fix(wasip3): Target-conditional deps

Now when wasm32-wasip3 lands, users can compile with just
`--target wasm32-wasip3`

The cfg alias activates the p3 path AND the wasip3 deps are auto-pulled.

Author: ricochet

.github/workflows/ci.yaml

@@ -55,7 +55,7 @@ jobs:
       run: cargo test -p wstd -p wstd-axum --target wasm32-wasip2 -- --nocapture
 
     - name: wstd tests (wasip3)
-      run: cargo test -p wstd -p wstd-axum --target wasm32-wasip2 --no-default-features --features wasip3 -- --nocapture
+      run: cargo test -p wstd -p wstd-axum --target wasm32-wasip2 --no-default-features --features wasip3,json -- --nocapture
 
     - name: test-programs tests
       run: cargo test -p test-programs -- --nocapture

Cargo.toml

@@ -18,6 +18,9 @@ json = ["dep:serde", "dep:serde_json"]
 wasip2 = ["dep:wasip2"]
 wasip3 = ["dep:wasip3", "dep:wit-bindgen"]
 
+[build-dependencies]
+cfg_aliases = "0.2"
+
 [dependencies]
 anyhow.workspace = true
 async-task.workspace = true
@@ -38,6 +41,12 @@ wstd-macro.workspace = true
 serde = { workspace = true, optional = true }
 serde_json = { workspace = true, optional = true }
 
+# Auto-pull wasip3 deps when targeting wasm32-wasip3 so users don't need
+# to also pass --features wasip3.
+[target.'cfg(all(target_os = "wasi", target_env = "p3"))'.dependencies]
+wasip3 = { workspace = true }
+wit-bindgen = { workspace = true }
+
 [dev-dependencies]
 anyhow.workspace = true
 clap.workspace = true

build.rs

@@ -0,0 +1,13 @@
+use cfg_aliases::cfg_aliases;
+
+fn main() {
+    cfg_aliases! {
+        // True when targeting a wasip3 component, either via the explicit
+        // `wasip3` feature or the `wasm32-wasip3` target (`target_env = "p3"`).
+        wstd_p3: { any(feature = "wasip3", target_env = "p3") },
+        // True when targeting a wasip2 component, either via the `wasip2`
+        // feature (default) or the `wasm32-wasip2` target. wasip3 takes
+        // precedence when both apply.
+        wstd_p2: { all(any(feature = "wasip2", target_env = "p2"), not(wstd_p3)) },
+    }
+}

src/http/body.rs

@@ -8,25 +8,25 @@ use http::header::CONTENT_LENGTH;
 use http_body_util::{BodyExt, combinators::UnsyncBoxBody};
 use std::fmt;
 
-#[cfg(all(feature = "wasip2", not(feature = "wasip3")))]
+#[cfg(wstd_p2)]
 use crate::http::fields::{header_map_from_wasi, header_map_to_wasi};
-#[cfg(all(feature = "wasip2", not(feature = "wasip3")))]
+#[cfg(wstd_p2)]
 use crate::io::AsyncOutputStream;
-#[cfg(all(feature = "wasip2", not(feature = "wasip3")))]
+#[cfg(wstd_p2)]
 use std::future::{Future, poll_fn};
-#[cfg(all(feature = "wasip2", not(feature = "wasip3")))]
+#[cfg(wstd_p2)]
 use std::pin::{Pin, pin};
-#[cfg(all(feature = "wasip2", not(feature = "wasip3")))]
+#[cfg(wstd_p2)]
 use std::task::{Context, Poll};
 
-#[cfg(all(feature = "wasip2", not(feature = "wasip3")))]
+#[cfg(wstd_p2)]
 use crate::runtime::{AsyncPollable, Reactor, WaitFor};
 
