fix: remove default() and new() where not cross-platform compatible

CHANGELOG.md

@@ -36,22 +36,14 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - **AAudio**: Streams now request `PERFORMANCE_MODE_LOW_LATENCY` when the `realtime` feature is
   enabled; stream error callback receives `ErrorKind::RealtimeDenied` if not granted.
 - **AAudio**: `Device` now implements `PartialEq`, `Eq`, `Hash`, and `Debug`.
-- **AAudio**: `Host` and `Device` now implement `Default`; added `Device::new()`.
 - **ALSA**: `device_by_id()` now accepts PCM shorthand names such as `hw:0,0` and `plughw:foo`.
 - **ASIO**: `Device` now implements `Debug`.
-- **AudioWorklet**: `Device` and `Host` now implement `Default`; added `Device::new()`.
-- **CoreAudio**: `Host` now implements `Default`.
 - **CoreAudio**: tvOS target support (Tier 3, requires nightly).
 - **CoreAudio**: `Device` now implements `PartialEq`, `Eq`, and `Hash`.
-- **CoreAudio (iOS)**: `Device` now implements `Default`; added `Device::new()`.
 - **JACK**: `Device` now implements `PartialEq`, `Eq`, and `Hash`.
-- **Null**: `Device`, `Host`, `Stream`, `SupportedInputConfigs`, and `SupportedOutputConfigs` now
-  implement `Default`, added `new()` on each.
 - **PipeWire**: New host for Linux and some BSDs using the PipeWire API.
 - **PulseAudio**: New host for Linux and some BSDs using the PulseAudio API.
 - **WASAPI**: `Device` now implements `PartialEq`, `Eq`, `Hash`, and `Debug`.
-- **WASAPI**: `Host` now implements `Default`.
-- **WebAudio**: `Device` and `Host` now implement `Default`; added `Device::new()`.
 
 ### Changed
 
@@ -152,6 +144,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 - Replaced `StreamInstant::add()` and `sub()` by `checked_add()`/`+` and `checked_sub()`/`-`.
 - Removed deprecated `DeviceTrait::name()`.
+- **ALSA**: `Default` implementation for `Device`.
 - **ALSA**: `AlsaHost` is no longer re-exported from `cpal::platform`.
 - **Emscripten**: Removed broken host; use the WebAudio host instead.
 - **WASAPI**: Removed `U24` incorrectly listed as a supported sample format.
@@ -189,7 +182,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - **ASIO**: Fix `driver.sample_rate()` failures at stream creation being silently ignored.
 - **ASIO**: Fix callbacks firing before `build_*_stream` returns the `Stream` handle.
 - **ASIO**: Fix overrun not being reported when the driver reports `kAsioOverload`.
-- **AudioWorklet**: Fix `Devices::default()` to enumerate only if `Host::is_available()`.
+- **AudioWorklet**: Fix `default_output_device()` to return `None` when AudioWorklet is unavailable.
 - **CoreAudio**: Fix default output streams silently stopping when the system default output
   device is unplugged; they now reroute automatically or report `ErrorKind::DeviceNotAvailable`.
 - **CoreAudio**: Fix undefined behaviour and silent failure in loopback device creation.
@@ -216,6 +209,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
   devices.
 - **WebAudio**: Fix duplicated callbacks on repeated `play()` calls.
 - **WebAudio**: Report errors through the callback instead of panicking.
+- **WebAudio**: Fix `default_output_device()` to return `None` when WebAudio is unavailable.
+
 
 ## [0.17.3] - 2026-02-18
 

src/host/aaudio/mod.rs

@@ -121,18 +121,11 @@ const SAMPLE_RATES: [i32; 15] = [
 /// The same default for blocking operations as Oboe uses
 const DEFAULT_TIMEOUT_NANOS: i64 = 2_000_000_000;
 
-#[derive(Default)]
 pub struct Host;
 
-#[derive(Clone, Debug, Default)]
+#[derive(Clone, Debug)]
 pub struct Device(Option<AudioDeviceInfo>);
 
-impl Device {
-    pub fn new() -> Self {
-        Self::default()
-    }
-}
-
 /// Stream wraps AudioStream in Arc<Mutex<>> to provide Send + Sync semantics.
 ///
 /// While the underlying ndk::audio::AudioStream is neither Send nor Sync in ndk 0.9.0
@@ -199,16 +192,16 @@ impl HostTrait for Host {
                 .collect::<Vec<_>>()
                 .into_iter())
         } else {
-            Ok(vec![Device::new()].into_iter())
+            Ok(vec![Device(None)].into_iter())
         }
     }
 
     fn default_input_device(&self) -> Option<Self::Device> {
-        Some(Device::default())
+        Some(Device(None))
     }
 
