[browser][wasm] Fix buffered symbol asset loading by elringus · Pull Request #127087 · dotnet/runtime

elringus · 2026-04-17T17:42:35Z

This fixes SymbolsAsset.buffer handling in the browser runtime and adds a WBT regression test for buffered runtime assets:

Fixed the browser loader so symbols assets supplied via buffer are handled correctly, instead of effectively requiring pendingDownload
Kept the symbols path working with the existing text-based symbol map loading flow
Added BufferedAssetsTest to WasmBasicTestApp that supplies these runtime assets via buffer:
- dotnetwasm
- assemblies
- pdbs
- symbols
Added a matching ModuleConfigTests.BufferedAssetsTest integration test

The issue was discussed with @pavelsavara on .NET's Discord server.

Note: I was not able to run the browser test end-to-end in the local environment due local WBT/workload packaging setup issues. If anything fails on CI, I’ll follow up and fix the remaining issues there.

Copilot

Pull request overview

Fixes buffered symbols runtime asset loading in the browser WASM loader, and adds a regression scenario in WBT to exercise supplying runtime assets via asset.buffer.

Changes:

Adjusted asset instantiation flow to correctly handle symbols assets when provided via buffer (and enabled buffered-response .text() decoding).
Added a BufferedAssetsTest scenario to WasmBasicTestApp that assigns buffer for wasm/assemblies/pdbs/symbols during onConfigLoaded.
Added a matching ModuleConfigTests.BufferedAssetsTest publish-and-run integration test.

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 1 comment.

File	Description
src/mono/wasm/testassets/WasmBasicTestApp/App/wwwroot/main.js	Adds the `BufferedAssetsTest` scenario that supplies runtime assets via `asset.buffer`.
src/mono/wasm/Wasm.Build.Tests/ModuleConfigTests.cs	Adds an integration test that publishes and runs the new scenario (with symbol map emission enabled).
src/mono/browser/runtime/loader/assets.ts	Fixes loader handling for buffered `symbols` assets and implements `.text()` for buffered-response shim.

elringus · 2026-04-17T22:50:19Z

It seems the fingerprint stuff doesn't support file names with hashes. Is it somehow possible to generate the symbols file without the hash? Or maybe I should also patch the fingerprint resolver to ignore the hash on symbols?

Found unknown files in C:\helix\work\workitem\e\wbt artifacts\ModuleConfigTests_BufferedAssetsTest_Debug_False_0zxtutco_2je_鿀蜒枛遫䡫煉\App\bin\Debug\net11.0\publish\wwwroot_framework:
dotnet.native.8o3vuf3rfy.js.symbols
Add these to GetAllKnownDotnetFilesToFingerprintMap method

dotnet-policy-service · 2026-04-18T14:55:37Z

Tagging subscribers to 'arch-wasm': @lewing, @pavelsavara
See info in area-owners.md if you want to be subscribed.

pavelsavara · 2026-04-20T06:11:25Z

Log

Wasm.Build.Tests.ModuleConfigTests.BufferedAssetsTest [FAIL]
      Found unknown files in /root/helix/work/workitem/e/wbt artifacts/ModuleConfigTests_BufferedAssetsTest_Debug_False_zwqmgjzy_he5_鿀蜒枛遫䡫煉/App/bin/Debug/net11.0/publish/wwwroot/_framework:
          dotnet.native.gkigrwomkb.js.symbols
      Add these to GetAllKnownDotnetFilesToFingerprintMap method
      Expected dotnet.js
        dotnet.native.js
        dotnet.native.wasm
        dotnet.runtime.js
      Options AssertBundleOptions { Configuration = Debug, BuildOptions = PublishOptions { IsPublish = True, TargetFramework = net11.0, AOT = False, ExpectedFileType = FromRuntimePack, GlobalizationMode = Sharded, CustomIcuFile = , UseCache = True, ExpectSuccess = True, AssertAppBundle = True, Label = , WarnAsError = True, RuntimeType = SingleThreaded, ExtraBuildEnvironmentVariables = System.Collections.Generic.Dictionary`2[System.String,System.String], NonDefaultFrameworkDir = , ExtraMSBuildArgs = -p:CompressionEnabled=false -p:WasmEnableHotReload=false, EnableDiagnostics = False, BuildOnlyAfterPublish = True, ExpectRelinkDirWhenPublishing = False }, ExpectedFileType = FromRuntimePack, BinFrameworkDir = /root/helix/work/workitem/e/wbt artifacts/ModuleConfigTests_BufferedAssetsTest_Debug_False_zwqmgjzy_he5_鿀蜒枛遫䡫煉/App/bin/Debug/net11.0/publish/wwwroot/_framework, ExpectSymbolsFile = True, AssertIcuAssets = True, AssertSymbolsFile = False, ExpectDotnetJsFingerprinting =  } 
      
