Changes in bindgen.rs

4ad29c7d - fix(bindgen,format): enable wasm encoded to be used in the `bindgen!` macro (#12857)

Mon, 30 Mar 2026 12:54:55 +0000

fix(bindgen,format): enable wasm encoded to be used in the `bindgen!` macro (#12857) List of files: /wasmtime-44.0.1/crates/component-macro/src/bindgen.rs

1e0b0b46 - Remove subtask reparenting (#12570)

Mon, 23 Feb 2026 21:00:21 +0000

Remove subtask reparenting (#12570)This commit updates the implementation of component-model-asyncprimitives to remove the manual subtask reparenting process. This isrequired to fix #12544 at a semantic level because a subtask isn't everactually reparented, even if its parent exits. The first part of thischange is to remove the `GuestTask::subtasks` field and all relevantmanipulations of it.This field, however, powered the `TaskExit` abstraction returned from`call_concurrent`. This commit then subsequently deletes `TaskExit` andall related infrastructure as it's no longer directly applicable as-is.The rest of this change is then updating tests/bindings/etc to accountfor these two changes.The main semantic changes related to tests are:* `wasmtime run`, with and without `--invoke`, no longer waits for all subtasks. This instead only waits for the main task returning before exiting. Whether or not this is the correct behavior is under discussion in WebAssembly/component-model#608* `wasmtime serve` has been updated to keep the store alive at least until the response body has been fully transmitted. This is also part of WebAssembly/component-model#608.* Some `component-async-tests`-related tests were updated to either avoid blocking the store as it wasn't needed or yield enough times to ensure that the test passes.Closes #12544prtest:full List of files: /wasmtime-44.0.1/crates/component-macro/src/bindgen.rs

fb1827ee - `wit-bindgen`: Add an option to use `anyhow::Result` instead of `wasmtime::Result` (#12331)

Tue, 13 Jan 2026 18:46:48 +0000

`wit-bindgen`: Add an option to use `anyhow::Result` instead of `wasmtime::Result` (#12331)* wit-bindgen: Add an option to use `anyhow::Result` instead of `wasmtime::Result`* Add option to reference docs* Rename `anyhow` dev dependency to `anyhow-for-testing` List of files: /wasmtime-44.0.1/crates/component-macro/src/bindgen.rs

080faa1a - add `task_exit` option to `wasmtime-wit-bindgen` (#11665)

Wed, 10 Sep 2025 20:27:13 +0000

add `task_exit` option to `wasmtime-wit-bindgen` (#11665)This builds on #11662 by optionally exposing the `TaskExit` return value from`[Typed]Func::call_concurrent` in the bindings generated for exported functions.Note that the first two commits are shared with #11662.Fixes #11600Signed-off-by: Joel Dice List of files: /wasmtime-44.0.1/crates/component-macro/src/bindgen.rs

b196aef9 - Update wasm-tools crates (#11594)

Tue, 02 Sep 2025 23:22:18 +0000

Update wasm-tools crates (#11594)* Update wasm-tools cratesKeeping up to date* Match `bindgen!` world selection with `wit-bindgen::generate!` List of files: /wasmtime-44.0.1/crates/component-macro/src/bindgen.rs

1155d6df - Redesign function configuration in `bindgen!` (#11328)

