Changed

• Removed remaining Go 1.22 support.

Fixed

• #306: do not emit incompatible version feature gates when serializing WIT. For example, if a world with version 0.1.0 includes a world from another package with a @since(version = 0.2.0) feature gate, then strip that feature gate when serializing to WIT if the version is greater than the world’s package version.
• #350: correctly align record size to the highest alignment of its fields, per specification.
• #352: do not use tuple types as data shape for variant or result types, as they may contain a bool or not be packed.
• #356: sort WIT packages topologically by dependency before matching WIT world when generating Go bindings. Warn if there is an ambiguous match.
• Updated package cm to v0.3.0 with multiple fixes, including a breaking change to cm.BoolResult.

Fixed

• Files generated by wit-bindgen-go generate no longer have the execute bit set.
• Updated package cm to v0.2.2 with error handling fixes.

Changed

• Updated package cm to v0.2.1 with JSON fixes.

Added

• Initial support for Component Model async types stream, future, and error-context.
• Initial support for JSON serialization of WIT list, enum, and record types.
• wasm-tools is now vendored as a WebAssembly module, executed using Wazero. This allows package wit and wit-bindgen-go to run on any supported platform without needing to separately install wasm-tools.

Changed

• Breaking: generated *.wasm.go files will now have correct WIT kebab-case base name. Interfaces or worlds with - in their name will require removal of the previous *.wasm.go files.
• Breaking: upgraded to wasm-tools v1.227.1, which removes support for multiple return values and flags with > 32 values. To ease migration, this package will continue to support JSON generated by wasm-tools v1.225.0 and earlier.
• Dropped support for TinyGo v0.32.0 and v0.33.0.
• Added support for Go 1.24 and dropped support for Go 1.22.

Fixed

• #281: errors from internal wasm-tools calls are no longer silently ignored. This required fixing a number of related issues, including synthetic world packages for Component Model metadata generation, WIT generation, and WIT keyword escaping in WIT package or interface names.
• #284: do not use bool for variant or result GC shapes. TinyGo returns result and variant values with bool as 0 or 1, which breaks the memory representation of tagged unions (variants).
• #288: correctly report the wasm32 ABI alignment of list<T> as 4, rather than 8.
• #306: run wasm-tools with the --all-features argument so feature-gated WIT is correctly found when synthesizing Component Model metadata for a Go package.

Changed

• Breaking: package cm is now a separate module. This change was made in order to minimize the runtime dependencies of programs that depend on package cm but not the rest of the packages in this module. To update your code that depends on package cm, run go get -u go.bytecodealliance.org/....

Fixed

• #264: fix lowering for imported functions that return named bool types.

Added

• wit-bindgen-go wit now accepts an --interface argument in the form of monotonic-clock, wasi:clocks/monotonic-clock, or wasi:clocks/monotonic-clock@0.2.0. This filters the serialized WIT to a specific interface and the other interface(s) it references. This can be used to generate focused WIT with a minimal set of dependencies, and can be combined with the --world argument to filter serialized WIT to the intersection of a specific world and interface.

Fixed

• #240: correctly handle cyclical data structures when generating variant lowering code.

Changed

• Breaking: package wit no longer interprets - to read from stdin when loading JSON or WIT using wit.LoadJSON or wit.LoadWIT. Use wit.DecodeJSON or wit.DecodeWIT to read JSON or WIT from an io.Reader.
• Breaking: wit.ParseWIT has been removed. Use wit.DecodeWIT(bytes.NewReader(b)) instead.

This module has been renamed. Going forward, please use go.bytecodealliance.org instead of github.com/bytecodealliance/wasm-tools-go.

Added

• wit-bindgen-go now accepts arguments that control the level of logging output on stderr. Verbose mode (-v or --verbose) will print informational log lines, warnings, and errors. Debug mode (-vv or --debug) will emit finer-grained debugging information. By default, wit-bindgen-go will print warnings or errors.
• New method (cm.Result).Result() (ok OK, err Err, isErr bool) added to streamline common patterns using result types. It has a value receiver, allowing it to be chained off a function call that returns a Result, eliminating the need to declare a temporary variable. For example: stream, err, isErr := stream.BlockingRead(n)

Fixed

• #215: generate variant accessor methods with the correct scope for Go names.

New Contributors

• @vados-cosmonic: #212 and #214 — verbose logging controls in wit-bindgen-go.

Added

• Go type aliases are now generated for each WIT type alias (type foo = bar). Deep chains of type aliases (type b = a; type c = b;) are fully supported. Generated documentation now reflects whether a type is an alias. Fixes #204.
• go:wasmimport and go:wasmexport functions are now generated in a separate .wasm.go file. This helps enable testing or use of generated packages outside of WebAssembly.
• wit-bindgen-go generate now generates a WIT file for each WIT world in its corresponding Go package directory. For example the wasi:http/proxy world would generate wasi/http/proxy/proxy.wit.
• wit-bindgen-go wit now accepts a --world argument in the form of imports, wasi:clocks/imports, or wasi:clocks/imports@0.2.0. This filters the serialized WIT to a specific world and interfaces it references. This can be used to generate focused WIT for a specific world with a minimal set of dependencies.

Changed

• Method wit.(*Package).WIT() now interprets the non-empty string name argument as signal to render in single-file, multi-package braced form.
• wit.(*Resolve).WIT() and wit.(*Package).WIT() now accept a *wit.World as context to filter serialized WIT to a specific world.
• Packages are now sorted topologically by dependency in generated WIT files. For example, wasi:cli would be followed by its dependencies like wasi:io, wasi:filesystem, or wasi:random.

Added

• Generated variant shape types (...Shape) now include structs.HostLayout.