[browser][wasm] Prep changes ahead of emsdk bump by pavelsavara · Pull Request #129383 · dotnet/runtime

pavelsavara · 2026-06-14T13:34:07Z

Split off from #129299

Summary

This PR carries the WASM changes that are independent of the upcoming Emscripten 5.0.6 / LLVM 23 toolchain bump, so they can be reviewed and merged on their own. Splitting them out keeps the toolchain-bump PR focused on the parts that actually require the new SDK.

What's included

1. Browser version bump — Firefox / GeckoDriver

eng/testing/BrowserVersions.props — Firefox 125.0.1 → 140.11.0esr, GeckoDriver 0.34.0 → 0.37.0
eng/testing/wasm-provisioning.targets — Firefox archive .tar.bz2 → .tar.xz (new Mozilla release format)

Fully independent of the toolchain; just updates the browsers used for WASM testing.

2. Keepalive / timer balance fixes (runtime bug fixes)

src/mono/browser/runtime/scheduling.ts — balance clearTimeout with runtimeKeepalivePop, and reset lastScheduledTimeoutId before executing the timer tick
src/mono/browser/runtime/diagnostics/dotnet-gcdump.ts — runtimeKeepalivePop when a pending GC-dump timeout is cleared
src/mono/browser/runtime/startup.ts — remove a stray, unbalanced runtimeKeepalivePop on the error path
src/mono/browser/runtime/loader/exit.ts — only run flush_node_streams under Node

These correct the runtime keepalive ref-count so the event loop can drain/exit properly; unrelated to the SDK version.

3. Disable `WASM_BIGINT` for corerun / Node (DWARF debugger workaround)

src/coreclr/hosts/corerun/CMakeLists.txt — link corerun with -sWASM_BIGINT=0 under Node without HEAP64/HEAPU64 views are not exported when BigInt is off
docs/workflow/building/coreclr/wasm.md — update the Node debug-launch args

(cherry picked from commit fa8db40)

(cherry picked from commit 4113f8e)

(cherry picked from commit 5ad201d)

(cherry picked from commit 0dab167)

(cherry picked from commit 3bcf4d0)

(cherry picked from commit 53a6d16)

(cherry picked from commit 7f3a839)

Copilot

Pull request overview

This PR updates .NET’s WASM/Browser infrastructure and runtime glue code, focusing on browser test provisioning updates and WASM runtime behavior adjustments (timers/keepalive and WASM_BIGINT-related export/link behavior).

Changes:

Update WASM test browser provisioning by bumping Firefox/GeckoDriver versions and switching Linux Firefox downloads to .tar.xz.
Fix/adjust runtime keepalive accounting around timers/GC dump timeouts and startup error paths.
Modify CoreCLR WASM build/export behavior around WASM_BIGINT (notably exported HEAP views) and corerun Node linking options; update WASM build/debug docs accordingly.

Reviewed changes

Copilot reviewed 10 out of 10 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
src/mono/browser/runtime/startup.ts	Adjusts keepalive behavior on runtime initialization failure path.
src/mono/browser/runtime/scheduling.ts	Balances keepalive with timer rescheduling and adjusts timer tick bookkeeping order.
src/mono/browser/runtime/loader/exit.ts	Guards Node-only stream flushing to avoid running it outside Node.
src/mono/browser/runtime/diagnostics/dotnet-gcdump.ts	Balances keepalive when rescheduling/canceling GC dump stop timeout.
src/coreclr/runtime.proj	Introduces a target affecting WASM_BIGINT-related export selection for browser builds.
src/coreclr/hosts/corerun/CMakeLists.txt	Changes corerun Node link flags to explicitly disable `WASM_BIGINT`.
eng/testing/wasm-provisioning.targets	Switches Linux Firefox provisioning URL from `.tar.bz2` to `.tar.xz`.
eng/testing/BrowserVersions.props	Bumps Firefox/GeckoDriver versions used in WASM test runs.
eng/native.wasm.targets	Expands exported Emscripten runtime methods (HEAP views) and gates HEAP64/HEAPU64 on a property.
docs/workflow/building/coreclr/wasm.md	Updates Node debugging launch args.