     fn default_output_device(&self) -> Option<Self::Device> {
-        Some(Device::default())
+        Some(Device(None))
     }
 }
 

src/host/alsa/mod.rs

@@ -115,6 +115,17 @@ impl Host {
             inner: Arc::new(inner),
         })
     }
+
+    // "default" is a virtual ALSA device that redirects to the configured default. We cannot
+    // determine its actual capabilities without opening it, so we return Unknown direction.
+    fn default_device(&self) -> Device {
+        Device {
+            pcm_id: DEFAULT_DEVICE.to_owned(),
+            desc: Some("Default Audio Device".to_owned()),
+            direction: DeviceDirection::Unknown,
+            _context: self.inner.clone(),
+        }
+    }
 }
 
 impl HostTrait for Host {
@@ -138,11 +149,11 @@ impl HostTrait for Host {
     }
 
     fn default_input_device(&self) -> Option<Self::Device> {
-        Some(Self::Device::default())
+        Some(self.default_device())
     }
 
     fn default_output_device(&self) -> Option<Self::Device> {
-        Some(Self::Device::default())
+        Some(self.default_device())
     }
 }
 
@@ -651,21 +662,6 @@ impl std::hash::Hash for Device {
     }
 }
 
-impl Default for Device {
-    fn default() -> Self {
-        // "default" is a virtual ALSA device that redirects to the configured default. We cannot
-        // determine its actual capabilities without opening it, so we return Unknown direction.
-        Self {
-            pcm_id: DEFAULT_DEVICE.to_owned(),
-            desc: Some("Default Audio Device".to_owned()),
-            direction: DeviceDirection::Unknown,
-            _context: Arc::new(
-                AlsaContext::new().expect("Failed to initialize ALSA configuration"),
-            ),
-        }
-    }
-}
-
 /// Strategy for pre-filling an output buffer with the equilibrium value.
 #[derive(Debug)]
 enum EquilibriumFill {

src/host/audioworklet/mod.rs

@@ -30,23 +30,16 @@ use crate::dependent_module;
 /// Content is false if the iterator is empty.
 pub struct Devices(bool);
 
-#[derive(Clone, Debug, Default, PartialEq, Eq, Hash)]
+#[derive(Clone, Debug, PartialEq, Eq, Hash)]
 pub struct Device;
 
-impl Device {
-    pub fn new() -> Self {
-        Self
-    }
-}
-
 impl fmt::Display for Device {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         let desc = self.description().map_err(|_| fmt::Error)?;
         f.write_str(desc.name())
     }
 }
 
-#[derive(Default)]
 pub struct Host;
 
 pub struct Stream {
@@ -120,7 +113,7 @@ impl HostTrait for Host {
 
 impl Devices {
     fn new() -> Result<Self, Error> {
-        Ok(Self::default())
+        Ok(Devices(Host::is_available()))
     }
 }
 
@@ -417,12 +410,6 @@ impl Drop for Stream {
     }
 }
 
-impl Default for Devices {
-    fn default() -> Self {
-        Self(Host::is_available())
-    }
-}
-
 impl Iterator for Devices {
     type Item = Device;
 

src/host/coreaudio/ios/enumerate.rs

@@ -4,19 +4,7 @@ use super::Device;
 pub use crate::iter::{SupportedInputConfigs, SupportedOutputConfigs};
 
 // TODO: Support enumerating earpiece vs headset vs speaker etc?
-pub struct Devices(VecIntoIter<Device>);
-
-impl Devices {
-    pub fn new() -> Self {
-        Self::default()
-    }
-}
-
-impl Default for Devices {
-    fn default() -> Self {
-        Self(vec![Device].into_iter())
-    }
-}
+pub struct Devices(pub(super) VecIntoIter<Device>);
 
 impl Iterator for Devices {
     type Item = Device;

src/host/coreaudio/ios/mod.rs

@@ -36,7 +36,7 @@ use session_event_manager::SessionEventManager;
 // These days the default of iOS is now F32 and no longer I16
 const SUPPORTED_SAMPLE_FORMAT: SampleFormat = SampleFormat::F32;
 
-#[derive(Clone, Debug, Default, PartialEq, Eq, Hash)]
+#[derive(Clone, Debug, PartialEq, Eq, Hash)]
 pub struct Device;
 
 impl fmt::Display for Device {
@@ -46,7 +46,6 @@ impl fmt::Display for Device {
     }
 }
 