-#[cfg(all(feature = "wasip2", not(feature = "wasip3")))]
+#[cfg(wstd_p2)]
 use wasip2::http::types::{
     FutureTrailers, IncomingBody as WasiIncomingBody, OutgoingBody as WasiOutgoingBody,
 };
-#[cfg(all(feature = "wasip2", not(feature = "wasip3")))]
+#[cfg(wstd_p2)]
 use wasip2::io::streams::{InputStream as WasiInputStream, StreamError};
 
 pub mod util {
@@ -70,10 +70,10 @@ enum BodyInner {
     // a boxed http_body::Body impl
     Boxed(UnsyncBoxBody<Bytes, Error>),
     // a body created from a wasi-http incoming-body (p2)
-    #[cfg(all(feature = "wasip2", not(feature = "wasip3")))]
+    #[cfg(wstd_p2)]
     Incoming(Incoming),
     // a body created from a p3 StreamReader
-    #[cfg(feature = "wasip3")]
+    #[cfg(wstd_p3)]
     P3Stream(P3StreamBody),
     // a body in memory
     Complete {
@@ -82,7 +82,7 @@ enum BodyInner {
     },
 }
 
-#[cfg(all(feature = "wasip2", not(feature = "wasip3")))]
+#[cfg(wstd_p2)]
 impl Body {
     pub(crate) async fn send(self, outgoing_body: WasiOutgoingBody) -> Result<(), Error> {
         match self.0 {
@@ -141,7 +141,7 @@ impl Body {
     }
 }
 
-#[cfg(feature = "wasip3")]
+#[cfg(wstd_p3)]
 impl Body {
     pub(crate) fn from_p3_stream(
         reader: wit_bindgen::rt::async_support::StreamReader<u8>,
@@ -161,9 +161,9 @@ impl Body {
             unreachable!()
         }
         match self.0 {
-            #[cfg(all(feature = "wasip2", not(feature = "wasip3")))]
+            #[cfg(wstd_p2)]
             BodyInner::Incoming(i) => i.into_http_body().boxed_unsync(),
-            #[cfg(feature = "wasip3")]
+            #[cfg(wstd_p3)]
             BodyInner::P3Stream(p3) => {
                 // Convert p3 stream body to a boxed body
                 let stream = AsyncInputStream::new(p3.reader.unwrap());
@@ -198,7 +198,7 @@ impl Body {
                 // For p3 streams, read directly using the async read method
                 // instead of going through poll_next (which doesn't properly
                 // persist the read future across polls, causing hangs).
-                #[cfg(feature = "wasip3")]
+                #[cfg(wstd_p3)]
                 if let BodyInner::P3Stream(p3) = prev {
                     let mut stream = AsyncInputStream::new(p3.reader.unwrap());
                     let mut all_data = Vec::new();
@@ -221,11 +221,11 @@ impl Body {
                 }
 
                 let boxed_body = match prev {
-                    #[cfg(all(feature = "wasip2", not(feature = "wasip3")))]
+                    #[cfg(wstd_p2)]
                     BodyInner::Incoming(i) => i.into_http_body().boxed_unsync(),
                     BodyInner::Boxed(b) => b,
                     BodyInner::Complete { .. } => unreachable!(),
-                    #[cfg(feature = "wasip3")]
+                    #[cfg(wstd_p3)]
                     BodyInner::P3Stream(_) => unreachable!(),
                 };
                 let collected = boxed_body.collect().await?;
@@ -251,9 +251,9 @@ impl Body {
         match &self.0 {
             BodyInner::Boxed(b) => b.size_hint().exact(),
             BodyInner::Complete { data, .. } => Some(data.len() as u64),
-            #[cfg(all(feature = "wasip2", not(feature = "wasip3")))]
+            #[cfg(wstd_p2)]
             BodyInner::Incoming(i) => i.size_hint.content_length(),
-            #[cfg(feature = "wasip3")]
+            #[cfg(wstd_p3)]
             BodyInner::P3Stream(p3) => p3.size_hint.content_length(),
         }
     }
@@ -426,28 +426,27 @@ impl fmt::Display for InvalidContentLength {
 }
 impl std::error::Error for InvalidContentLength {}
 
-#[cfg(feature = "wasip3")]
+#[cfg(wstd_p3)]
 struct P3StreamBody {
     reader: Option<wit_bindgen::rt::async_support::StreamReader<u8>>,
     size_hint: BodyHint,
 }
 
-#[cfg(feature = "wasip3")]
+#[cfg(wstd_p3)]
 impl fmt::Debug for P3StreamBody {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         f.debug_struct("P3StreamBody").finish()
     }
 }
 
-
-#[cfg(all(feature = "wasip2", not(feature = "wasip3")))]
+#[cfg(wstd_p2)]
 #[derive(Debug)]
 struct Incoming {
     body: WasiIncomingBody,
     size_hint: BodyHint,
 }
 
