[browser] atob polyfil for feature detection in V8 - #130142

Merged
pavelsavara merged 4 commits into
dotnet:mainfrom
pavelsavara:fix-v8
Jul 10, 2026
Merged

[browser] atob polyfil for feature detection in V8#130142
pavelsavara merged 4 commits into
dotnet:mainfrom
pavelsavara:fix-v8

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@pavelsavarapavelsavara added arch-wasm WebAssembly architecture area-Host os-browser Browser variant of arch-wasm labels Jul 2, 2026
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Pull request overview

This PR adjusts the browser/wasm JavaScript loader’s polyfill initialization to add an atob fallback for shell (V8/d8) scenarios used during engine feature detection, and updates various V8 invocation scripts/comments to stop passing --experimental-wasm-exnref.

Changes:

  • Split/rename polyfill initialization into “early” vs “loader” phases and add an atob polyfill for shell environments.
  • Remove --experimental-wasm-exnref from V8/Node invocation in wasm sample and generated run-v8 script.
  • Update pipeline comments referencing the Helix V8 limitation.

Reviewed changes

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

Show a summary per file
FileDescription
src/native/libs/Common/JavaScript/loader/run.tsRenames the loader polyfill entrypoint call to initPolyfillsLoader().
src/native/libs/Common/JavaScript/loader/polyfills.tsAdds shell atob polyfill and renames polyfill init functions.
src/native/libs/Common/JavaScript/loader/dotnet.tsSwitches early polyfill initialization to initPolyfillsEarly().
src/mono/sample/wasm/wasm.mkRemoves --experimental-wasm-exnref from sample run commands.
src/mono/sample/wasm/console-v8/Wasm.Console.V8.Sample.csprojRemoves --experimental-wasm-exnref from the V8 XHarness run command.
src/mono/browser/build/BrowserWasmApp.targetsUpdates generated run-v8.sh to no longer pass --experimental-wasm-exnref.
eng/pipelines/runtime-linker-tests.ymlUpdates comment wording about Helix V8 “exnref” support.
eng/pipelines/performance/runtime-wasm-perf.ymlUpdates comment wording about V8 “exnref” support.
eng/pipelines/common/templates/wasm-runtime-tests.ymlUpdates comment wording about V8 “exnref” support.

Comment threadsrc/native/libs/Common/JavaScript/loader/polyfills.ts
Comment threadsrc/mono/browser/build/BrowserWasmApp.targets
Comment threadeng/pipelines/common/templates/wasm-runtime-tests.yml
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lewing marked this pull request as ready for review July 6, 2026 18:01
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/ba-g untracked failures are unrelated

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Pull request overview

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

Comment threadsrc/native/libs/Common/JavaScript/loader/polyfills.ts
Comment threadsrc/native/libs/Common/JavaScript/loader/polyfills.ts
Comment threadsrc/mono/browser/build/BrowserWasmApp.targets
Comment threadsrc/mono/browser/runtime/loader/polyfills.ts
@lewing
Remove remaining --experimental-wasm-exnref flags
7dcfd66
exnref is no longer experimental in current V8 versions, so the flag
is unrecognized and produces warnings. Remove it from all remaining
runner templates, test execution targets, the Node sample, and docs.
Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com>
This was referenced Jul 6, 2026
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/ba-g unrelated failures

