[browser][mono][MT] Prep for emscripten upgrade#129503
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/azp run runtime-wasm |
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Pull request overview
This PR updates the Mono browser (WASM threads) runtime and sample to align with expected Emscripten threading/runtime changes: switching pthread id retrieval to pthread_self, passing a compiled WebAssembly.Module into workers, and ensuring PThread is exported at link time.
Changes:
- Update pthread identity and worker startup plumbing (use
pthread_self, propagatewasmModule/wasmMemory/handler metadata to workers, adjust whenpreRunWorkerruns). - Adjust default pthread pool sizing and the browser-threads sample configuration/build properties.
- Export Emscripten
PThreadas an exported runtime method when threads are enabled.
Reviewed changes
Copilot reviewed 12 out of 12 changed files in this pull request and generated 4 comments.
Show a summary per file
| File | Description |
|---|---|
| src/mono/sample/wasm/browser-threads/wwwroot/main.js | Sets a larger pthreadPoolInitialSize in the sample config. |
| src/mono/sample/wasm/browser-threads/Wasm.Browser.Threads.Sample.csproj | Tweaks WASM build properties for debugging/asset behavior during the upgrade prep. |
| src/mono/browser/runtime/types/internal.ts | Updates Emscripten module typing (wasmModule now a WebAssembly.Module + adds wasmMemory/handlers). |
| src/mono/browser/runtime/startup.ts | Switches to pthread_self, adjusts worker instantiation flow, and calls preRunWorker after instantiation. |
| src/mono/browser/runtime/pthreads/worker-thread.ts | Removes mono_wasm_pthread_ptr usage and adjusts worker lifecycle hooks. |
| src/mono/browser/runtime/pthreads/ui-thread.ts | Changes worker message handling and loads wasm module before wiring message handling. |
| src/mono/browser/runtime/pthreads/shared.ts | Removes mono_wasm_pthread_ptr helper. |
| src/mono/browser/runtime/pthreads/index.ts | Stops re-exporting mono_wasm_pthread_ptr. |
| src/mono/browser/runtime/loader/worker.ts | Worker-side config receive path updated to accept richer payload (module/memory/handlers). |
| src/mono/browser/runtime/loader/config.ts | Changes default pthreadPoolInitialSize (5 → 7). |
| src/mono/browser/runtime/cwraps.ts | Adds pthread_self cwrap signature. |
| src/mono/browser/build/BrowserWasmApp.targets | Exports PThread via EXPORTED_RUNTIME_METHODS when threads enabled. |
Co-authored-by: Copilot Autofix powered by AI <175728472+Copilot@users.noreply.github.com>
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…adingSupported - disable WebWorkerTest
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Pull request overview
Copilot reviewed 24 out of 24 changed files in this pull request and generated 1 comment.
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src/libraries/System.Runtime.InteropServices.JavaScript/tests/System.Runtime.InteropServices.JavaScript.UnitTests/System.Runtime.InteropServices.JavaScript.Tests.csproj:68
- This change comments out the entire ItemGroup that includes the WebWorker-specific test sources for
WasmEnableThreads == true. Leaving test sources disabled via an XML comment makes it easy to forget to re-enable them, and removes coverage for MT scenarios.
If these tests are temporarily broken, prefer an explicit MSBuild condition (or an ActiveIssue/ConditionalFact-based skip inside the tests) so the intent is discoverable and can be reverted cleanly. Otherwise, please re-enable the ItemGroup.
<!--
<ItemGroup Condition="'$(WasmEnableThreads)' == 'true'">
<Compile Include="$(MSBuildThisFileDirectory)System\Runtime\InteropServices\JavaScript\WebWorkerTestBase.cs" />
<Compile Include="$(MSBuildThisFileDirectory)System\Runtime\InteropServices\JavaScript\WebWorkerTest.cs" />
<Compile Include="$(MSBuildThisFileDirectory)System\Runtime\InteropServices\JavaScript\WebWorkerTest.Http.cs" />
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/azp run runtime-wasm |
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Azure Pipelines successfully started running 1 pipeline(s). |
maraf
approved these changes
Jun 18, 2026
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/azp run runtime-wasm |
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Azure Pipelines successfully started running 1 pipeline(s). |
lewing
approved these changes
Jun 18, 2026
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/ba-g known failures |
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This is in prep for emscripten bump which changes MT significantly. JS interop is broken in MT.
Common.TestsRuntimeFeature.IsMultithreadingSupportedworker.queueand early subscription to responsesmono_wasm_pthread_ptrwithpthread_self