      Stack Trace:
        /_/src/mono/wasm/Wasm.Build.Tests/ProjectProviderBase.cs(165,0): at Wasm.Build.Tests.ProjectProviderBase.FindAndAssertDotnetFiles(String binFrameworkDir, AssertBundleOptions assertOptions, IReadOnlyDictionary`2 superSet, IReadOnlySet`1 expected)
        /_/src/mono/wasm/Wasm.Build.Tests/ProjectProviderBase.cs(83,0): at Wasm.Build.Tests.ProjectProviderBase.FindAndAssertDotnetFiles(AssertBundleOptions assertOptions)
        /_/src/mono/wasm/Wasm.Build.Tests/ProjectProviderBase.cs(49,0): at Wasm.Build.Tests.ProjectProviderBase.AssertBasicBundle(AssertBundleOptions assertOptions)
        /_/src/mono/wasm/Wasm.Build.Tests/WasmSdkBasedProjectProvider.cs(111,0): at Wasm.Build.Tests.WasmSdkBasedProjectProvider.AssertBundle(AssertBundleOptions assertOptions)
        /_/src/mono/wasm/Wasm.Build.Tests/WasmSdkBasedProjectProvider.cs(97,0): at Wasm.Build.Tests.WasmSdkBasedProjectProvider.AssertBundle(Configuration config, MSBuildOptions buildOptions, Boolean isUsingWorkloads, Nullable`1 isNativeBuild, Nullable`1 wasmFingerprintDotnetJs)
        /_/src/mono/wasm/Wasm.Build.Tests/WasmSdkBasedProjectProvider.cs(181,0): at Wasm.Build.Tests.WasmSdkBasedProjectProvider.AssertWasmSdkBundle(Configuration config, MSBuildOptions buildOptions, Boolean isUsingWorkloads, Nullable`1 isNativeBuild, Nullable`1 wasmFingerprintDotnetJs, String buildOutput)
        /_/src/mono/wasm/Wasm.Build.Tests/Templates/WasmTemplateTestsBase.cs(265,0): at Wasm.Build.Tests.WasmTemplateTestsBase.BuildProjectCore(ProjectInfo info, Configuration configuration, MSBuildOptions buildOptions, Nullable`1 isNativeBuild, Nullable`1 wasmFingerprintDotnetJs)
        /_/src/mono/wasm/Wasm.Build.Tests/Templates/WasmTemplateTestsBase.cs(181,0): at Wasm.Build.Tests.WasmTemplateTestsBase.PublishProject(ProjectInfo info, Configuration configuration, Nullable`1 isNativeBuild, Nullable`1 wasmFingerprintDotnetJs)
        /_/src/mono/wasm/Wasm.Build.Tests/ModuleConfigTests.cs(108,0): at Wasm.Build.Tests.ModuleConfigTests.BufferedAssetsTest()
        --- End of stack trace from previous location ---