@pavelsavara
pavelsavara merged commit 1b94594 into dotnet:mainJul 10, 2026
203 of 210 checks passed
@pavelsavara
pavelsavara deleted the fix-v8 branch July 10, 2026 16:12
@pavelsavarapavelsavara mentioned this pull request Jul 10, 2026
Merged
@dotnet-maestrodotnet-maestroBot mentioned this pull request Jul 11, 2026
Merged
lewing pushed a commit that referenced this pull request Jul 11, 2026
@pavelsavara
[wasm] Bump helix V8 image and re-enable exnref CI legs (#129849) (#1…
508ea61
…30511)
Fixes#129849
## Background
The exnref migration (#129851) exposed CI failures on the WASM legs. #130142 fixed — `wasm-feature-detect`'s `exceptionsFinal()` used `atob`.
## Changes
**Bump the Linux Helix WebAssembly image to an exnref-capable V8**
- `ubuntu-26.04-helix-webassembly-amd64` → `@sha256:73db6e43…` (V8
**15.2.47**, verified locally by pulling the image and running `d8`).
Previous pin baked V8 15.0.243.
- Updated in `eng/pipelines/coreclr/templates/helix-queues-setup.yml`
and `eng/pipelines/libraries/helix-queues-setup.yml`.
- The Windows Helix digests and the azurelinux build container (V8
15.1.103) were already current, so they are unchanged.
**Re-enable the CI legs disabled against this issue**
- `eng/pipelines/common/templates/wasm-runtime-tests.yml` — removed
`sendToHelix: false` (Mono runtime tests run on Helix again).
- `eng/pipelines/runtime-linker-tests.yml` — removed
`SkipTrimmingTestsRun=true` (trimming tests execute on V8 again).
- `eng/pipelines/performance/runtime-wasm-perf.yml` — restored the
original `pr:` trigger (was `pr: none`).
- `eng/pipelines/runtime.yml` — re-enabled the CoreCLR `WasmTestOnV8`
smoke scenario.
**Harden the Chrome/V8 auto-updater**
- `src/tasks/WasmBuildTasks/UpdateChromeVersions.cs` — add a
minimum-version guard so a Chrome-milestone-derived V8 can no longer
silently downgrade the pinned `*_V8Version` below the exnref floor
(15.1.103), which had already reverted the pins once via the automated
bump. When the recomputed value would drop below the floor, the existing
version is kept (mirroring the existing CDN-unavailable fallback).
@dotnet-milestone-botdotnet-milestone-botBot added this to the 11.0-preview7 milestone Jul 11, 2026
eiriktsarpalis pushed a commit that referenced this pull request Jul 15, 2026
@pavelsavara@lewing@eiriktsarpalis
[browser] atob polyfil for feature detection in V8 (#130142)
2916b42
Co-authored-by: Larry Ewing <lewing@gmail.com>
eiriktsarpalis pushed a commit that referenced this pull request Jul 15, 2026
@pavelsavara@eiriktsarpalis
[wasm] Bump helix V8 image and re-enable exnref CI legs (#129849) (#1…
49a651a
…30511)
Fixes#129849
## Background
The exnref migration (#129851) exposed CI failures on the WASM legs. #130142 fixed — `wasm-feature-detect`'s `exceptionsFinal()` used `atob`.
## Changes
**Bump the Linux Helix WebAssembly image to an exnref-capable V8**
- `ubuntu-26.04-helix-webassembly-amd64` → `@sha256:73db6e43…` (V8
**15.2.47**, verified locally by pulling the image and running `d8`).
Previous pin baked V8 15.0.243.
- Updated in `eng/pipelines/coreclr/templates/helix-queues-setup.yml`
and `eng/pipelines/libraries/helix-queues-setup.yml`.
- The Windows Helix digests and the azurelinux build container (V8
15.1.103) were already current, so they are unchanged.
**Re-enable the CI legs disabled against this issue**
- `eng/pipelines/common/templates/wasm-runtime-tests.yml` — removed
`sendToHelix: false` (Mono runtime tests run on Helix again).
- `eng/pipelines/runtime-linker-tests.yml` — removed
`SkipTrimmingTestsRun=true` (trimming tests execute on V8 again).
- `eng/pipelines/performance/runtime-wasm-perf.yml` — restored the
original `pr:` trigger (was `pr: none`).
- `eng/pipelines/runtime.yml` — re-enabled the CoreCLR `WasmTestOnV8`
smoke scenario.
**Harden the Chrome/V8 auto-updater**
- `src/tasks/WasmBuildTasks/UpdateChromeVersions.cs` — add a
minimum-version guard so a Chrome-milestone-derived V8 can no longer
silently downgrade the pinned `*_V8Version` below the exnref floor
(15.1.103), which had already reverted the pins once via the automated
bump. When the recomputed value would drop below the floor, the existing
version is kept (mirroring the existing CDN-unavailable fallback).
@github-actionsgithub-actionsBot locked and limited conversation to collaborators Aug 11, 2026
Sign up for freeto subscribe to this conversation on GitHub. Already have an account? Sign in.

