Result alias for convienient use of anyhow::Error without depending on anyhow (#5853)

* Add a Result type alias

* Refer to the type in top-level docs

* Use this inside the documentation for the bindgen! macro

* Fix tests

* Address small PR feedback

* Simply re-export anyhow types

crates/fuzzing/src/oracles.rs

@@ -785,7 +785,6 @@ pub fn set_fuel<T>(store: &mut Store<T>, fuel: u64) {
 /// arbitrary types and values.
 pub fn dynamic_component_api_target(input: &mut arbitrary::Unstructured) -> arbitrary::Result<()> {
     use crate::generators::component_types;
-    use anyhow::Result;
     use component_fuzz_util::{TestCase, EXPORT_FUNCTION, IMPORT_FUNCTION};
     use component_test_util::FuncExt;
     use wasmtime::component::{Component, Linker, Val};

crates/wasmtime/src/component/mod.rs

@@ -82,7 +82,6 @@ pub(crate) use self::store::ComponentStoreData;
 /// Then you can interact with the generated bindings like so:
 ///
 /// ```rust,ignore
-/// use anyhow::Result;
 /// use wasmtime::component::*;
 /// use wasmtime::{Config, Engine, Store};
 ///
@@ -97,12 +96,12 @@ pub(crate) use self::store::ComponentStoreData;
 /// impl HelloWorldImports for MyState {
 ///     // Note the `Result` return value here where `Ok` is returned back to
 ///     // the component and `Err` will raise a trap.
-///     fn name(&mut self) -> Result<String> {
+///     fn name(&mut self) -> wasmtime::Result<String> {
 ///         Ok(self.name.clone())
 ///     }
 /// }
 ///
-/// fn main() -> Result<()> {
+/// fn main() -> wasmtime::Result<()> {
 ///     // Configure an `Engine` and compile the `Component` that is being run for
 ///     // the application.
 ///     let mut config = Config::new();
@@ -168,7 +167,6 @@ pub(crate) use self::store::ComponentStoreData;
 /// Then you can interact with the generated bindings like so:
 ///
 /// ```rust,ignore
-/// use anyhow::Result;
 /// use wasmtime::component::*;
 /// use wasmtime::{Config, Engine, Store};
 ///
@@ -180,16 +178,16 @@ pub(crate) use self::store::ComponentStoreData;
 ///
 /// // Note that the trait here is per-interface and within a submodule now.
 /// impl host::Host for MyState {
-///     fn gen_random_integer(&mut self) -> Result<u32> {
+///     fn gen_random_integer(&mut self) -> wasmtime::Result<u32> {
 ///         Ok(rand::thread_rng().gen())
 ///     }
 ///
-///     fn sha256(&mut self, bytes: Vec<u8>) -> Result<String> {
+///     fn sha256(&mut self, bytes: Vec<u8>) -> wasmtime::Result<String> {
 ///         // ...
 ///     }
 /// }
 ///
-/// fn main() -> Result<()> {
+/// fn main() -> wasmtime::Result<()> {
 ///     let mut config = Config::new();
 ///     config.wasm_component_model(true);
 ///     let engine = Engine::new(&config)?;

crates/wasmtime/src/lib.rs

@@ -27,10 +27,9 @@
 //! An example of using Wasmtime looks like:
 //!
 //! ```
-//! use anyhow::Result;
 //! use wasmtime::*;
 //!
-//! fn main() -> Result<()> {
+//! fn main() -> wasmtime::Result<()> {
 //!     // Modules can be compiled through either the text or binary format
 //!     let engine = Engine::default();
 //!     let wat = r#"
@@ -141,10 +140,9 @@
 //! For example we can reimplement the above example with a `Linker`:
 //!
 //! ```
-//! use anyhow::Result;
 //! use wasmtime::*;
 //!
-//! fn main() -> Result<()> {
+//! fn main() -> wasmtime::Result<()> {
 //!     let engine = Engine::default();
 //!     let wat = r#"
 //!         (module
@@ -301,11 +299,10 @@
 //! An example of using WASI looks like:
 //!
 //! ```no_run
-//! # use anyhow::Result;
 //! # use wasmtime::*;
 //! use wasmtime_wasi::sync::WasiCtxBuilder;
 //!
-//! # fn main() -> Result<()> {
+//! # fn main() -> wasmtime::Result<()> {
 //! // Compile our module and create a `Linker` which has WASI functions defined
 //! // within it.
 //! let engine = Engine::default();
@@ -333,7 +330,7 @@
 //! use std::str;
 //!
 //! # use wasmtime::*;
-//! # fn main() -> anyhow::Result<()> {
+//! # fn main() -> wasmtime::Result<()> {
 //! let mut store = Store::default();
 //! let log_str = Func::wrap(&mut store, |mut caller: Caller<'_, ()>, ptr: i32, len: i32| {
 //!     // Use our `caller` context to learn about the memory export of the
@@ -427,6 +424,13 @@ pub use crate::trap::*;
 pub use crate::types::*;
 pub use crate::values::*;
 
