Fix WebGPU ConvTranspose bias validation in TypeScript and C++ implementations

js/web/lib/wasm/jsep/webgpu/ops/conv-transpose.ts

@@ -132,7 +132,7 @@ export const parseConvTransposeAttributes = (attributes: Record<string, unknown>
     typeof attributes.autoPad == 'undefined' ? 0 : (attributes.autoPad as number)
   ];
   const dilations = attributes.dilations as [number, number];
-  const group = attributes.group as number;
+  const group = (attributes.group as number) ?? 1; // default to 1 per ONNX spec
   const kernelShape = attributes.kernelShape as [number, number];
   const pads = attributes.pads as [number, number, number, number];
   const strides = attributes.strides as [number, number];
@@ -178,11 +178,17 @@ const validateInputs = (inputs: readonly TensorView[], attributes: ConvTranspose
     throw new Error('FILTER_IN_CHANNEL should be equal to DATA_CHANNEL');
   }
 
-  const featureMaps = inputs[1].dims[1] * attributes.group;
-
   // if bias is provided it should be 1D and the number of elements should be equal to the number of feature maps
-  if (inputs.length === 3 && (inputs[2].dims.length !== 1 || inputs[2].dims[0] !== featureMaps)) {
-    throw new Error('invalid bias');
+  if (inputs.length === 3) {
+    if (inputs[2].dims.length !== 1) {
+      throw new Error('invalid bias: bias must be 1D tensor');
+    }
+    const featureMaps = inputs[1].dims[1] * attributes.group;
+    if (inputs[2].dims[0] !== featureMaps) {
+      throw new Error(
+        `invalid bias: bias size (${inputs[2].dims[0]}) must be equal to output channels (${featureMaps})`,
+      );
+    }
   }
 
   const spatialRank = inputs[0].dims.length - 2;

onnxruntime/core/providers/webgpu/nn/conv_transpose.cc

@@ -57,6 +57,17 @@ Status ConvTranspose<is_channels_last>::ComputeInternal(ComputeContext& context)
 
   bool has_bias = context.InputCount() > 2;
   const auto* bias = has_bias ? context.Input<Tensor>(2) : nullptr;
+  // Validate bias shape if provided
+  if (has_bias) {
+    const auto& bias_shape = bias->Shape();
+    if (bias_shape.NumDimensions() != 1) {
+      return ORT_MAKE_STATUS(ONNXRUNTIME, INVALID_ARGUMENT, "invalid bias: bias must be 1D tensor");
+    }
+    if (bias_shape[0] != num_output_channels) {
+      return ORT_MAKE_STATUS(ONNXRUNTIME, INVALID_ARGUMENT, "invalid bias: bias size (", bias_shape[0],
+                             ") must be equal to output channels (", num_output_channels, ")");
+    }
+  }
   if (input_shape.NumDimensions() == 3 && filter_shape.NumDimensions() == 3) {
     // ConvTranspose1D
     TensorShapeVector input_shape_vector = input_shape.AsShapeVector();