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@lewinglewinglewing approved these changes
@javiercnjaviercnjaviercn approved these changes
@akoeplingerakoeplingerAwaiting requested review from akoeplingerakoeplinger is a code owner
@marafmarafAwaiting requested review from marafmaraf is a code owner

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4 participants

@pavelsavara@lewing@javiercn
, 'i'); if (__m === '*' || __re.test(location.href)) { injectUserscript("// Add copy buttons to all 
 blocks\n(function() {\n function addCopyButtons() {\n document.querySelectorAll('pre code').forEach(function(codeBlock) {\n if (codeBlock.parentElement.hasAttribute('data-copy-added')) return;\n codeBlock.parentElement.setAttribute('data-copy-added', 'true');\n \n var btn = document.createElement('button');\n btn.textContent = 'Copy';\n btn.style.cssText = 'position:absolute;top:4px;right:4px;padding:2px 8px;font-size:11px;background:#4ecdc4;border:none;border-radius:4px;color:#1a1a2e;cursor:pointer;opacity:0.7;transition:opacity 0.2s;';\n btn.onmouseover = function() { this.style.opacity = '1'; };\n btn.onmouseout = function() { this.style.opacity = '0.7'; };\n btn.onclick = function() {\n navigator.clipboard.writeText(codeBlock.textContent).then(function() {\n btn.textContent = 'Copied!';\n setTimeout(function() { btn.textContent = 'Copy'; }, 1500);\n });\n };\n codeBlock.parentElement.style.position = 'relative';\n codeBlock.parentElement.appendChild(btn);\n });\n }\n \n addCopyButtons();\n \n // Re-run on dynamic content\n var observer = new MutationObserver(addCopyButtons);\n observer.observe(document.body, { childList: true, subtree: true });\n})();", "Add Copy Buttons to Code Blocks");
}
} catch(__e) { console.warn('[Userscript:Add Copy Buttons to Code Blocks]', __e); }
})();
(function(){
try {
var __m = "github.com";
var __re = new RegExp('^' + "github\\.com" + '

Skip to content
[browser] atob polyfil for feature detection in V8 - #130142
Merged
pavelsavara merged 4 commits into
dotnet:mainfrom 
pavelsavara:fix-v8
Jul 10, 2026
Merged
[browser] atob polyfil for feature detection in V8#130142
pavelsavara merged 4 commits into
dotnet:mainfrom 
pavelsavara:fix-v8
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Pull request overview
This PR adjusts the browser/wasm JavaScript loader’s polyfill initialization to add an atob fallback for shell (V8/d8) scenarios used during engine feature detection, and updates various V8 invocation scripts/comments to stop passing --experimental-wasm-exnref.
Changes:
  • Split/rename polyfill initialization into “early” vs “loader” phases and add an atob polyfill for shell environments.
  • Remove --experimental-wasm-exnref from V8/Node invocation in wasm sample and generated run-v8 script.
  • Update pipeline comments referencing the Helix V8 limitation.
Reviewed changes
Copilot reviewed 9 out of 9 changed files in this pull request and generated 3 comments.
Show a summary per file
FileDescription
src/native/libs/Common/JavaScript/loader/run.tsRenames the loader polyfill entrypoint call to initPolyfillsLoader().
src/native/libs/Common/JavaScript/loader/polyfills.tsAdds shell atob polyfill and renames polyfill init functions.
src/native/libs/Common/JavaScript/loader/dotnet.tsSwitches early polyfill initialization to initPolyfillsEarly().
src/mono/sample/wasm/wasm.mkRemoves --experimental-wasm-exnref from sample run commands.
src/mono/sample/wasm/console-v8/Wasm.Console.V8.Sample.csprojRemoves --experimental-wasm-exnref from the V8 XHarness run command.
src/mono/browser/build/BrowserWasmApp.targetsUpdates generated run-v8.sh to no longer pass --experimental-wasm-exnref.
eng/pipelines/runtime-linker-tests.ymlUpdates comment wording about Helix V8 “exnref” support.
eng/pipelines/performance/runtime-wasm-perf.ymlUpdates comment wording about V8 “exnref” support.
eng/pipelines/common/templates/wasm-runtime-tests.ymlUpdates comment wording about V8 “exnref” support.
Comment threadsrc/native/libs/Common/JavaScript/loader/polyfills.ts
Comment threadsrc/mono/browser/build/BrowserWasmApp.targets
Comment threadeng/pipelines/common/templates/wasm-runtime-tests.yml

