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

@@ -41,6 +41,8 @@ pub struct Build {
     pub bindgen: Option<install::Status>,
     pub cache: Cache,
     pub extra_options: Vec<String>,
+    // step state
+    cargo_artifact: Option<PathBuf>,
 }
 
 /// What sort of output we're going to be generating and flags we're invoking
@@ -247,6 +249,7 @@ impl Build {
             bindgen: None,
             cache: cache::get_wasm_pack_cache()?,
             extra_options: build_opts.extra_options,
+            cargo_artifact: None,
         })
     }
 
@@ -355,16 +358,13 @@ impl Build {
 
     fn step_build_wasm(&mut self) -> 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);
+
+        self.cargo_artifact = Some(cargo_artifact);
 
-        info!(
-            "wasm built at {:#?}.",
-            &self
-                .crate_path
-                .join("target")
-                .join("wasm32-unknown-unknown")
-                .join("release")
-        );
         Ok(())
     }
 
@@ -431,7 +431,9 @@ impl Build {
             self.reference_types,
             self.target,
             self.profile,
-            &self.extra_options,
+            self.cargo_artifact
+                .as_ref()
+                .expect("bindgen ran before cargo build"),
         )?;
         info!("wasm bindings were built at {:#?}.", &self.out_dir);
         Ok(())