Fix multithreaded browser-wasm build: CS0102 errors in PortableThreadPool; remove redundant ThreadPoolBoundHandle.Browser.Threads.cs; regenerate WASM call helpers by Copilot · Pull Request #125887 · dotnet/runtime

Copilot · 2026-03-21T13:48:47Z

Fix build breaks introduced by #125507 (comment)

Co-authored-by: jkotas <[email protected]> Agent-Logs-Url: https://github.com/dotnet/runtime/sessions/d91ee3bf-535d-41ed-9587-cbb58c135dcd

...es/System.Private.CoreLib/src/System/Threading/ThreadPoolBoundHandle.PlatformNotSupported.cs

…Browser.Threads variant Co-authored-by: jkotas <[email protected]> Agent-Logs-Url: https://github.com/dotnet/runtime/sessions/db60b8c8-f071-4c80-9401-71646c2bde1e

dotnet-policy-service · 2026-03-21T14:02:33Z

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jkotas · 2026-03-21T14:09:25Z

@copilot Fix build breaks

src/libraries/System.Private.CoreLib/src/System.Private.CoreLib.Shared.projitems(2870,95): error MSB4092: (NETCORE_ENGINEERING_TELEMETRY=Restore) An unexpected token "==" was found at character position 60 in condition "'$(TargetsWindows)' != 'true' and not ('$(TargetsBrowser)' == 'true' and '$(FeatureMultithreading)' == 'true')".

…valent Co-authored-by: jkotas <[email protected]> Agent-Logs-Url: https://github.com/dotnet/runtime/sessions/7a223942-d407-49d2-b0fc-b96d86ade2c3

Copilot · 2026-03-21T14:12:47Z

@copilot Fix build breaks

src/libraries/System.Private.CoreLib/src/System.Private.CoreLib.Shared.projitems(2870,95): error MSB4092: (NETCORE_ENGINEERING_TELEMETRY=Restore) An u...

Fixed in 9e1283b. MSBuild doesn't support not (...), replaced with the De Morgan equivalent: ('$(TargetsBrowser)' != 'true' or '$(FeatureMultithreading)' != 'true').

jkotas · 2026-03-21T14:20:49Z

/azp run runtime-extra-platforms

azure-pipelines · 2026-03-21T14:21:01Z

Azure Pipelines successfully started running 1 pipeline(s).

src/libraries/System.Private.CoreLib/src/System.Private.CoreLib.Shared.projitems

Copilot

Pull request overview

This PR fixes multithreaded Browser WASM (TargetsBrowser=true + FeatureMultithreading=true) build breaks in CoreLib caused by duplicate type/member definitions from overlapping platform-specific source inclusions.

Changes:

Remove ThreadPoolBoundHandle.Browser.Threads.cs and its projitems entry to avoid conflicting ThreadPoolBoundHandle definitions with the non-Windows ThreadPoolBoundHandle.PlatformNotSupported.cs.
Update the PortableThreadPool.Unix.cs compile condition to exclude it for multithreaded Browser WASM builds, avoiding duplicate CpuUtilizationReader / WorkerThread.IsIOPending members with PortableThreadPool.Browser.Threads.cs.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

File	Description
`src/libraries/System.Private.CoreLib/src/System/Threading/ThreadPoolBoundHandle.Browser.Threads.cs`	Deletes a redundant Browser+threads-specific partial that conflicts with the non-Windows PlatformNotSupported implementation.
`src/libraries/System.Private.CoreLib/src/System.Private.CoreLib.Shared.projitems`	Adjusts MSBuild compile conditions to prevent Unix and Browser.Threads variants from being included together in multithreaded Browser WASM builds.

jkotas · 2026-03-21T14:23:57Z

/azp run runtime-extra-platforms

azure-pipelines · 2026-03-21T14:24:09Z

Azure Pipelines successfully started running 1 pipeline(s).

jkotas · 2026-03-21T14:38:18Z

@copilot Regenerate wasm call helpers under https://github.com/dotnet/runtime/tree/main/src/coreclr/vm/wasm

Co-authored-by: jkotas <[email protected]> Agent-Logs-Url: https://github.com/dotnet/runtime/sessions/47266637-e546-4255-99d4-608dcd1f7cc2

Copilot · 2026-03-21T15:02:58Z

@copilot Regenerate wasm call helpers under https://github.com/dotnet/runtime/tree/main/src/coreclr/vm/wasm

Done in 312fed0. Built the browser-wasm runtime locally and regenerated the call helpers. Changes: new P/Invoke entries (SystemNative_FcntlGetIsNonBlocking, SystemNative_Pipe, SystemNative_ReadFromNonblocking, SystemNative_WriteToNonblocking), new reverse P/Invoke entries for TypeMapLazyDictionary.NewPrecachedExternalTypeMap/NewPrecachedProxyTypeMap, and updated interp-to-managed thunk signatures.

