Respect build target from cargo config

src/lib.rs

@@ -188,14 +188,20 @@ pub async fn run_cargo_command(
     }
     cargo.args(args);
 
-    // TODO: consider targets from .cargo/config.toml
+    let cargo_config = cargo_config2::Config::load()?;
 
     // Handle the target for buildable commands
     if command.buildable() {
         install_wasm32_wasip1(config)?;
 
         // Add an implicit wasm32-wasip1 target if there isn't a wasm target present
-        if !cargo_args.targets.iter().any(|t| is_wasm_target(t)) {
+        if !cargo_args.targets.iter().any(|t| is_wasm_target(t))
+            && !cargo_config
+                .build
+                .target
+                .as_ref()
+                .is_some_and(|v| v.iter().any(|t| is_wasm_target(t.triple())))
+        {
             cargo.arg("--target").arg("wasm32-wasip1");
         }
 
@@ -235,7 +241,7 @@ pub async fn run_cargo_command(
     }
 
     let runner = if needs_runner && command.runnable() {
-        Some(get_runner(command == CargoCommand::Serve)?)
+        Some(get_runner(&cargo_config, command == CargoCommand::Serve)?)
     } else {
         None
     };
@@ -259,9 +265,7 @@ pub async fn run_cargo_command(
     Ok(outputs.into_iter().map(|o| o.path).collect())
 }
 
-fn get_runner(serve: bool) -> Result<PathAndArgs> {
-    let cargo_config = cargo_config2::Config::load()?;
-
+fn get_runner(cargo_config: &cargo_config2::Config, serve: bool) -> Result<PathAndArgs> {
     // We check here before we actually build that a runtime is present.
     // We first check the runner for `wasm32-wasip1` in the order from
     // cargo's convention for a user-supplied runtime (path or executable)

tests/build.rs

@@ -160,7 +160,7 @@ fn it_adds_a_producers_field() -> Result<()> {
 }
 
 #[test]
-fn it_builds_wasm32_unknown_unknown() -> Result<()> {
+fn it_builds_wasm32_unknown_unknown_from_cli() -> Result<()> {
     let project = Project::new("foo")?;
 
     project
@@ -182,6 +182,60 @@ fn it_builds_wasm32_unknown_unknown() -> Result<()> {
     Ok(())
 }
 
+#[test]
+fn it_builds_wasm32_unknown_unknown_from_config() -> Result<()> {
+    let project = Project::new("foo")?;
+
+    project.file(
+        ".cargo/config.toml",
+        r#"[build]
+target = "wasm32-unknown-unknown"
+    "#,
+    )?;
+
+    project
+        .cargo_component("build")
+        .assert()
+        .stderr(contains(
+            "Finished `dev` profile [unoptimized + debuginfo] target(s)",
+        ))
+        .success();
+
+    validate_component(
+        &project
+            .build_dir()
+            .join("wasm32-unknown-unknown")
+            .join("debug")
+            .join("foo.wasm"),
+    )?;
+
+    Ok(())
+}
+
+#[test]
+fn it_builds_wasm32_unknown_unknown_from_env() -> Result<()> {
+    let project = Project::new("foo")?;
+
+    project
+        .cargo_component("build")
+        .env("CARGO_BUILD_TARGET", "wasm32-unknown-unknown")
+        .assert()
+        .stderr(contains(
+            "Finished `dev` profile [unoptimized + debuginfo] target(s)",
+        ))
+        .success();
+
+    validate_component(
+        &project
+            .build_dir()
+            .join("wasm32-unknown-unknown")
+            .join("debug")
+            .join("foo.wasm"),
+    )?;
+
+    Ok(())
+}
+
 #[test]
 fn it_regenerates_target_if_wit_changed() -> Result<()> {
     let project = Project::new("foo")?;