[browser] Remove custom cache

[maraf]

The only remaining use-case for custom cache is when using standalone mode & having misconfigured HTTP server. In that case the behaviour of the custom cache can be recreated in user code.

Fixes #85775

[Copilot]

Pull Request Overview

This PR removes the custom caching support from the browser runtime, as it is no longer needed for the remaining use-case. Key changes include conditional removal of cache settings in the boot JSON generation, elimination of caching helper functions from the TypeScript interfaces and globals, and complete removal of the assetsCache implementation.

Reviewed Changes

Copilot reviewed 9 out of 10 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
src/tasks/Microsoft.NET.Sdk.WebAssembly.Pack.Tasks/GenerateWasmBootJson.cs	Added a conditional branch to only set cacheBootResources for legacy targets
src/mono/browser/runtime/types/internal.ts	Removed LoaderHelpers functions related to custom cache logging and purging
src/mono/browser/runtime/types/index.ts	Removed the cacheBootResources property from the MonoConfig type
src/mono/browser/runtime/startup.ts	Removed calls to cache-related functions previously used during startup
src/mono/browser/runtime/loader/run.ts	Removed cache initialization calls from the runtime loader
src/mono/browser/runtime/loader/globals.ts	Removed cache helper imports from the loader globals
src/mono/browser/runtime/loader/assetsCache.ts	Completely removed the custom cache implementation file
src/mono/browser/runtime/loader/assets.ts	Updated resource download logic to eliminate usage of cache-based fetching

Files not reviewed (1)

• src/mono/nuget/Microsoft.NET.Sdk.WebAssembly.Pack/build/Microsoft.NET.Sdk.WebAssembly.Browser.targets: Language not supported

Comments suppressed due to low confidence (8)

src/mono/browser/runtime/types/internal.ts:166

• The removal of 'logDownloadStatsToConsole' from LoaderHelpers may impact parts of the runtime expecting this functionality. Please verify that all consumers of LoaderHelpers have been updated accordingly.

-    logDownloadStatsToConsole: () => void;

src/mono/browser/runtime/types/internal.ts:167

• Removing 'purgeUnusedCacheEntriesAsync' could affect resource cache maintenance; ensure that any dependent code now operates correctly without it.

-    purgeUnusedCacheEntriesAsync: () => Promise<void>;

src/mono/browser/runtime/types/index.ts:120

• The removal of 'cacheBootResources' from MonoConfig should be reviewed to ensure that all configuration-dependent code has been updated accordingly.

-    cacheBootResources?: boolean,

src/mono/browser/runtime/startup.ts:338

• The deletion of the block invoking cache-related logging and purge functions must be validated so that startup behavior remains correct without custom cache support.

-        if (loaderHelpers.config.debugLevel !== 0 && loaderHelpers.config.cacheBootResources) {

src/mono/browser/runtime/loader/run.ts:511

• Removing the cache initialization call aligns with the removal of custom caching; please confirm that this does not adversely affect asset loading in any expected scenarios.

-    await initCacheToUseIfEnabled();

src/mono/browser/runtime/loader/globals.ts:122

• Ensure that the removal of cache helper functions from the globals does not leave any stale references in the codebase.

-        logDownloadStatsToConsole,

src/mono/browser/runtime/loader/assetsCache.ts:1

• Since the entire assetsCache.ts file has been removed, please verify that all modules previously importing this file have been updated to no longer reference any custom cache logic.

-// Licensed to the .NET Foundation under one or more agreements.

src/mono/browser/runtime/loader/assets.ts:676

• Replacing the call to 'download_resource_with_cache' with 'fetchResource' appropriately removes custom caching; ensure that this change is thoroughly tested in all asset loading scenarios.

-        const fetchResponse = download_resource_with_cache(asset);

[javiercn]

Looks good.

How are we planning to detect that webassembly is available in auto mode? (it essentially check for wasm availability and starts server if not or starts wasm directly if available)