fix: use generated binary path from cargo instead

Previously when we'd invoke wasm-bindgen we'd assume that the binary we wanted
to process was `target/wasm32-unknown-unknown{debug|release}/crate.wasm`, which
isn't the case for all flags that Cargo accepts.

src/bindgen.rs

@@ -21,30 +21,10 @@ pub fn wasm_bindgen_build(
     reference_types: bool,
     target: Target,
     profile: BuildProfile,
-    extra_options: &Vec<String>,
+    wasm_path: &Path,
 ) -> Result<()> {
-    let release_or_debug = match profile {
-        BuildProfile::Release | BuildProfile::Profiling => "release",
-        BuildProfile::Dev => "debug",
-    };
-
     let out_dir = out_dir.to_str().unwrap();
 
-    let target_directory = {
-        let mut has_target_dir_iter = extra_options.iter();
-        has_target_dir_iter
-            .find(|&it| it == "--target-dir")
-            .and_then(|_| has_target_dir_iter.next())
-            .map(Path::new)
-            .unwrap_or(data.target_directory())
-    };
-
-    let wasm_path = target_directory
-        .join("wasm32-unknown-unknown")
-        .join(release_or_debug)
-        .join(data.crate_name())
-        .with_extension("wasm");
-
     let dts_arg = if disable_dts {
         "--no-typescript"
     } else {

src/build/mod.rs

@@ -6,8 +6,10 @@ use crate::emoji;
 use crate::manifest::Crate;
 use crate::PBAR;
 use anyhow::{anyhow, bail, Context, Result};
-use std::path::Path;
-use std::process::Command;
+use cargo_metadata::Message;
+use std::io::BufReader;
+use std::path::{Path, PathBuf};
+use std::process::{Command, Stdio};
 use std::str;
 
 pub mod wasm_target;
@@ -77,12 +79,16 @@ pub fn cargo_build_wasm(
     path: &Path,
     profile: BuildProfile,
     extra_options: &[String],
-) -> Result<()> {
+) -> Result<PathBuf> {
     let msg = format!("{}Compiling to Wasm...", emoji::CYCLONE);
     PBAR.info(&msg);
 
     let mut cmd = Command::new("cargo");
-    cmd.current_dir(path).arg("build").arg("--lib");
+    cmd.current_dir(path)
+        .stdout(Stdio::piped())
+        .arg("build")
+        .arg("--lib")
+        .arg("--message-format=json-render-diagnostics");
 
     if PBAR.quiet() {
         cmd.arg("--quiet");
@@ -129,8 +135,36 @@ pub fn cargo_build_wasm(
         .collect::<Result<Vec<_>>>()?;
     cmd.args(extra_options_with_absolute_paths);
 
-    child::run(cmd, "cargo build").context("Compiling your crate to WebAssembly failed")?;
-    Ok(())
+    let mut last_artifact = None;
+
+    child::run_with_handler(cmd, "cargo build", |child| {
+        let stdout = child.stdout.take().unwrap();
+        let reader = BufReader::new(stdout);
+
+        for message in cargo_metadata::Message::parse_stream(reader) {
+            match message? {
+                Message::CompilerArtifact(artifact) => last_artifact = Some(artifact),
+                Message::CompilerMessage(msg) => {
+                    if let Some(rendered) = msg.message.rendered {
+                        println!("{}", rendered);
+                    }
+                }
+                _ => (),
+            }
+        }
+
+        Ok(())
+    })
+    .context("Compiling your crate to WebAssembly failed")?;
+
+    let last_artifact = last_artifact
+        .ok_or_else(|| anyhow!("No artifacts were generated by cargo build"))?
+        .filenames
+        .into_iter()
+        .next()
+        .ok_or_else(|| anyhow!("No artifact filenames were generated by cargo build"))?;
+
+    Ok(PathBuf::from(last_artifact))
 }
 
 /// Runs `cargo build --tests` targeting `wasm32-unknown-unknown`.

src/child.rs

@@ -6,7 +6,7 @@
 use crate::install::Tool;
 use anyhow::{bail, Result};
 use log::info;
-use std::process::{Command, Stdio};
+use std::process::{Child, Command, Stdio};
 
 /// Return a new Command object
 pub fn new_command(program: &str) -> Command {
@@ -62,3 +62,29 @@ pub fn run_capture_stdout(mut command: Command, command_name: &Tool) -> Result<S
         )
     }
 }
+
+/// Run the command and handle child, return on success.
+pub fn run_with_handler<T>(
+    mut command: Command,
+    command_name: &str,
+    handle: impl FnOnce(&mut Child) -> Result<T>,
+) -> Result<T> {
+    info!("Running {:?}", command);
+
+    let mut child = command.spawn()?;
+
+    let ret = handle(&mut child)?;
+
+    let status = child.wait()?;
+
+    if status.success() {
+        Ok(ret)
+    } else {
+        bail!(
+            "failed to execute `{}`: exited with {}\n  full command: {:?}",
+            command_name,
+            status,
+            command,
+        )
+    }
+}

src/command/build.rs

@@ -203,7 +203,13 @@ impl Default for BuildOptions {
     }
 }
 
-type BuildStep = fn(&mut Build) -> Result<()>;
+type BuildStep = fn(&mut Build, _state: &mut State) -> Result<()>;
+
+#[derive(Default)]
+struct State {
+    // step state
+    cargo_artifact: Option<PathBuf>,
+}
 
 impl Build {
     /// Construct a build command from the given options.
@@ -260,9 +266,10 @@ impl Build {
         let process_steps = Build::get_process_steps(self.mode, self.no_pack, self.no_opt);
 
         let started = Instant::now();
+        let mut state = State::default();
 
         for (_, process_step) in process_steps {
-            process_step(self)?;
+            process_step(self, &mut state)?;
         }
 
         let duration = crate::command::utils::elapsed(started.elapsed());
@@ -331,51 +338,48 @@ impl Build {
         steps
     }
 
