chore: remove broken Emscripten host

.github/workflows/platforms.yml

@@ -405,34 +405,6 @@ jobs:
         working-directory: examples/ios-feedback
         run: xcodebuild -scheme cpal-ios-example -configuration Debug -derivedDataPath build -sdk iphonesimulator -arch arm64
 
-  # WebAssembly - Emscripten
-  wasm-emscripten:
-    runs-on: ubuntu-latest
-    env:
-      TARGET: wasm32-unknown-emscripten
-    steps:
-      - uses: actions/checkout@v5
-
-      - name: Setup Emscripten toolchain
-        uses: mymindstorm/setup-emsdk@v14
-
-      - name: Install Rust MSRV (${{ env.MSRV_WASM }})
-        uses: dtolnay/rust-toolchain@master
-        with:
-          toolchain: ${{ env.MSRV_WASM }}
-          targets: ${{ env.TARGET }}
-
-      - name: Rust Cache
-        uses: Swatinem/rust-cache@v2
-        with:
-          key: wasm-emscripten
-
-      - name: Check examples (default features)
-        run: cargo +${{ env.MSRV_WASM }} check --examples --workspace --verbose --target ${{ env.TARGET }}
-
-      - name: Check examples (no default features)
-        run: cargo +${{ env.MSRV_WASM }} check --examples --no-default-features --workspace --verbose --target ${{ env.TARGET }}
-
   # WebAssembly - wasm-bindgen
   wasm-bindgen:
     runs-on: ubuntu-latest
@@ -574,7 +546,6 @@ jobs:
       - macos
       - android
       - ios
-      - wasm-emscripten
       - wasm-bindgen
       - wasm-audioworklet
       - wasm-wasip1

.github/workflows/quality.yml

@@ -65,12 +65,6 @@ jobs:
             features: ""
             os: ubuntu-latest
 
-          # WASM - Emscripten
-          - target: wasm32-unknown-emscripten
-            name: WASM-emscripten
-            features: ""
-            os: ubuntu-latest
-
           # WASM - wasm-bindgen feature
           - target: wasm32-unknown-unknown
             name: WASM-bindgen

CHANGELOG.md

@@ -72,6 +72,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 ### Removed
 
 - Replaced `StreamInstant::add()` and `sub()` by `checked_add()`/`+` and `checked_sub()`/`-`.
+- **Emscripten**: Removed broken host; use the WebAudio host instead.
 
 ### Fixed
 
@@ -94,7 +95,6 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - **ASIO**: Poisoned stream mutex in the buffer-size change handler no longer silently skips the
   update.
 - **CoreAudio**: Fix undefined behaviour and silent failure in loopback device creation.
-- **Emscripten**: Fix build failure introduced by newer `wasm-bindgen` versions.
 - **JACK**: Fix input capture timestamp using callback execution time instead of cycle start.
 - **JACK**: Poisoned error callback mutex no longer silently drops subsequent error notifications.
 - **JACK**: Port registration failure now fails stream creation instead of silently failing.

Cargo.toml

@@ -161,21 +161,6 @@ objc2-avf-audio = { version = "0.3", default-features = false, features = [
     "AVAudioSessionTypes",
 ] }
 
-[target.'cfg(target_os = "emscripten")'.dependencies]
-wasm-bindgen = { version = "0.2" }
-wasm-bindgen-futures = "0.4"
-js-sys = { version = "0.3" }
-web-sys = { version = "0.3", features = [
-    "AudioContext",
-    "AudioContextOptions",
-    "AudioBuffer",
-    "AudioBufferSourceNode",
-    "AudioNode",
-    "AudioDestinationNode",
-    "Window",
-    "AudioContextState",
-] }
-
 [target.'cfg(all(target_arch = "wasm32", target_os = "unknown"))'.dependencies]
 wasm-bindgen = { version = "0.2", optional = true }
 wasm-bindgen-futures = { version = "0.4", optional = true }
@@ -227,7 +212,6 @@ targets = [
     "aarch64-apple-darwin",
     "aarch64-apple-ios",
     "wasm32-unknown-unknown",
-    "wasm32-unknown-emscripten",
     "aarch64-linux-android",
     "x86_64-unknown-freebsd",
     "x86_64-unknown-netbsd",

README.md

@@ -35,7 +35,6 @@ Currently, supported platforms include:
 
 - Android (via AAudio)
 - BSD (via ALSA by default, JACK, PipeWire or PulseAudio optionally)
-- Emscripten
 - iOS (via CoreAudio)
 - Linux (via ALSA by default, JACK, PipeWire or PulseAudio optionally)
 - macOS (via CoreAudio by default, JACK optionally)

UPGRADING.md

@@ -14,6 +14,7 @@ This guide covers breaking changes requiring code updates. See [CHANGELOG.md](CH
 - [ ] Update `StreamInstant::new(secs, nanos)` call sites: `secs` is now `u64`.
 - [ ] Update `StreamInstant::from_nanos(nanos)` call sites: `nanos` is now `u64`.
 - [ ] Update `duration_since` call sites to pass by value (drop the `&`).
+- [ ] Migrate `wasm32-unknown-emscripten` to `wasm32-unknown-unknown` if possible.
 
 ## 1. Error enums are now `#[non_exhaustive]`
 
@@ -134,6 +135,30 @@ StreamInstant::new(0_u64, 0);
 
 **Why:** All audio host clocks are positive and monotonic; they are never negative.
 
+## 5. `wasm32-unknown-emscripten` target removed
+
+**What changed:** The `emscripten` audio host and the `wasm32-unknown-emscripten` build target are no longer supported.
+
+Migrate to `wasm32-unknown-unknown` and enable the `wasm-bindgen` feature:
+
+```toml
+# Before (v0.17)
+cpal = { version = "0.17", features = ["emscripten"] }
+
+# After (v0.18)
+cpal = { version = "0.18", features = ["wasm-bindgen"] }
+```
+
+Then select the `webaudio` host at runtime:
+
+```rust
+let host = cpal::host_from_id(cpal::HostId::WebAudio)?;
+```
+
+If you must target `wasm32-unknown-emscripten` specifically, consider using OpenAL or another audio approach that supports that target, as cpal no longer provides audio on Emscripten.
+
+**Why:** The old `emscripten` host relied on deprecated Emscripten audio APIs that are no longer functional.
+
 ---
 
 # Upgrading from v0.16 to v0.17