-#[cfg(all(feature = "wasip2", not(feature = "wasip3")))]
+#[cfg(wstd_p2)]
 impl Incoming {
     fn into_http_body(self) -> IncomingBody {
         IncomingBody::new(self.body, self.size_hint)
@@ -482,14 +481,14 @@ impl Incoming {
     }
 }
 
-#[cfg(all(feature = "wasip2", not(feature = "wasip3")))]
+#[cfg(wstd_p2)]
 #[derive(Debug)]
 pub struct IncomingBody {
     state: Option<Pin<Box<IncomingBodyState>>>,
     size_hint: BodyHint,
 }
 
-#[cfg(all(feature = "wasip2", not(feature = "wasip3")))]
+#[cfg(wstd_p2)]
 impl IncomingBody {
     fn new(body: WasiIncomingBody, size_hint: BodyHint) -> Self {
         Self {
@@ -508,7 +507,7 @@ impl IncomingBody {
     }
 }
 
-#[cfg(all(feature = "wasip2", not(feature = "wasip3")))]
+#[cfg(wstd_p2)]
 impl HttpBody for IncomingBody {
     type Data = Bytes;
     type Error = Error;
@@ -564,7 +563,7 @@ impl HttpBody for IncomingBody {
     }
 }
 
-#[cfg(all(feature = "wasip2", not(feature = "wasip3")))]
+#[cfg(wstd_p2)]
 pin_project_lite::pin_project! {
     #[project = IBSProj]
     #[derive(Debug)]
@@ -583,18 +582,18 @@ pin_project_lite::pin_project! {
     }
 }
 
-#[cfg(all(feature = "wasip2", not(feature = "wasip3")))]
+#[cfg(wstd_p2)]
 #[derive(Debug)]
 struct BodyState {
     wait: Option<Pin<Box<WaitFor>>>,
     subscription: Option<AsyncPollable>,
     stream: WasiInputStream,
 }
 
-#[cfg(all(feature = "wasip2", not(feature = "wasip3")))]
+#[cfg(wstd_p2)]
 const MAX_FRAME_SIZE: u64 = 64 * 1024;
 
-#[cfg(all(feature = "wasip2", not(feature = "wasip3")))]
+#[cfg(wstd_p2)]
 impl BodyState {
     fn poll_frame(
         mut self: Pin<&mut Self>,
@@ -639,15 +638,15 @@ impl BodyState {
     }
 }
 
-#[cfg(all(feature = "wasip2", not(feature = "wasip3")))]
+#[cfg(wstd_p2)]
 #[derive(Debug)]
 struct TrailersState {
     wait: Option<Pin<Box<WaitFor>>>,
     subscription: Option<AsyncPollable>,
     future_trailers: FutureTrailers,
 }
 
-#[cfg(all(feature = "wasip2", not(feature = "wasip3")))]
+#[cfg(wstd_p2)]
 impl TrailersState {
     fn new(future_trailers: FutureTrailers) -> Self {
         Self {

src/http/client.rs

@@ -20,7 +20,7 @@ impl Client {
     }
 
     /// Send an HTTP request.
-    #[cfg(all(feature = "wasip2", not(feature = "wasip3")))]
+    #[cfg(wstd_p2)]
     pub async fn send<B: Into<Body>>(&self, req: Request<B>) -> Result<Response<Body>, Error> {
         use crate::http::request::try_into_outgoing;
         use crate::http::response::try_from_incoming;
@@ -42,7 +42,7 @@ impl Client {
     }
 
     /// Send an HTTP request.
-    #[cfg(feature = "wasip3")]
+    #[cfg(wstd_p3)]
     pub async fn send<B: Into<Body>>(&self, req: Request<B>) -> Result<Response<Body>, Error> {
         use crate::http::request::try_into_wasi_request;
         use crate::http::response::try_from_wasi_response;
@@ -97,7 +97,7 @@ impl Client {
         }
     }
 
-    #[cfg(all(feature = "wasip2", not(feature = "wasip3")))]
+    #[cfg(wstd_p2)]
     fn wasi_options_p2(
         &self,
     ) -> Result<Option<wasip2::http::types::RequestOptions>, crate::http::Error> {
@@ -108,7 +108,7 @@ impl Client {
     }
 }
 