Mon, 28 Jul 2025 18:31:06 +0000

Redesign function configuration in `bindgen!` (#11328)* Redesign function configuration in `bindgen!`This commit is a redesign of how function-level configuration works inWasmtime's `bindgen!` macro. The main goal of this redesign is tobetter support WASIp3 and component model async functions. Prior to thisredesign there was a mish mash of mechanisms to configure behavior ofimports/exports:* The `async` configuration could turn everything async, nothing async, only some imports async, or everything except some imports async.* The `concurrent_{imports,exports}` keys were required to explicitly opt-in to component model async signatures and applied to all imports/exports.* The `trappable_imports` configuration would indicate a list of imports allowed to trap and it had special configuration for everything, nothing, and only a certain list.* The `tracing` and `verbose_tracing` keys could be applied to either nothing or all functions.Overall the previous state of configuration in `bindgen!` was clearly ahodgepodge of systems that organically grew over time. In my personalopinion it was in dire need of a refresh to take into account howcomponent-model-async ended up being implemented as well asconsolidating the one-off systems amongst all of these configurationkeys. A major motivation of this redesign, for example, was to inheritbehavior from WIT files by default. An `async` function in WIT shouldnot require `concurrent_*` keys to be configured, but rather it shouldgenerate correct bindings by default.In this commit, all of the above keys were removed. All keys have beenreplaced with `imports` and `exports` configuration keys. Each behavesthe same way and looks like so: bindgen!({ // ... imports: { // enable tracing for just this function "my:local/interface/func": tracing, // enable verbose tracing for just this function "my:local/interface/other-func": tracing | verbose_tracing, // this is blocking in WIT, but generate async bindings for // it "my:local/interface/[method]io.block": async, // like above, but use "concurrent" bindings which have // access to the store. "my:local/interface/[method]io.block-again": async | store, // everything else is, by default, trappable default: trappable, }, });Effectively all the function-level configuration items are now bitflags.These bitflags are by default inherited from the WIT files itself (e.g.`async` functions are `async | store` by default). Further configurationis then layered on top at the desires of the embedder. Supported keys are:* `async` - this means that a Rust-level `async` function should be generated. This is either `CallStyle::Async` or `CallStyle::Concurrent` as it was prior, depending on ...* `store` - this means that the generated function will have access to the store on the host. This is only implemented right now for `async | store` functions which map to `CallStyle::Concurrent`. In the future I'd like to support just-`store` functions which means that you could define a synchronous function with access to the store in addition to an asynchronous function.* `trappable` - this means that the function returns a `wasmtime::Result`. If `trappable_errors` is applicable then it means just a `Result` is returned (like before)* `tracing` - this enables `tracing!` integration for this function.* `verbose_tracing` - this logs all argument values for this function (including lists).* `ignore_wit` - this ignores the WIT-level defaults of the function (e.g. ignoring WIT `async`).The way this then works is all modeled is that for any WIT functionbeing generated there are a set of flags associated with that function.To calculate the flags the algorithm looks like:1. Find the first matching rule in the `imports` or `exports` map depending on if the function is imported or exported. If there is no matching rule then use the `default` rule if present. This is the initial set of flags for the function (or empty if nothing was found).2. If `ignore_wit` is present, return the flags from step 1. Otherwise add in `async | store` if the function is `async` in WIT.The resulting set of flags are then used to control how everything isgenerated. For example the same split traits of today are stillgenerated and it's controlled based on the flags. Note though that theprevious `HostConcurrent` trait was renamed to `HostWithStore` to makespace for synchronous functions in this trait in the future too.The end result of all these changes is that configuring imports/exportsnow uses the exact same selection system as the `with` replacement map,meaning there's only one system of selecting functions instead of 3.WIT-level `async` is now respected by default meaning that bindings workby default without further need to configure anything (unless morefunctionality is desired).One final minor change made here as well is that auto-generated`instantiate` methods are now always synchronous and an`instantiate_async` method is unconditionally generated for async mode.This means that bindings always generate both functions and it's up tothe embedder to choose the appropriate one.Closes #11246Closes #11247* Update expanded test expectationsprtest:full* Fix the min platform embedding example* Fix doc tests* Always generate `*WithStore` traitsThis helps when using the `with` mapping since that can always assumethat `HostWithStore` is available in the generated bindings, avoidingthe need to duplicate configuration options.* Update test expectations* Review comments List of files: /wasmtime-44.0.1/crates/component-macro/src/bindgen.rs

703871a2 - Enable the `useless_conversion` Clippy lint (#10838)

Tue, 27 May 2025 16:49:22 +0000

Enable the `useless_conversion` Clippy lint (#10838)* Enable the `useless_conversion` Clippy lintWe've got lots of types in Wasmtime and convert between them quite alot, but often over time conversions become unnecessary throughrefactorings or similar. This will hopefully enable us to clean up someconversions as they come up to try to have as few as possible ideally.* Review comments List of files: /wasmtime-44.0.1/crates/component-macro/src/bindgen.rs

90ac295e - Update Wasmtime to the 2024 Rust Edition (#10806)

Mon, 19 May 2025 16:40:55 +0000

Update Wasmtime to the 2024 Rust Edition (#10806)* Update Wasmtime to the 2024 Rust EditionNow that our MSRV supports the 2024 edition it's possible to make thisswitch. This commit moves Wasmtime to the 2024 Edition to keepup-to-date with Rust idioms and access many of the edition featuresexclusive to the 2024 edition.prtest:full* Reformat with the 2024 edition List of files: /wasmtime-44.0.1/crates/component-macro/src/bindgen.rs

636435f1 - async/stream/future support for wasmtime-wit-bindgen (#10044)

