Bug 316293 – WebGPU: RenderPipeline/ComputePipeline creation failure lacks detailed validation error

• Status: RESOLVED
• Resolution: FIXED
• Component: WebGPU

Created attachment 479977 [details]
Error Log

Hello,

When launching my WASM/WebGPU application, errors occur during the creation of RenderPipeline and ComputePipeline objects, but Safari does not display any detailed diagnostic or validation message.

URL:
https://grenzwert.net/wasm-modules/MedicalViewer/MedicalViewer

In Google Chrome, the application starts successfully without any pipeline state object creation errors. Also, when an issue is caused by user-side WebGPU code, Chrome usually provides detailed information in the console log, which makes the problem much easier to diagnose.

Environment:
- Device: MacBook Pro
- GPU: Apple M3 Max
- OS: macOS 26.5
- Browser: Safari 26.6
- Works in Chrome: Yes
- Firefox: Not a valid comparison in this case, because the application requires texture-formats-tier1, which is currently not supported there

Expected result:
The application should either create the render and compute pipelines successfully, or Safari should provide a detailed WebGPU validation/diagnostic message explaining why pipeline creation failed.

Actual result:
Pipeline creation fails in Safari, but no detailed error message is shown.

Could you please investigate this issue, or improve the diagnostic output for WebGPU pipeline creation failures in Safari?

[Radar WebKit Bug Importer]

<rdar://problem/179334632>

[Mike Wyrzykowski]

It looks like a shader is failing to compile. We do generate a validation error at GPUShaderModule creation time, but it looks like this isn't passed through to the render or compute pipeline creation.

328:30: no matching overload for initializer textureSampleLevel(ref<handle, texture_1d<f32>, read>, ref<handle, sampler, read>, f32, f32)

[Mike Wyrzykowski]

Created attachment 480108 [details]
Attaching shader source

[Mike Wyrzykowski]

Failing line is:

                  let v_164 = textureSampleLevel(g_TF_Opacity, g_TextureLUT_sampler, v_163, 0.0f).x;

[Mike Wyrzykowski]

@group(1u) @binding(5u) var g_TF_Opacity : texture_1d<f32>;
@group(0u) @binding(2u) var g_TextureLUT_sampler : sampler;
v_163 is a float

The `textureSampleLevel` signature seems valid according to the specification.
https://www.w3.org/TR/WGSL/#texturesamplelevel

[Mike Wyrzykowski]

Created attachment 480109 [details]
works-after-that-change

[Mike Wyrzykowski]

Pull request: https://github.com/WebKit/WebKit/pull/67197

Thanks you

[Mike Wyrzykowski]

Filed https://bugs.webkit.org/show_bug.cgi?id=317143 to improve the error message during pipeline creation

[EWS]

Committed 315278@main (5b1956e908ba): <https://commits.webkit.org/315278@main>

Reviewed commits have been landed. Closing PR #67197 and removing active labels.