Log

 Wasm.Build.Tests.ModuleConfigTests.BufferedAssetsTest [FAIL]
      System.Exception : Expected exit code 0 but got 1.
      consoleOutput=Failed to load resource: the server responded with a status of 404 (Not Found)
      Failed to load resource: the server responded with a status of 404 (Not Found)
      MONO_WASM: onConfigLoaded() failed TypeError: config.resources.corePdb is not iterable
      MONO_WASM: Failed to initialize config TypeError: config.resources.corePdb is not iterable TypeError: config.resources.corePdb is not iterable
          at Object.onConfigLoaded (http://127.0.0.1:41655/main.js:603:21)
          at xe (http://127.0.0.1:41655/main.js:136:20568)
          at async http://127.0.0.1:41655/main.js:136:29683
          at async http://127.0.0.1:41655/main.js:136:34856
          at async Object.create (http://127.0.0.1:41655/main.js:136:34826)
          at async http://127.0.0.1:41655/main.js:616:70
      Error: Failed to initialize config TypeError: config.resources.corePdb is not iterable TypeError: config.resources.corePdb is not iterable
          at Object.onConfigLoaded (http://127.0.0.1:41655/main.js:603:21)
          at xe (http://127.0.0.1:41655/main.js:136:20568)
          at async http://127.0.0.1:41655/main.js:136:29683
          at async http://127.0.0.1:41655/main.js:136:34856
          at async Object.create (http://127.0.0.1:41655/main.js:136:34826)
          at async http://127.0.0.1:41655/main.js:616:70
          at xe (http://127.0.0.1:41655/main.js:136:20880)
          at async http://127.0.0.1:41655/main.js:136:29683
          at async http://127.0.0.1:41655/main.js:136:34856
          at async Object.create (http://127.0.0.1:41655/main.js:136:34826)
          at async http://127.0.0.1:41655/main.js:616:70
      WASM EXIT 1

pavelsavara · 2026-04-21T10:23:45Z

Log

dotnet.runtime.y92zvik3q0.js }
    Wasm.Build.Tests.ModuleConfigTests.BufferedAssetsTest [FAIL]
      Found unknown files in /root/helix/work/workitem/e/wbt artifacts/ModuleConfigTests_BufferedAssetsTest_Debug_False_j4harjjp_1r1_鿀蜒枛遫䡫煉/App/bin/Debug/net11.0/publish/wwwroot/_framework:
          dotnet.native.gkigrwomkb.js.symbols
      Add these to GetAllKnownDotnetFilesToFingerprintMap method
      Expected dotnet.js
        dotnet.native.js
        dotnet.native.wasm
        dotnet.runtime.js

elringus · 2026-04-21T11:09:58Z

dotnet.native.gkigrwomkb.js.symbols

The thing is, dotnet.native.js.symbols already exists under GetAllKnownDotnetFilesToFingerprintMap. But it doesn't seem to support hashes.

runtime/src/mono/wasm/Wasm.Build.Tests/WasmSdkBasedProjectProvider.cs

Lines 28 to 48 in 6f2ad2d

    
           protected override IReadOnlyDictionary<string, bool> GetAllKnownDotnetFilesToFingerprintMap(AssertBundleOptions assertOptions) 
        
           { 
        
               var result = new SortedDictionary<string, bool>() 
        
               { 
        
                   { "dotnet.js", true }, 
        
                   { "dotnet.js.map", false }, 
        
                   { "dotnet.native.js", true }, 
        
                   { "dotnet.native.js.symbols", true }, 
        
                   { "dotnet.native.wasm", true }, 
        
                   { "dotnet.native.worker.mjs", true }, 
        
                   { "dotnet.runtime.js", true }, 
        
                   { "dotnet.runtime.js.map", false }, 
        
                   { "dotnet.diagnostics.js", true }, 
        
                   { "dotnet.diagnostics.js.map", false }, 
        
               }; 
        
               if (assertOptions.ExpectDotnetJsFingerprinting == false) 
        
                   result["dotnet.js"] = false; 
        
               return result; 
        
           }

maraf · 2026-04-22T09:48:07Z

I think the logic that asserts the files incorrectly finds where the fingerprint should be, see https://github.com/elringus/dotnet/blob/fix/symbols-buffer/src/mono/wasm/Wasm.Build.Tests/ProjectProviderBase.cs#L116 (dotnet.native.{FP}.js.symbols vs dotnet.native.js.{FP}.symbols)

elringus · 2026-04-26T19:01:57Z

Would it be ok to add a special case for .js.symbols in FindAndAssertDotnetFiles?

pavelsavara · 2026-05-25T08:31:44Z

Would it be ok to add a special case for .js.symbols in FindAndAssertDotnetFiles?

@maraf is that what you mean ?

