, reader, path),
             TypeDefKind::Type(ty) => {
@@ -3332,6 +3333,9 @@ func ServeInterface(s {wrpc}.Server, h Handler) (stop func() error, err error) {
         }
         match &ty.kind {
             TypeDefKind::List(ty) => self.print_list(ty),
+            TypeDefKind::FixedSizeList(..) => {
+                panic!("unsupported anonymous type reference: fixed size list")
+            }
             TypeDefKind::Option(ty) => self.print_option(ty, decl),
             TypeDefKind::Result(ty) => self.print_result(ty),
             TypeDefKind::Variant(_) => panic!("unsupported anonymous variant"),

crates/wit-bindgen-go/src/interface.rs

@@ -17,11 +17,15 @@ repository.workspace = true
 test = false
 doctest = false
 
+[features]
+serde = ["dep:serde"]
+
 [dependencies]
 anyhow = { workspace = true }
 clap = { workspace = true, features = ["derive", "std"], optional = true }
 heck = { workspace = true }
 prettyplease = { workspace = true }
+serde = { workspace = true, features = ["derive"], optional = true }
 syn = { workspace = true, features = ["parsing"] }
 wit-bindgen-core = { workspace = true }
 wrpc-introspect = { workspace = true }

crates/wit-bindgen-rust/Cargo.toml

@@ -1056,6 +1056,9 @@ pub fn serve_interface<'a, T: {wrpc_transport}::Serve>(
         }
         match &ty.kind {
             TypeDefKind::List(ty) => self.print_list(ty, owned, submodule),
+            TypeDefKind::FixedSizeList(..) => {
+                panic!("unsupported anonymous type reference: fixed size list")
+            }
             TypeDefKind::Option(ty) => self.print_option(ty, owned, submodule),
             TypeDefKind::Result(ty) => self.print_result(ty, owned, submodule),
             TypeDefKind::Variant(_) => panic!("unsupported anonymous variant"),
@@ -2279,7 +2282,7 @@ mod {mod_name} {{
                 .additional_derive_ignore
                 .contains(&name.to_kebab_case())
             {
-                derives.extend(self.r#gen.opts.additional_derive_attributes.to_vec());
+                derives.extend(self.r#gen.opts.additional_derive_attributes.iter().cloned());
             }
             derives.extend(
                 [

crates/wit-bindgen-rust/src/interface.rs

@@ -101,13 +101,18 @@ fn parse_with(s: &str) -> Result<(String, WithOption), String> {
 
 #[derive(Default, Debug, Clone)]
 #[cfg_attr(feature = "clap", derive(clap::Parser))]
+#[cfg_attr(
+    feature = "serde",
+    derive(serde::Deserialize),
+    serde(default, rename_all = "kebab-case")
+)]
 pub struct Opts {
     /// Whether or not a formatter is executed to format generated code.
     #[cfg_attr(feature = "clap", arg(long))]
     pub format: bool,
 
     /// Names of functions to skip generating bindings for.
-    #[cfg_attr(feature = "clap", arg(long))]
+    #[cfg_attr(feature = "clap", arg(long, value_name = "NAME"))]
     pub skip: Vec<String>,
 
     /// The optional path to the bitflags crate to use.
@@ -120,7 +125,7 @@ pub struct Opts {
     /// specified multiple times to add multiple attributes.
     ///
     /// These derive attributes will be added to any generated structs or enums
-    #[cfg_attr(feature = "clap", arg(long, short = 'd'))]
+    #[cfg_attr(feature = "clap", arg(long, short = 'd', value_name = "DERIVE"))]
     pub additional_derive_attributes: Vec<String>,
 
     /// Variants and records to ignore when applying additional derive attributes.
@@ -129,7 +134,7 @@ pub struct Opts {
     /// This feature allows some variants and records to use types for which adding traits will cause
     /// compilation to fail, such as serde::Deserialize on wasi:io/streams.
     ///
-    #[cfg_attr(feature = "clap", arg(long))]
+    #[cfg_attr(feature = "clap", arg(long, value_name = "NAME"))]
     pub additional_derive_ignore: Vec<String>,
 
     /// Remapping of interface names to rust module names.
@@ -152,31 +157,31 @@ pub struct Opts {
     /// The optional path to the `anyhow` crate to use.
     ///
     /// This defaults to `wit_bindgen_wrpc::anyhow`.
-    #[cfg_attr(feature = "clap", arg(long))]
+    #[cfg_attr(feature = "clap", arg(long, value_name = "PATH"))]
     pub anyhow_path: Option<String>,
 
     /// The optional path to the `bytes` crate to use.
     ///
     /// This defaults to `wit_bindgen_wrpc::bytes`.
-    #[cfg_attr(feature = "clap", arg(long))]
+    #[cfg_attr(feature = "clap", arg(long, value_name = "PATH"))]
     pub bytes_path: Option<String>,
 
     /// The optional path to the `futures` crate to use.
     ///
     /// This defaults to `wit_bindgen_wrpc::futures`.
-    #[cfg_attr(feature = "clap", arg(long))]
+    #[cfg_attr(feature = "clap", arg(long, value_name = "PATH"))]
     pub futures_path: Option<String>,
 
     /// The optional path to the `tokio` crate to use.
     ///
     /// This defaults to `wit_bindgen_wrpc::tokio`.
-    #[cfg_attr(feature = "clap", arg(long))]
+    #[cfg_attr(feature = "clap", arg(long, value_name = "PATH"))]
     pub tokio_path: Option<String>,
 
     /// The optional path to the `tokio-util` crate to use.
     ///
     /// This defaults to `wit_bindgen_wrpc::tokio_util`.
-    #[cfg_attr(feature = "clap", arg(long))]
+    #[cfg_attr(feature = "clap", arg(long, value_name = "PATH"))]
     pub tokio_util_path: Option<String>,
 
     /// The optional path to the `tracing` crate to use.
@@ -773,6 +778,11 @@ enum Identifier<'a> {
 
 /// Options for with "with" remappings.
 #[derive(Debug, Clone)]
+#[cfg_attr(
+    feature = "serde",
+    derive(serde::Deserialize),
+    serde(rename_all = "kebab-case")
+)]
 pub enum WithOption {
     Path(String),
     Generate,