🎯 Execution provider clarity

EP structs like ep::CUDA are now compile-time gated behind their respective Cargo feature flags. The EP feature flags only modifying runtime behavior was a common pain point, and this change brings ort in line with, like, every other Rust crate in existence.

⚠️ ort will now throw an error at link time if download-binaries is enabled and no binaries contain all of the requested EPs. Previously, if you enabled a nonsensical combination like cuda + coreml, ort would silently fall back to a CPU-only build. This caused great confusion as the only indicator of what went wrong was in log messages that don't show by default. A new lax-feature-matching Cargo feature will fallback to the closest fit instead of erroring.

🍎 ONNX Runtime 1.28

rc.13 skips ahead 4 ONNX Runtime versions to v1.28, bringing new operator support, bug & security fixes, and performance improvements.

✖️ No CUDA 12

rc.13 only ships CUDA 13 binaries, as ONNX Runtime has deprecated CUDA 12.

🧩 Custom operator ergonomics

Custom operators have been reworked to have a more Rusty interface:

 struct MyOperator;
 
 impl Operator for MyOperator {
+	type Kernel<'attr> = ort::operator::BoxedKernel<'attr>;
 
 	fn name(&self) -> &str {
 		"MyOperator"
 	}
 
-	fn inputs(&self) -> Vec<OperatorInput> {
-		vec![OperatorInput::required(TensorElementType::Float32), OperatorInput::required(TensorElementType::Float32)]
+	fn inputs(&self) -> impl IntoIterator<Item = OperatorInput> {
+		[OperatorInput::required(TensorElementType::Float32), OperatorInput::required(TensorElementType::Float32)]
 	}
 
-	fn outputs(&self) -> Vec<OperatorOutput> {
-		vec![OperatorOutput::required(TensorElementType::Float32)]
+	fn outputs(&self) -> impl IntoIterator<Item = OperatorOutput> {
+		[OperatorOutput::required(TensorElementType::Float32)]
 	}
 
-	fn create_kernel(&self, _: &KernelAttributes) -> ort::Result<Box<dyn Kernel>> {
-		Ok(Box::new(|ctx: &KernelContext| {
+	fn create_kernel<'attr>(&self, _: &KernelContext<'attr>) -> ort::Result<Self::Kernel<'attr>> {
+		Ok(Box::new(|ctx: &ComputeContext| {
 			...
 		}))
 	}
 }

ℹ️ Custom diagnostic messages

ort now uses the wonderful #[diagnostic] attributes to drastically improve the clarity of commonly encountered errors.

☑️ Miri-approved

Test coverage was expanded and ort was ran against Miri, and a few unsoundness bugs were fixed.

✨ Other features

• 8db51e7 Add VSINPU EP
• 5688cce (ort-web): Allow creating tensors from images.
• 726dc7c Expose the DirectML EP API.
• 5e669f6 Support string array operator attributes
• 5f99738 Support float16 tensor usage with the native f16 type on nightly Rust
• 62ad710 (ort-candle): Update candle to 0.11
• d5dc28f (ort-tract): Update tract to 0.23

🔧 Other fixes

• d5eb59f Committing a session which has a map input/output will no longer panic.
• d2838f8 Fixed the fallback behavior when ort-sys can't create a system-wide cache dir.
• 26f656b Allow DynTensor to be Cloned.
• e336d6b Allow 0 dimensions in tensors.
• 14e9d29 Fix tensor byte size calculation for 8-bit floating point types.
• 7bdabcc Allow try_extract_scalar to work on tensors with shape [1].
• 85f6074 Fixed retrieving string attributes in custom operator shape inference contexts.
• 17ed727 Don't deadlock when load-dynamic fails.
• a5ee3ad Don't force std for ndarray when std is enabled.
• d535605 Allow copy-dylibs to work independently of download-binaries.
• 49413ba Rerun build.rs on macOS when Xcode updates.
• bb20575 Warn when AVX-2 isn't supported when using pyke binaries.
• 9c840a3 Support FreeBSD.
• 01f377b Support Mac Catalyst.