-#[derive(Default)]
 pub struct Host;
 
 impl Host {
@@ -64,7 +63,7 @@ impl HostTrait for Host {
     }
 
     fn devices(&self) -> Result<Self::Devices, Error> {
-        Ok(Devices::new())
+        Ok(Devices(vec![Device].into_iter()))
     }
 
     fn default_input_device(&self) -> Option<Self::Device> {
@@ -77,10 +76,6 @@ impl HostTrait for Host {
 }
 
 impl Device {
-    pub fn new() -> Self {
-        Self
-    }
-
     fn description(&self) -> Result<DeviceDescription, Error> {
         // Query AVAudioSession to determine actual input/output availability
         // SAFETY: AVAudioSession::sharedInstance() returns the global audio session singleton

src/host/coreaudio/macos/mod.rs

@@ -25,7 +25,7 @@ mod property_listener;
 pub use device::Device;
 
 /// Coreaudio host, the default host on macOS.
-#[derive(Debug, Default)]
+#[derive(Debug)]
 pub struct Host;
 
 impl Host {

src/host/null/mod.rs

@@ -12,10 +12,9 @@ use crate::{
     SupportedStreamConfig, SupportedStreamConfigRange,
 };
 
-#[derive(Default)]
 pub struct Devices;
 
-#[derive(Clone, Debug, Default, PartialEq, Eq, Hash)]
+#[derive(Clone, Debug, PartialEq, Eq, Hash)]
 pub struct Device;
 
 impl fmt::Display for Device {
@@ -25,58 +24,27 @@ impl fmt::Display for Device {
     }
 }
 
-#[derive(Default)]
 pub struct Host;
 
-#[derive(Debug, Clone, Default, PartialEq, Eq, Hash)]
+#[derive(Debug, Clone, PartialEq, Eq, Hash)]
 pub struct Stream;
 
 // Compile-time assertion that Stream is Send and Sync
 crate::assert_stream_send!(Stream);
 crate::assert_stream_sync!(Stream);
 
-#[derive(Clone, Default)]
+#[derive(Clone)]
 pub struct SupportedInputConfigs;
-#[derive(Clone, Default)]
+#[derive(Clone)]
 pub struct SupportedOutputConfigs;
 
-impl Device {
-    pub fn new() -> Self {
-        Self
-    }
-}
-
 impl Host {
     #[allow(dead_code)]
     pub fn new() -> Result<Self, Error> {
         Ok(Self)
     }
 }
 
-impl Stream {
-    pub fn new() -> Self {
-        Self
-    }
-}
-
-impl SupportedInputConfigs {
-    pub fn new() -> Self {
-        Self
-    }
-}
-
-impl SupportedOutputConfigs {
-    pub fn new() -> Self {
-        Self
-    }
-}
-
-impl Devices {
-    pub fn new() -> Result<Self, Error> {
-        Ok(Self)
-    }
-}
-
 impl DeviceTrait for Device {
     type SupportedInputConfigs = SupportedInputConfigs;
     type SupportedOutputConfigs = SupportedOutputConfigs;
@@ -147,7 +115,7 @@ impl HostTrait for Host {
     }
 
     fn devices(&self) -> Result<Self::Devices, Error> {
-        Devices::new()
+        Ok(Devices)
     }
 
     fn default_input_device(&self) -> Option<Self::Device> {

src/host/wasapi/mod.rs

@@ -23,7 +23,7 @@ mod stream;
 /// Note: If you use a WASAPI output device as an input device it will
 /// transparently enable loopback mode (see
 /// https://docs.microsoft.com/en-us/windows/win32/coreaudio/loopback-recording).
-#[derive(Debug, Default)]
+#[derive(Debug)]
 pub struct Host;
 
 impl Host {

src/host/webaudio/mod.rs

@@ -37,7 +37,7 @@ type ClosureHandle = Arc<RwLock<Option<Closure<dyn FnMut()>>>>;
 /// Content is false if the iterator is empty.
 pub struct Devices(bool);
 
-#[derive(Clone, Debug, Default, PartialEq, Eq, Hash)]
+#[derive(Clone, Debug, PartialEq, Eq, Hash)]
 pub struct Device;
 
 impl fmt::Display for Device {
@@ -47,7 +47,6 @@ impl fmt::Display for Device {
     }
 }
 
-#[derive(Default)]
 pub struct Host;
 
 pub struct Stream {
@@ -108,15 +107,11 @@ impl HostTrait for Host {
 
 impl Devices {
     fn new() -> Result<Self, Error> {
-        Ok(Self::default())
+        Ok(Devices(is_webaudio_available()))
     }
 }
 
 impl Device {
-    pub fn new() -> Self {
-        Self
-    }
-
     fn description(&self) -> Result<DeviceDescription, Error> {
         Ok(DeviceDescriptionBuilder::new("Default Device")
             .direction(DeviceDirection::Output)
@@ -626,13 +621,6 @@ impl Drop for Stream {
     }
 }
 
-impl Default for Devices {
-    fn default() -> Devices {
-        // We produce an empty iterator if the WebAudio API isn't available.
-        Devices(is_webaudio_available())
-    }
-}
-
 impl Iterator for Devices {
     type Item = Device;