Copilot

Pull request overview

Copilot reviewed 3 out of 3 changed files in this pull request and generated 1 comment.

Copilot

Pull request overview

Copilot reviewed 4 out of 4 changed files in this pull request and generated 3 comments.

Copilot

Pull request overview

Copilot reviewed 4 out of 4 changed files in this pull request and generated 3 comments.

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Pull request overview

Copilot reviewed 4 out of 4 changed files in this pull request and generated 2 comments.

elringus · 2026-06-09T12:03:08Z

@maraf All green now. Let me know if any tweaks are required.

maraf

Looks good to me 👍
Thank you for the contribution!

Copilot

Pull request overview

Copilot reviewed 4 out of 4 changed files in this pull request and generated 3 comments.

Copilot

Pull request overview

Copilot reviewed 4 out of 4 changed files in this pull request and generated 4 comments.

elringus · 2026-06-11T14:20:09Z

CI triage: the failures are unrelated to this PR — same legs are red on main (Blazor boot failures → #129182, CoreCLR IcuTests relink → #128219, windows legs canceled by a Helix queue timeout without running). The new BufferedAssetsTest passed on both Mono and CoreCLR.

pavelsavara · 2026-06-11T15:06:01Z

LGTM, thanks! @elringus

pavelsavara · 2026-06-11T15:06:14Z

/ba-g unrelated failures

fix symbols buffer

f3053fd

elringus requested review from ilonatommy, lewing and maraf as code owners April 17, 2026 17:42

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github-actions Bot added the area-Build-mono label Apr 17, 2026

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Comment thread src/mono/wasm/testassets/WasmBasicTestApp/App/wwwroot/main.js

This was referenced Apr 17, 2026

[browser] Wasm.Build.Tests timeout - Timed out after 10s waiting for 'WASM EXIT' #116697

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Assertion failed: new_time >= loop->time in Component Governance Detection dotnet/dnceng#6510

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pavelsavara self-assigned this Apr 18, 2026

pavelsavara added arch-wasm WebAssembly architecture os-browser Browser variant of arch-wasm labels Apr 18, 2026

pavelsavara assigned maraf Apr 18, 2026

remove missing assets

b0dadf3

build-analysis Bot mentioned this pull request Apr 20, 2026

Unable to pull image from mcr.microsoft.com #117164

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Merge branch 'main' into fix/symbols-buffer

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Comment thread src/mono/browser/runtime/loader/assets.ts

Comment thread src/mono/browser/runtime/loader/assets.ts

elringus added 2 commits June 8, 2026 21:10

disable bundle assert

d021dd5

try resolve asset url

034bd93

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Comment thread src/mono/wasm/testassets/WasmBasicTestApp/App/wwwroot/main.js

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Comment thread src/mono/wasm/Wasm.Build.Tests/ProjectProviderBase.cs

elringus added 2 commits June 9, 2026 12:48

copy symbols in bundler mode

2a72075

opt-out of bundler friendly category

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Comment thread src/mono/wasm/testassets/WasmBasicTestApp/App/wwwroot/main.js

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Merge branch 'main' into fix/symbols-buffer

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Comment thread src/mono/wasm/Wasm.Build.Tests/ModuleConfigTests.cs Outdated

run on coreclr

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Comment thread src/mono/browser/runtime/loader/assets.ts

Comment thread src/mono/wasm/testassets/WasmBasicTestApp/App/wwwroot/main.js

Comment thread src/mono/browser/runtime/loader/assets.ts

Merge branch 'main' into fix/symbols-buffer

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Merge branch 'main' into fix/symbols-buffer

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Comment thread src/mono/wasm/testassets/WasmBasicTestApp/App/wwwroot/main.js

Comment thread src/mono/wasm/testassets/WasmBasicTestApp/App/wwwroot/main.js

Merge branch 'main' into fix/symbols-buffer

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build-analysis Bot mentioned this pull request Jun 11, 2026

MSBuild crashing in the build #92290

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pavelsavara merged commit 30db3f7 into dotnet:main Jun 11, 2026
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dotnet-maestro Bot mentioned this pull request Jun 11, 2026

[main] Source code updates from dotnet/runtime dotnet/dotnet#7196

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