-#[cfg(feature = "wasip3")]
+#[cfg(wstd_p3)]
 pub(crate) type P3RequestOptions = RequestOptions;
 
 #[derive(Default, Debug, Clone)]
@@ -119,7 +119,7 @@ pub(crate) struct RequestOptions {
 }
 
 impl RequestOptions {
-    #[cfg(all(feature = "wasip2", not(feature = "wasip3")))]
+    #[cfg(wstd_p2)]
     fn to_wasi_p2(&self) -> Result<wasip2::http::types::RequestOptions, crate::http::Error> {
         let wasi = wasip2::http::types::RequestOptions::new();
         if let Some(timeout) = self.connect_timeout {

src/http/error.rs

@@ -7,10 +7,10 @@ pub use anyhow::Context;
 pub use http::header::{InvalidHeaderName, InvalidHeaderValue};
 pub use http::method::InvalidMethod;
 
-#[cfg(all(feature = "wasip2", not(feature = "wasip3")))]
+#[cfg(wstd_p2)]
 pub use wasip2::http::types::{ErrorCode, HeaderError};
 
-#[cfg(feature = "wasip3")]
+#[cfg(wstd_p3)]
 pub use wasip3::http::types::{ErrorCode, HeaderError};
 
 pub type Error = anyhow::Error;

src/http/fields.rs

@@ -2,13 +2,13 @@ pub use http::header::{HeaderMap, HeaderName, HeaderValue};
 
 use super::{Error, error::Context};
 
-#[cfg(all(feature = "wasip2", not(feature = "wasip3")))]
+#[cfg(wstd_p2)]
 use wasip2::http::types::Fields;
 
-#[cfg(feature = "wasip3")]
+#[cfg(wstd_p3)]
 use wasip3::http::types::Fields;
 
-#[cfg(all(feature = "wasip2", not(feature = "wasip3")))]
+#[cfg(wstd_p2)]
 pub(crate) fn header_map_from_wasi(wasi_fields: Fields) -> Result<HeaderMap, Error> {
     let mut output = HeaderMap::new();
     for (key, value) in wasi_fields.entries() {
@@ -21,7 +21,7 @@ pub(crate) fn header_map_from_wasi(wasi_fields: Fields) -> Result<HeaderMap, Err
     Ok(output)
 }
 
-#[cfg(feature = "wasip3")]
+#[cfg(wstd_p3)]
 pub(crate) fn header_map_from_wasi(wasi_fields: Fields) -> Result<HeaderMap, Error> {
     let mut output = HeaderMap::new();
     for (key, value) in wasi_fields.copy_all() {

src/http/method.rs

@@ -1,7 +1,7 @@
-#[cfg(all(feature = "wasip2", not(feature = "wasip3")))]
+#[cfg(wstd_p2)]
 use wasip2::http::types::Method as WasiMethod;
 
-#[cfg(feature = "wasip3")]
+#[cfg(wstd_p3)]
 use wasip3::http::types::Method as WasiMethod;
 
 pub use http::Method;

src/http/mod.rs

@@ -27,11 +27,12 @@ pub mod server;
 // Conditionally-compiled declarative macro for HTTP server export
 //
 // The `#[wstd::http_server]` proc macro delegates to this declarative macro.
-// Because `#[macro_export]` macros are compiled in wstd's context, the `cfg`
-// checks here use wstd's own feature flags so consumers don't need to define
-// `wasip2`/`wasip3` features themselves.
+// Because `#[macro_export]` macros are compiled in wstd's context, the
+// `wstd_p2` / `wstd_p3` cfg aliases (defined in build.rs) are evaluated against
+// wstd's own features and target environment. Consumers don't need to define
+// any features themselves.
 
-#[cfg(all(feature = "wasip2", not(feature = "wasip3")))]
+#[cfg(wstd_p2)]
 #[macro_export]
 #[doc(hidden)]
 macro_rules! __http_server_export {
@@ -91,7 +92,7 @@ macro_rules! __http_server_export {
     };
 }
 
-#[cfg(feature = "wasip3")]
+#[cfg(wstd_p3)]
 #[macro_export]
 #[doc(hidden)]
 macro_rules! __http_server_export {