Wed, 22 Jan 2025 17:19:46 +0000

async/stream/future support for wasmtime-wit-bindgen (#10044)* async/stream/future support for wasmtime-wit-bindgenI've split this out of #9582 to make review easier.This patch adds async/stream/future/error-context support to the host bindinggenerator, along with placeholder type and function definitions in the`wasmtime` crate which the generated bindings can refer to. Seehttps://github.com/dicej/rfcs/blob/component-async/accepted/component-model-async.md#componentbindgen-updatesfor the design and rationale.Note that I've added temporary `[patch.crates-io]` overrides in Cargo.toml untilhttps://github.com/bytecodealliance/wit-bindgen/pull/1130 andhttps://github.com/bytecodealliance/wasm-tools/pull/1978 have been released.Also note that we emit a `T: 'static` bound for `AsContextMut` whengenerating bindings with `concurrent_imports: true`. This is only because`rustc` insists that the closure we're passing to`LinkerInstance::func_wrap_concurrent` captures the lifetime of `T` despite mybest efforts to convince it otherwise. Alex and I suspect this is a limitationin the compiler, and I asked about it on the rust-lang Zulip, but we haven'tbeen able to determine a workaround so far.Signed-off-by: Joel Dice remove obsolete TODO commentSigned-off-by: Joel Dice make `futures` dep optionalSigned-off-by: Joel Dice update `wasm-tools` and `wit-bindgen`Signed-off-by: Joel Dice * run cargo vetSigned-off-by: Joel Dice ---------Signed-off-by: Joel Dice List of files: /wasmtime-44.0.1/crates/component-macro/src/bindgen.rs

0e6c711f - Upgrade to wasm-tools 220 and wit-bindgen 0.35 releases (#9601)

Wed, 13 Nov 2024 20:11:38 +0000

Upgrade to wasm-tools 220 and wit-bindgen 0.35 releases (#9601)* component-macro: paths are now an accessor on PackageSourceMap* wast: WastArg enum is now non-exhaustiveand the error messages were mostly written the wrong way around* upgrade to wasm-tools 220 release* supply chain: vet of unicode-width and automatic changes* github actions: upgrade to cargo-vet 0.10.0* wasmtime requires ahash feature on hashbrown, a transitive must have been ticking it prior* upgrade to wit-bindgen 0.35which uses wasm-tools 220, eliminating the duplicate deps in the lockfile.* vet wit-bindgen upgrade* fuzzing: add WasmFeatures::EXTENDED_CONF to expected featureswasm-smith added it in https://github.com/bytecodealliance/wasm-tools/pull/1861 List of files: /wasmtime-44.0.1/crates/component-macro/src/bindgen.rs

c230353d - Configure WIT feature gates at runtime & implement wasi-cli `exit-with-code` (#9381)

Mon, 07 Oct 2024 20:27:14 +0000

Configure WIT feature gates at runtime & implement wasi-cli `exit-with-code` (#9381)* Remove `features` configuration from component::bindgen! and always emit all unstable members. These features will be gated at runtime.* Implement wasi-cli's unstable `exit-with-code`* Add codegen test for unstable features* Add LinkOptions type and add a parameter to all add_to_linker functions in for worlds/interfaces that use any unstable feature.* More descriptive test feature names.* Generate feature gate `if` checks* Expose `cli-exit-with-code` as CLI option* Generate bespoke option types per interface and world.* Add unit test* Remove exit code restriction on Windows* Add cli_exit_with_code test* Use BTreeSet to generate the options in consistent order* Change wasmtime-wasi's `add_to_linker_(a)sync` signature back to how it was and add new variants that take the option parameters.* Lift Windows exit code restriction in tests* Lift Windows exit code restriction List of files: /wasmtime-44.0.1/crates/component-macro/src/bindgen.rs

de8fc46d - bug: bindgen erraneously parses extra comma (#9322)

Sat, 28 Sep 2024 16:28:44 +0000

bug: bindgen erraneously parses extra comma (#9322)Co-authored-by: Lochlan Wansbrough <> List of files: /wasmtime-44.0.1/crates/component-macro/src/bindgen.rs

a13d7823 - feat: component bindgen: add support for multiple wit paths (#9288)

Tue, 24 Sep 2024 17:55:10 +0000

feat: component bindgen: add support for multiple wit paths (#9288)* feat: bindgen: add support for multiple wit paths* expanded tests* fmt---------Co-authored-by: Lochlan Wansbrough <> List of files: /wasmtime-44.0.1/crates/component-macro/src/bindgen.rs

e38ffa19 - wit-bindgen: Don't trace values containing lists by default. (#9262)

