feat: support semver aware WIT

Signed-off-by: Victor Adossi <vadossi@cosmonic.com>

Cargo.toml

@@ -37,6 +37,8 @@ strip = true
 anyhow = "1.0.86"
 base64 = "0.22.1"
 heck = "0.5.0"
+log = "0.4.22"
+semver = "1.0.23"
 js-component-bindgen = { path = "./crates/js-component-bindgen" }
 structopt = "0.3.26"
 wasm-encoder = "0.212.0"
@@ -55,4 +57,4 @@ wit-parser = "0.212.0"
 xshell = "0.2.6"
 
 [dev-dependencies]
-anyhow = { workspace = true }
+anyhow = { workspace = true }

crates/js-component-bindgen-component/src/lib.rs

@@ -113,6 +113,20 @@ impl Guest for JsComponentBindgenComponent {
         opts: TypeGenerationOptions,
     ) -> Result<Vec<(String, Vec<u8>)>, String> {
         let mut resolve = Resolve::default();
+
+        // Add features if specified
+        match opts.features {
+            Some(EnabledFeatureSet::List(ref features)) => {
+                for f in features.into_iter() {
+                    resolve.features.insert(f.to_string());
+                }
+            }
+            Some(EnabledFeatureSet::All) => {
+                resolve.all_features = true;
+            }
+            _ => {}
+        }
+
         let ids = match opts.wit {
             Wit::Source(source) => resolve
                 .push_str(format!("{name}.wit"), &source)

crates/js-component-bindgen-component/wit/js-component-bindgen.wit

@@ -73,6 +73,14 @@ world js-component-bindgen {
     path(string),
   }
 
+  /// Enumerate enabled features
+  variant enabled-feature-set {
+    /// Enable only the given list of features
+    %list(list<string>),
+    /// Enable all features
+    all,
+  }
+
   record type-generation-options {
     /// wit to generate typing from
     wit: wit,
@@ -81,6 +89,8 @@ world js-component-bindgen {
     tla-compat: option<bool>,
     instantiation: option<instantiation-mode>,
     map: option<maps>,
+    /// Features that should be enabled as part of feature gating
+    features: option<enabled-feature-set>,
   }
 
   enum export-type {

crates/js-component-bindgen/Cargo.toml

@@ -22,11 +22,13 @@ transpile-bindgen = []
 
 [dependencies]
 anyhow = { workspace = true }
+base64 = { workspace = true }
 heck = { workspace = true }
+log = { workspace = true }
+semver = { workspace = true }
+wasm-encoder = { workspace = true }
 wasmparser = { workspace = true }
 wasmtime-environ = { workspace = true, features = ['component-model'] }
 wit-bindgen-core = { workspace = true }
 wit-component = { workspace = true }
 wit-parser = { workspace = true }
-base64 = { workspace = true }
-wasm-encoder = { workspace = true }

crates/js-component-bindgen/src/lib.rs

@@ -13,14 +13,14 @@ pub use transpile_bindgen::{BindingsMode, InstantiationMode, TranspileOpts};
 use anyhow::Result;
 use transpile_bindgen::transpile_bindgen;
 
-use anyhow::{bail, Context};
+use anyhow::{bail, ensure, Context};
 use wasmtime_environ::component::{ComponentTypesBuilder, Export, StaticModuleIndex};
 use wasmtime_environ::wasmparser::Validator;
 use wasmtime_environ::{PrimaryMap, ScopeVec, Tunables};
 use wit_component::DecodedWasm;
 
 use ts_bindgen::ts_bindgen;
-use wit_parser::{Resolve, Type, TypeDefKind, TypeId, WorldId};
+use wit_parser::{Package, Resolve, Stability, Type, TypeDefKind, TypeId, WorldId};
 
 /// Calls [`write!`] with the passed arguments and unwraps the result.
 ///
@@ -172,3 +172,35 @@ pub fn dealias(resolve: &Resolve, mut id: TypeId) -> TypeId {
         }
     }
 }
+
+/// Check if an item (usually some form of [`WorldItem`]) should be allowed through the feature gate
+/// of a given package.
+fn feature_gate_allowed(
+    resolve: &Resolve,
+    package: &Package,
+    stability: &Stability,
+) -> Result<bool> {
+    let Some(package_version) = package.name.version.as_ref() else {
+        // If the package version is missing (we're likely dealing with an unresolved package)
+        // and we can't really check much.
+        return Ok(true);
+    };
+
+    Ok(match stability {
+        Stability::Unknown => true,
+        Stability::Stable { since, .. } => {
+            ensure!(
+                package_version >= since,
+                "feature gates cannot refer to unreleased (future) package versions"
+            );
+
+            // Stabilization (@since annotation) overrides features and deprecation
+            true
+        }
+        Stability::Unstable { feature } => {
+            // If a @unstable feature is present but the related feature was not enabled
+            // or all features was not selected, exclude
+            resolve.all_features || resolve.features.contains(feature)
+        }
+    })
+}