Fix DeviceModifier

The issue is the key is selected before the modification happens
which means the devices in the pool will not match the key.

I can't think of a way to fix this using the adaptor so maybe
this hacky solution works by letting you modify the key.

Generally you just append a string but I made it function because
MaxLimitsTestMixin wants to be able to chain to other modifiers.

Maybe it should all be re-designed

This came up because I notice a test passing that shouldn't have
passed. It passsed because a `MaxLimitsTestMixin` test ran first
and it's key was `''` which meant that other tests got a max limits
device from the pool.

src/webgpu/api/operation/device/all_limits_and_features.spec.ts

@@ -8,7 +8,7 @@ import {
   GPUTestSubcaseBatchState,
   initUncanonicalizedDeviceDescriptor,
 } from '../../../gpu_test.js';
-import { CanonicalDeviceDescriptor, DescriptorModifierFn } from '../../../util/device_pool.js';
+import { CanonicalDeviceDescriptor, DescriptorModifier } from '../../../util/device_pool.js';
 
 /**
  * Gets the adapter limits as a standard JavaScript object.
@@ -36,18 +36,25 @@ function setAllLimitsToAdapterLimitsAndAddAllFeatures(
 }
 
 /**
- * Used by MaxLimitsTest to request a device with all the max limits of the adapter.
+ * Used to request a device with all the max limits of the adapter.
  */
 export class AllLimitsAndFeaturesGPUTestSubcaseBatchState extends GPUTestSubcaseBatchState {
   override selectDeviceOrSkipTestCase(
     descriptor: DeviceSelectionDescriptor,
-    descriptorModifierFn?: DescriptorModifierFn
+    descriptorModifier?: DescriptorModifier
   ): void {
-    const wrapper = (adapter: GPUAdapter, desc: CanonicalDeviceDescriptor | undefined) => {
-      desc = descriptorModifierFn ? descriptorModifierFn(adapter, desc) : desc;
-      return setAllLimitsToAdapterLimitsAndAddAllFeatures(adapter, desc);
+    const mod: DescriptorModifier = {
+      descriptorModifier(adapter: GPUAdapter, desc: CanonicalDeviceDescriptor | undefined) {
+        desc = descriptorModifier?.descriptorModifier
+          ? descriptorModifier.descriptorModifier(adapter, desc)
+          : desc;
+        return setAllLimitsToAdapterLimitsAndAddAllFeatures(adapter, desc);
+      },
+      keyModifier(baseKey: string) {
+        return `${baseKey}:AllLimitsAndFeaturesTest`;
+      },
     };
-    super.selectDeviceOrSkipTestCase(initUncanonicalizedDeviceDescriptor(descriptor), wrapper);
+    super.selectDeviceOrSkipTestCase(initUncanonicalizedDeviceDescriptor(descriptor), mod);
   }
 }
 

src/webgpu/gpu_test.ts

@@ -43,7 +43,7 @@ import { CommandBufferMaker, EncoderType } from './util/command_buffer_maker.js'
 import { ScalarType } from './util/conversion.js';
 import {
   CanonicalDeviceDescriptor,
-  DescriptorModifierFn,
+  DescriptorModifier,
   DevicePool,
   DeviceProvider,
   UncanonicalizedDeviceDescriptor,
@@ -156,13 +156,13 @@ export class GPUTestSubcaseBatchState extends SubcaseBatchState {
    */
   selectDeviceOrSkipTestCase(
     descriptor: DeviceSelectionDescriptor,
-    descriptorModifierFn?: DescriptorModifierFn
+    descriptorModifier?: DescriptorModifier
   ): void {
     assert(this.provider === undefined, "Can't selectDeviceOrSkipTestCase() multiple times");
     this.provider = devicePool.acquire(
       this.recorder,
       initUncanonicalizedDeviceDescriptor(descriptor),
-      descriptorModifierFn
+      descriptorModifier
     );
     // Suppress uncaught promise rejection (we'll catch it later).
     this.provider.catch(() => {});
@@ -1334,13 +1334,20 @@ function setAllLimitsToAdapterLimits(
 export class MaxLimitsGPUTestSubcaseBatchState extends GPUTestSubcaseBatchState {
   override selectDeviceOrSkipTestCase(
     descriptor: DeviceSelectionDescriptor,
-    descriptorModifierFn?: DescriptorModifierFn
+    descriptorModifier?: DescriptorModifier
   ): void {
-    const wrapper = (adapter: GPUAdapter, desc: CanonicalDeviceDescriptor | undefined) => {
-      desc = descriptorModifierFn ? descriptorModifierFn(adapter, desc) : desc;
-      return setAllLimitsToAdapterLimits(adapter, desc);
+    const mod: DescriptorModifier = {
+      descriptorModifier(adapter: GPUAdapter, desc: CanonicalDeviceDescriptor | undefined) {
+        desc = descriptorModifier?.descriptorModifier
+          ? descriptorModifier.descriptorModifier(adapter, desc)
+          : desc;
+        return setAllLimitsToAdapterLimits(adapter, desc);
+      },
+      keyModifier(baseKey: string) {
+        return `${baseKey}:MaxLimits`;
+      },
     };
-    super.selectDeviceOrSkipTestCase(initUncanonicalizedDeviceDescriptor(descriptor), wrapper);
+    super.selectDeviceOrSkipTestCase(initUncanonicalizedDeviceDescriptor(descriptor), mod);
   }
 }
 