Tue, 17 Sep 2024 17:10:37 +0000

wit-bindgen: Don't trace values containing lists by default. (#9262)* wit-bindgen: Don't trace values containing lists by default.`list` values in Wit interfaces can represent things like HTTP bodieswhich can be very large. To enable tracing without spamming logfileswith all this data, put printing of values containing `list`s behinda separate `verbose_tracing` option.This is a coarse-grained approach; but it seems like a pretty gooddefault for tracing, and enabling full tracing when one needs it isstraightforward.In the future, we may want to refine the option by implementingthe `Valuable` trait and using `tracing::field::valuable`, whichcould allow us to do things like print non-`list` fields of recordsthat otherwise contain `list`s.* Use `option_type_contains_lists` more.* Hook up `verbose_tracing` to the macro.* Update expected outputs for tests. List of files: /wasmtime-44.0.1/crates/component-macro/src/bindgen.rs

c8a5acd9 - Update wasm-tools to 215 (#9053)

Fri, 02 Aug 2024 19:29:59 +0000

Update wasm-tools to 215 (#9053)Pulling in some changes notably to multi-package `*.wit` files.prtest:full List of files: /wasmtime-44.0.1/crates/component-macro/src/bindgen.rs

be67ee89 - component-macro: normalize the path parameter in component bindgen (#8871)

Wed, 26 Jun 2024 17:16:46 +0000

component-macro: normalize the path parameter in component bindgen (#8871) List of files: /wasmtime-44.0.1/crates/component-macro/src/bindgen.rs

896e25e3 - upgrade to wasm-tools 0.211.1 (#8838)

Fri, 21 Jun 2024 14:48:21 +0000

upgrade to wasm-tools 0.211.1 (#8838)* upgrade to wasm-tools 0.211.1* code review* cargo vet: auto imports* fuzzing: fix wasm-smith changes* fuzzing: changes for HeapType* Configure features on `Parser` when parsing---------Co-authored-by: Alex Crichton List of files: /wasmtime-44.0.1/crates/component-macro/src/bindgen.rs

44220746 - Overhaul and improve documentation of `bindgen!` (#8727)

Mon, 03 Jun 2024 13:50:05 +0000

Overhaul and improve documentation of `bindgen!` (#8727)This is another take at improving the documentation for `bindgen!` inWasmtime. This commit takes a leaf out of the book ofbytecodealliance/wit-bindgen#871 to organize the documentation of themacro a bit more rather than having one giant doc block that can bedifficult to explore. The macro's documentation itself is now mostly areference of all the options that can be specified. There is now a newdocumentation-only module which serves a few purposes:* Individual examples are organized per-submodule to be a bit more digestable.* Each example has an example of the generated code in addition to the source code used for each example.* All examples are tested on CI to compile (none are run).My hope is that this makes it easier to expand the docs here furtherover time with niche features as they arise or with various options thatthe macro has. This is one of the lynchpins of Wasmtime's support forthe component model so it seems pretty important to have a goodonboarding experience here.Along the way I've implemented a few more niche options for the`bindgen!` macro that I found necessary, such as configuring the`wasmtime` crate and where it's located. List of files: /wasmtime-44.0.1/crates/component-macro/src/bindgen.rs

54d36958 - Always generate the same output structure with `bindgen!` (#8721)

Fri, 31 May 2024 19:53:52 +0000

Always generate the same output structure with `bindgen!` (#8721)Currently with the `bindgen!` macro when the `with` key is used then thegenerated bindings are different than if the `with` key was not used.Not only for replacement purposes but the generated bindings are missingtwo key pieces:* In the generated `add_to_linker` functions bounds and invocations of `with`-overridden interfaces are all missing. This means that the generated `add_to_linker` functions don't actually represent the full world.* The generated module hierarchy has "holes" for all the modules that are overridden. While it's mostly a minor inconvenience it's also easy enough to generate everything via `pub use` to have everything hooked up correctly.After this PR it means that each `bindgen!` macro should, in isolation,work for any other `bindgen!` macro invocation. It shouldn't benecessary to weave things together and remember how each macro wasinvoked along the way. This is primarily to unblock #8715 which isrunning into a case where tcp/udp are generated as sync but theirdependency, `wasi:sockets/network`, is used from an upstream asyncversion. The generated `add_to_linker` does not compile because tcp/udpdepend on `wasi:sockets/network` isn't added to the linker. After fixingthat it then required more modules to be generated, hence this PR. List of files: /wasmtime-44.0.1/crates/component-macro/src/bindgen.rs

34a9ad98 - Update `wit-bindgen`, add `features` to `bindgen!` (#8720)

Fri, 31 May 2024 15:27:40 +0000

Update `wit-bindgen`, add `features` to `bindgen!` (#8720)This commit updates the wit-bindgen family of crates and additionallyadds a `features` key to the `bindgen!` macro. This brings it in linewith `wit-bindgen`'s support which enables usage of the new `@since` and`@unstable` features of WIT. List of files: /wasmtime-44.0.1/crates/component-macro/src/bindgen.rs