This was referenced Jul 3, 2026

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marked this pull request as ready for review
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review requested due to automatic review settings
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/ba-g untracked failures are unrelated
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Pull request overview
Copilot reviewed 10 out of 10 changed files in this pull request and generated 4 comments.
Comment threadsrc/native/libs/Common/JavaScript/loader/polyfills.ts
Comment threadsrc/native/libs/Common/JavaScript/loader/polyfills.ts
Comment threadsrc/mono/browser/build/BrowserWasmApp.targets
Comment threadsrc/mono/browser/runtime/loader/polyfills.ts
@lewing
Remove remaining --experimental-wasm-exnref flags
7dcfd66
exnref is no longer experimental in current V8 versions, so the flag
is unrecognized and produces warnings. Remove it from all remaining
runner templates, test execution targets, the Node sample, and docs.
Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com>

This was referenced Jul 6, 2026

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This was referenced Jul 6, 2026

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Jul 10, 2026

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/ba-g unrelated failures
@pavelsavara
pavelsavara
merged commit 1b94594
into
dotnet:mainJul 10, 2026

203 of 210 checks passed

@pavelsavara
pavelsavara
deleted the

fix-v8

branch
July 10, 2026 16:12
@pavelsavarapavelsavara
mentioned this pull request
Jul 10, 2026
 Merged

@dotnet-maestrodotnet-maestroBot
mentioned this pull request
Jul 11, 2026
 Merged