@@ -1466,7 +1473,7 @@ export interface TextureTestMixinType {
    * Effectively it's a Uint8Array to Uint8Array copy that
    * does the same thing as `writeTexture` but because the
    * destination is a buffer you have to provide the parameters
-   * of the destination buffer similarly to how you'd provide them
+   * of the destination buffer similarly to how you'esc provide them
    * to `copyTextureToBuffer`
    */
   updateLinearTextureDataSubBox(

src/webgpu/util/device_pool.ts

@@ -23,10 +23,35 @@ class TestFailedButDeviceReusable extends Error {}
 class FeaturesNotSupported extends Error {}
 export class TestOOMedShouldAttemptGC extends Error {}
 
-export type DescriptorModifierFn = (
-  adapter: GPUAdapter,
-  desc: CanonicalDeviceDescriptor | undefined
-) => CanonicalDeviceDescriptor;
+/**
+ * DescriptorModifier lets you supply a function to select a device
+ * based on the limits/features available from the adapter.
+ * Devices pooled based on a key and that key is derived before
+ * an adapter is requested. That means you select key without
+ * knowledge of what the adapter will provide. You do this by
+ * providing a keyModifier function that appends a suffix.
+ *
+ * For example: If your modifier adds all the limits you might
+ * choose 'maxLimits' are your suffix
+ *
+ * ```js
+ *   keyModifier(s: string) { return `${s}:maxLimits`; },
+ * ```
+ *
+ * If your modifier selects only `maxBindGroups` and `maxColorAttachments`
+ * then your suffix might be `maxBindGroups&maxColorAttachments`
+ *
+ * ```js
+ *   keyModifier(s: string) { return `${s}:maxBindGroups&maxColorAttachments`; },
+ * ```
+ */
+export type DescriptorModifier = {
+  keyModifier(baseKey: string): string;
+  descriptorModifier(
+    adapter: GPUAdapter,
+    desc: CanonicalDeviceDescriptor | undefined
+  ): CanonicalDeviceDescriptor;
+};
 
 export class DevicePool {
   private holders: 'uninitialized' | 'failed' | DescriptorToHolderMap = 'uninitialized';
@@ -35,13 +60,13 @@ export class DevicePool {
   async acquire(
     recorder: TestCaseRecorder,
     descriptor: UncanonicalizedDeviceDescriptor | undefined,
-    descriptorModifierFn: DescriptorModifierFn | undefined
+    descriptorModifier: DescriptorModifier | undefined
   ): Promise<DeviceProvider> {
     let errorMessage = '';
     if (this.holders === 'uninitialized') {
       this.holders = new DescriptorToHolderMap();
       try {
-        await this.holders.getOrCreate(recorder, undefined, descriptorModifierFn);
+        await this.holders.getOrCreate(recorder, undefined, descriptorModifier);
       } catch (ex) {
         this.holders = 'failed';
         if (ex instanceof Error) {
@@ -55,7 +80,7 @@ export class DevicePool {
       `WebGPU device failed to initialize${errorMessage}; not retrying`
     );
 
-    const holder = await this.holders.getOrCreate(recorder, descriptor, descriptorModifierFn);
+    const holder = await this.holders.getOrCreate(recorder, descriptor, descriptorModifier);
 
     assert(holder.state === 'free', 'Device was in use on DevicePool.acquire');
     holder.state = 'acquired';
@@ -150,9 +175,10 @@ class DescriptorToHolderMap {
   async getOrCreate(
     recorder: TestCaseRecorder,
     uncanonicalizedDescriptor: UncanonicalizedDeviceDescriptor | undefined,
-    descriptorModifierFn: DescriptorModifierFn | undefined
+    descriptorModifier: DescriptorModifier | undefined
   ): Promise<DeviceHolder> {
-    const [descriptor, key] = canonicalizeDescriptor(uncanonicalizedDescriptor);
+    const [descriptor, baseKey] = canonicalizeDescriptor(uncanonicalizedDescriptor);
+    const key = descriptorModifier?.keyModifier(baseKey) || baseKey;
     // Quick-reject descriptors that are known to be unsupported already.
     if (this.unsupported.has(key)) {
       throw new SkipTestCase(
@@ -174,7 +200,7 @@ class DescriptorToHolderMap {
     // No existing item was found; add a new one.
     let value;
     try {
-      value = await DeviceHolder.create(recorder, descriptor, descriptorModifierFn);
+      value = await DeviceHolder.create(recorder, descriptor, descriptorModifier);
     } catch (ex) {
       if (ex instanceof FeaturesNotSupported) {
         this.unsupported.add(key);
@@ -313,13 +339,13 @@ class DeviceHolder implements DeviceProvider {
   static async create(
     recorder: TestCaseRecorder,
     descriptor: CanonicalDeviceDescriptor | undefined,
-    descriptorModifierFn: DescriptorModifierFn | undefined
+    descriptorModifier: DescriptorModifier | undefined
   ): Promise<DeviceHolder> {
     const gpu = getGPU(recorder);
     const adapter = await gpu.requestAdapter();
     assert(adapter !== null, 'requestAdapter returned null');
-    if (descriptorModifierFn) {
-      descriptor = descriptorModifierFn(adapter, descriptor);
+    if (descriptorModifier) {
+      descriptor = descriptorModifier.descriptorModifier(adapter, descriptor);
     }
     if (!supportsFeature(adapter, descriptor)) {
       throw new FeaturesNotSupported('One or more features are not supported');