+/// A convenience wrapper for `Result<T, anyhow::Error>`.
+///
+/// This type can be used to interact with `wasmtimes`'s extensive use
+/// of `anyhow::Error` while still not directly depending on `anyhow`.
+/// This type alias is identical to `anyhow::Result`.
+pub use anyhow::{Error, Result};
+
 #[cfg(feature = "component-model")]
 pub mod component;
 

crates/wit-bindgen/src/lib.rs

@@ -179,7 +179,7 @@ impl Wasmtime {
                     "
                         pub fn new(
                             __exports: &mut wasmtime::component::ExportInstance<'_, '_>,
-                        ) -> anyhow::Result<{camel}> {{
+                        ) -> wasmtime::Result<{camel}> {{
                     "
                 );
                 let mut fields = Vec::new();
@@ -267,7 +267,7 @@ impl Wasmtime {
                     mut store: impl wasmtime::AsContextMut<Data = T>,
                     component: &wasmtime::component::Component,
                     linker: &wasmtime::component::Linker<T>,
-                ) -> anyhow::Result<(Self, wasmtime::component::Instance)> {{
+                ) -> wasmtime::Result<(Self, wasmtime::component::Instance)> {{
                     let instance = linker.instantiate{async__}(&mut store, component){await_}?;
                     Ok((Self::new(store, &instance)?, instance))
                 }}
@@ -278,7 +278,7 @@ impl Wasmtime {
                 pub {async_} fn instantiate_pre<T {send}>(
                     mut store: impl wasmtime::AsContextMut<Data = T>,
                     instance_pre: &wasmtime::component::InstancePre<T>,
-                ) -> anyhow::Result<(Self, wasmtime::component::Instance)> {{
+                ) -> wasmtime::Result<(Self, wasmtime::component::Instance)> {{
                     let instance = instance_pre.instantiate{async__}(&mut store){await_}?;
                     Ok((Self::new(store, &instance)?, instance))
                 }}
@@ -294,7 +294,7 @@ impl Wasmtime {
                 pub fn new(
                     mut store: impl wasmtime::AsContextMut,
                     instance: &wasmtime::component::Instance,
-                ) -> anyhow::Result<Self> {{
+                ) -> wasmtime::Result<Self> {{
                     let mut store = store.as_context_mut();
                     let mut exports = instance.exports(&mut store);
                     let mut __exports = exports.root();
@@ -397,7 +397,7 @@ impl Wasmtime {
                 pub fn add_to_linker<T, U>(
                     linker: &mut wasmtime::component::Linker<T>,
                     get: impl Fn(&mut T) -> &mut U + Send + Sync + Copy + 'static,
-                ) -> anyhow::Result<()>
+                ) -> wasmtime::Result<()>
                     where U: \
             "
         );
@@ -442,7 +442,7 @@ impl Wasmtime {
                 pub fn add_root_to_linker<T, U>(
                     linker: &mut wasmtime::component::Linker<T>,
                     get: impl Fn(&mut T) -> &mut U + Send + Sync + Copy + 'static,
-                ) -> anyhow::Result<()>
+                ) -> wasmtime::Result<()>
                     where U: {world_trait}{maybe_send}
                 {{
                     let mut linker = linker.root();
@@ -978,7 +978,7 @@ impl<'a> InterfaceGenerator<'a> {
                 pub fn add_to_linker<T, U>(
                     linker: &mut wasmtime::component::Linker<T>,
                     get: impl Fn(&mut T) -> &mut U + Send + Sync + Copy + 'static,
-                ) -> anyhow::Result<()>
+                ) -> wasmtime::Result<()>
                     where {where_clause},
                 {{
             "
@@ -1124,9 +1124,9 @@ impl<'a> InterfaceGenerator<'a> {
             self.push_str(&error_typename);
             self.push_str(">");
         } else {
-            // All other functions get their return values wrapped in an anyhow::Result.
+            // All other functions get their return values wrapped in an wasmtime::Result.
             // Returning the anyhow::Error case can be used to trap.
-            self.push_str("anyhow::Result<");
+            self.push_str("wasmtime::Result<");
             self.print_result_ty(&func.results, TypeMode::Owned);
             self.push_str(">");
         }
@@ -1174,7 +1174,7 @@ impl<'a> InterfaceGenerator<'a> {
             self.print_ty(&param.1, TypeMode::AllBorrowed("'_"));
             self.push_str(",");
         }
-        self.src.push_str(") -> anyhow::Result<");
+        self.src.push_str(") -> wasmtime::Result<");
         self.print_result_ty(&func.results, TypeMode::Owned);
 
         if self.gen.opts.async_ {

tests/all/memory_creator.rs

@@ -57,7 +57,7 @@ mod not_for_windows {
             Some(self.size - self.guard_size)
         }
 
-        fn grow_to(&mut self, new_size: usize) -> Result<(), anyhow::Error> {
+        fn grow_to(&mut self, new_size: usize) -> wasmtime::Result<()> {
             println!("grow to {:x}", new_size);
             let delta = new_size - self.used_wasm_bytes;
             unsafe {