jkotas · 2026-03-22T07:10:39Z

/ba-g infrastructure timeout

Fix multithreaded browser-wasm build errors (CS0260, CS0102)

5941b65

Co-authored-by: jkotas <[email protected]> Agent-Logs-Url: https://github.com/dotnet/runtime/sessions/d91ee3bf-535d-41ed-9587-cbb58c135dcd

Copilot AI assigned Copilot and jkotas Mar 21, 2026

Copilot created this pull request from a session on behalf of jkotas March 21, 2026 13:48 View session

jkotas reviewed Mar 21, 2026

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...es/System.Private.CoreLib/src/System/Threading/ThreadPoolBoundHandle.PlatformNotSupported.cs Outdated Show resolved Hide resolved

Copilot started work on behalf of jkotas March 21, 2026 13:49 View session

Revert partial on ThreadPoolBoundHandle.PlatformNotSupported; delete …

ee1a863

…Browser.Threads variant Co-authored-by: jkotas <[email protected]> Agent-Logs-Url: https://github.com/dotnet/runtime/sessions/db60b8c8-f071-4c80-9401-71646c2bde1e

Copilot AI changed the title ~~Fix multithreaded browser-wasm build: CS0260 and CS0102 errors in ThreadPoolBoundHandle/PortableThreadPool~~ Fix multithreaded browser-wasm build: CS0102 errors in PortableThreadPool; remove redundant ThreadPoolBoundHandle.Browser.Threads.cs Mar 21, 2026

Copilot AI requested a review from jkotas March 21, 2026 13:53

Copilot stopped work on behalf of jkotas due to an error March 21, 2026 13:53
The "Restore solution" custom setup step from your .github/workflows/copilot-setup-steps.yml file failed.

github-actions bot added the area-System.Threading label Mar 21, 2026

Copilot started work on behalf of jkotas March 21, 2026 14:09 View session

Fix MSBuild condition syntax: replace 'not (...)' with De Morgan equi…

9e1283b

…valent Co-authored-by: jkotas <[email protected]> Agent-Logs-Url: https://github.com/dotnet/runtime/sessions/7a223942-d407-49d2-b0fc-b96d86ade2c3

Copilot stopped work on behalf of jkotas due to an error March 21, 2026 14:13
The "Restore solution" custom setup step from your .github/workflows/copilot-setup-steps.yml file failed.

jkotas marked this pull request as ready for review March 21, 2026 14:20

Copilot AI review requested due to automatic review settings March 21, 2026 14:20

Copilot started reviewing on behalf of jkotas March 21, 2026 14:21 View session

jkotas reviewed Mar 21, 2026

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src/libraries/System.Private.CoreLib/src/System.Private.CoreLib.Shared.projitems Outdated Show resolved Hide resolved

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Copilot AI reviewed Mar 21, 2026

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jkotas mentioned this pull request Mar 21, 2026

Consolidate overlapped I/O non-Windows stubs; remove stale ILLink workaround; remove incorrect [RequiresUnsafe] annotations #125507

Merged

Copilot started work on behalf of jkotas March 21, 2026 14:38 View session

Regenerate WASM CoreCLR call helpers

312fed0

Co-authored-by: jkotas <[email protected]> Agent-Logs-Url: https://github.com/dotnet/runtime/sessions/47266637-e546-4255-99d4-608dcd1f7cc2

Copilot AI requested a review from jkotas March 21, 2026 15:04

Copilot finished work on behalf of jkotas March 21, 2026 15:04

jkotas requested a review from AaronRobinsonMSFT March 21, 2026 16:29

jkotas mentioned this pull request Mar 21, 2026

Fix pal_memory.c on OpenBSD #125010

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pavelsavara approved these changes Mar 21, 2026

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build-analysis bot mentioned this pull request Mar 21, 2026

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

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jkotas merged commit 6260db3 into main Mar 22, 2026
158 of 160 checks passed

jkotas deleted the copilot/fix-multithreaded-browser-wasm-build branch March 22, 2026 07:11

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Fix multithreaded browser-wasm build: CS0102 errors in PortableThreadPool; remove redundant ThreadPoolBoundHandle.Browser.Threads.cs; regenerate WASM call helpers#125887

Fix multithreaded browser-wasm build: CS0102 errors in PortableThreadPool; remove redundant ThreadPoolBoundHandle.Browser.Threads.cs; regenerate WASM call helpers#125887
jkotas merged 5 commits intomainfrom
copilot/fix-multithreaded-browser-wasm-build

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edited by jkotas

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Copilot AI commented Mar 21, 2026 •

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