-    fn step_check_rustc_version(&mut self) -> Result<()> {
+    fn step_check_rustc_version(&mut self, _state: &mut State) -> Result<()> {
         info!("Checking rustc version...");
         let version = build::check_rustc_version()?;
         let msg = format!("rustc version is {}.", version);
         info!("{}", &msg);
         Ok(())
     }
 
-    fn step_check_crate_config(&mut self) -> Result<()> {
+    fn step_check_crate_config(&mut self, _state: &mut State) -> Result<()> {
         info!("Checking crate configuration...");
         self.crate_data.check_crate_config()?;
         info!("Crate is correctly configured.");
         Ok(())
     }
 
-    fn step_check_for_wasm_target(&mut self) -> Result<()> {
+    fn step_check_for_wasm_target(&mut self, _state: &mut State) -> Result<()> {
         info!("Checking for wasm-target...");
         build::wasm_target::check_for_wasm32_target()?;
         info!("Checking for wasm-target was successful.");
         Ok(())
     }
 
-    fn step_build_wasm(&mut self) -> Result<()> {
+    fn step_build_wasm(&mut self, state: &mut State) -> Result<()> {
         info!("Building wasm...");
-        build::cargo_build_wasm(&self.crate_path, self.profile, &self.extra_options)?;
+        let cargo_artifact =
+            build::cargo_build_wasm(&self.crate_path, self.profile, &self.extra_options)?;
+
+        info!("wasm built at {:#?}.", cargo_artifact);
+
+        state.cargo_artifact = Some(cargo_artifact);
 
-        info!(
-            "wasm built at {:#?}.",
-            &self
-                .crate_path
-                .join("target")
-                .join("wasm32-unknown-unknown")
-                .join("release")
-        );
         Ok(())
     }
 
-    fn step_create_dir(&mut self) -> Result<()> {
+    fn step_create_dir(&mut self, _state: &mut State) -> Result<()> {
         info!("Creating a pkg directory...");
         create_pkg_dir(&self.out_dir)?;
         info!("Created a pkg directory at {:#?}.", &self.crate_path);
         Ok(())
     }
 
-    fn step_create_json(&mut self) -> Result<()> {
+    fn step_create_json(&mut self, _state: &mut State) -> Result<()> {
         self.crate_data.write_package_json(
             &self.out_dir,
             &self.scope,
@@ -389,21 +393,21 @@ impl Build {
         Ok(())
     }
 
-    fn step_copy_readme(&mut self) -> Result<()> {
+    fn step_copy_readme(&mut self, _state: &mut State) -> Result<()> {
         info!("Copying readme from crate...");
         readme::copy_from_crate(&self.crate_data, &self.crate_path, &self.out_dir)?;
         info!("Copied readme from crate to {:#?}.", &self.out_dir);
         Ok(())
     }
 
-    fn step_copy_license(&mut self) -> Result<()> {
+    fn step_copy_license(&mut self, _state: &mut State) -> Result<()> {
         info!("Copying license from crate...");
         license::copy_from_crate(&self.crate_data, &self.crate_path, &self.out_dir)?;
         info!("Copied license from crate to {:#?}.", &self.out_dir);
         Ok(())
     }
 
-    fn step_install_wasm_bindgen(&mut self) -> Result<()> {
+    fn step_install_wasm_bindgen(&mut self, _state: &mut State) -> Result<()> {
         info!("Identifying wasm-bindgen dependency...");
         let lockfile = Lockfile::new(&self.crate_data)?;
         let bindgen_version = lockfile.require_wasm_bindgen()?;
@@ -419,7 +423,7 @@ impl Build {
         Ok(())
     }
 
-    fn step_run_wasm_bindgen(&mut self) -> Result<()> {
+    fn step_run_wasm_bindgen(&mut self, state: &mut State) -> Result<()> {
         info!("Building the wasm bindings...");
         bindgen::wasm_bindgen_build(
             &self.crate_data,
@@ -431,13 +435,16 @@ impl Build {
             self.reference_types,
             self.target,
             self.profile,
-            &self.extra_options,
+            state
+                .cargo_artifact
+                .as_ref()
+                .expect("bindgen ran before cargo build"),
         )?;
         info!("wasm bindings were built at {:#?}.", &self.out_dir);
         Ok(())
     }
 
-    fn step_run_wasm_opt(&mut self) -> Result<()> {
+    fn step_run_wasm_opt(&mut self, _state: &mut State) -> Result<()> {
         let mut args = match self
             .crate_data
             .configured_profile(self.profile)