Copilot

Pull request overview

Copilot reviewed 9 out of 10 changed files in this pull request and generated 4 comments.

Copilot

Pull request overview

Copilot reviewed 9 out of 9 changed files in this pull request and generated 2 comments.

Co-authored-by: Copilot Autofix powered by AI <175728472+Copilot@users.noreply.github.com>

Copilot

Pull request overview

Copilot reviewed 9 out of 9 changed files in this pull request and generated 2 comments.

Copilot

Pull request overview

Copilot reviewed 44 out of 44 changed files in this pull request and generated 2 comments.

Copilot

Pull request overview

Copilot reviewed 9 out of 9 changed files in this pull request and generated 3 comments.

pavelsavara · 2026-06-14T20:16:26Z

/ba-g known CI issues

pavelsavara added 7 commits June 14, 2026 15:24

export memory from Module

d9a5256

(cherry picked from commit fa8db40)

don't node flush streams in a browser

a7a8e0d

(cherry picked from commit 4113f8e)

WASM_BIGINT=0 for node testing

0aea51d

(cherry picked from commit 5ad201d)

balance runtimeKeepalivePop

3a24a58

(cherry picked from commit 0dab167)

balance clearTimeout

c9fa612

(cherry picked from commit 3bcf4d0)

disable WASM_BIGINT for corerun - NodeJS

2f3d9c2

(cherry picked from commit 53a6d16)

Bump FireFox to 140.11.0esr

549e9fd

(cherry picked from commit 7f3a839)

pavelsavara added this to the 11.0.0 milestone Jun 14, 2026

pavelsavara requested a review from akoeplinger June 14, 2026 13:34

pavelsavara self-assigned this Jun 14, 2026

pavelsavara requested a review from lewing as a code owner June 14, 2026 13:34

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pavelsavara added arch-wasm WebAssembly architecture area-Build-mono os-browser Browser variant of arch-wasm labels Jun 14, 2026

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pavelsavara added 2 commits June 14, 2026 15:46

improve runtimeKeepalivePop()

151ecdd

WASM_BIGINT feedback

10a3963

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Comment thread src/coreclr/hosts/corerun/CMakeLists.txt Outdated

Comment thread eng/native.wasm.targets

Comment thread src/coreclr/runtime.proj Outdated

pavelsavara changed the title ~~[browser][wasm] Prep changes ahead of the emsdk 5.0.6 / LLVM 23 toolchain bump~~ [browser][wasm] Prep changes ahead of emsdk bump Jun 14, 2026

pavelsavara added 2 commits June 14, 2026 16:26

Merge branch 'main' into emsdk-upgrade-prep

eac18a9

cleanup

0bc6b22

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feedback

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Comment thread src/coreclr/hosts/corerun/CMakeLists.txt

Comment thread src/coreclr/hosts/corerun/CMakeLists.txt

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Copilot AI review requested due to automatic review settings June 14, 2026 17:43

pavelsavara force-pushed the emsdk-upgrade-prep branch from 4a68a47 to 2dde4e9 Compare June 14, 2026 17:43

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pavelsavara merged commit 98bfa17 into dotnet:main Jun 14, 2026
179 of 197 checks passed

pavelsavara deleted the emsdk-upgrade-prep branch June 14, 2026 20:17

dotnet-maestro Bot mentioned this pull request Jun 15, 2026

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

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build-analysis Bot mentioned this pull request Jun 15, 2026

MSBuild crashing in the build #92290

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pavelsavara commented Jun 14, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

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Summary

What's included

1. Browser version bump — Firefox / GeckoDriver

2. Keepalive / timer balance fixes (runtime bug fixes)

3. Disable WASM_BIGINT for corerun / Node (DWARF debugger workaround)

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pavelsavara commented Jun 14, 2026

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pavelsavara commented Jun 14, 2026 •

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3. Disable `WASM_BIGINT` for corerun / Node (DWARF debugger workaround)