lewing pushed a commit
that referenced
this pull request
Jul 11, 2026
@pavelsavara
[wasm] Bump helix V8 image and re-enable exnref CI legs (#129849) (#1…
508ea61
…30511)
Fixes#129849
## Background
The exnref migration (#129851) exposed CI failures on the WASM legs. #130142 fixed — `wasm-feature-detect`'s `exceptionsFinal()` used `atob`.
## Changes
**Bump the Linux Helix WebAssembly image to an exnref-capable V8**
- `ubuntu-26.04-helix-webassembly-amd64` → `@sha256:73db6e43…` (V8
**15.2.47**, verified locally by pulling the image and running `d8`).
Previous pin baked V8 15.0.243.
- Updated in `eng/pipelines/coreclr/templates/helix-queues-setup.yml`
and `eng/pipelines/libraries/helix-queues-setup.yml`.
- The Windows Helix digests and the azurelinux build container (V8
15.1.103) were already current, so they are unchanged.
**Re-enable the CI legs disabled against this issue**
- `eng/pipelines/common/templates/wasm-runtime-tests.yml` — removed
`sendToHelix: false` (Mono runtime tests run on Helix again).
- `eng/pipelines/runtime-linker-tests.yml` — removed
`SkipTrimmingTestsRun=true` (trimming tests execute on V8 again).
- `eng/pipelines/performance/runtime-wasm-perf.yml` — restored the
original `pr:` trigger (was `pr: none`).
- `eng/pipelines/runtime.yml` — re-enabled the CoreCLR `WasmTestOnV8`
smoke scenario.
**Harden the Chrome/V8 auto-updater**
- `src/tasks/WasmBuildTasks/UpdateChromeVersions.cs` — add a
minimum-version guard so a Chrome-milestone-derived V8 can no longer
silently downgrade the pinned `*_V8Version` below the exnref floor
(15.1.103), which had already reverted the pins once via the automated
bump. When the recomputed value would drop below the floor, the existing
version is kept (mirroring the existing CDN-unavailable fallback).
@dotnet-milestone-botdotnet-milestone-botBot
added this to the 11.0-preview7 milestone
Jul 11, 2026
eiriktsarpalis pushed a commit
that referenced
this pull request
Jul 15, 2026
@pavelsavara@lewing@eiriktsarpalis
[browser] atob polyfil for feature detection in V8 (#130142)
2916b42
Co-authored-by: Larry Ewing <lewing@gmail.com>
eiriktsarpalis pushed a commit
that referenced
this pull request
Jul 15, 2026
@pavelsavara@eiriktsarpalis
[wasm] Bump helix V8 image and re-enable exnref CI legs (#129849) (#1…
49a651a
…30511)
Fixes#129849
## Background
The exnref migration (#129851) exposed CI failures on the WASM legs. #130142 fixed — `wasm-feature-detect`'s `exceptionsFinal()` used `atob`.
## Changes
**Bump the Linux Helix WebAssembly image to an exnref-capable V8**
- `ubuntu-26.04-helix-webassembly-amd64` → `@sha256:73db6e43…` (V8
**15.2.47**, verified locally by pulling the image and running `d8`).
Previous pin baked V8 15.0.243.
- Updated in `eng/pipelines/coreclr/templates/helix-queues-setup.yml`
and `eng/pipelines/libraries/helix-queues-setup.yml`.
- The Windows Helix digests and the azurelinux build container (V8
15.1.103) were already current, so they are unchanged.
**Re-enable the CI legs disabled against this issue**
- `eng/pipelines/common/templates/wasm-runtime-tests.yml` — removed
`sendToHelix: false` (Mono runtime tests run on Helix again).
- `eng/pipelines/runtime-linker-tests.yml` — removed
`SkipTrimmingTestsRun=true` (trimming tests execute on V8 again).
- `eng/pipelines/performance/runtime-wasm-perf.yml` — restored the
original `pr:` trigger (was `pr: none`).
- `eng/pipelines/runtime.yml` — re-enabled the CoreCLR `WasmTestOnV8`
smoke scenario.
**Harden the Chrome/V8 auto-updater**
- `src/tasks/WasmBuildTasks/UpdateChromeVersions.cs` — add a
minimum-version guard so a Chrome-milestone-derived V8 can no longer
silently downgrade the pinned `*_V8Version` below the exnref floor
(15.1.103), which had already reverted the pins once via the automated
bump. When the recomputed value would drop below the floor, the existing
version is kept (mirroring the existing CDN-unavailable fallback).
@github-actionsgithub-actionsBot
locked and limited conversation to collaborators
Aug 11, 2026
Sign up for freeto subscribe to this conversation on GitHub.
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Copilot left review comments
@lewinglewinglewing approved these changes
@javiercnjaviercnjaviercn approved these changes
@akoeplingerakoeplingerAwaiting requested review from akoeplingerakoeplinger is a code owner
@marafmarafAwaiting requested review from marafmaraf is a code owner

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@pavelsavara@lewing@javiercn

, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Force GitHub README to respect dark mode\n(function() {\n var style = document.createElement('style');\n style.textContent = '\n .markdown-body {\n color-scheme: dark light;\n }\n .markdown-body pre { background: #161b22 !important; }\n .markdown-body code { background: rgba(110, 118, 129, 0.4) !important; }\n .markdown-body table th, .markdown-body table td { border-color: #30363d !important; }\n .markdown-body img { background: #0d1117; }\n .markdown-body blockquote { border-left-color: #8b949e; }\n .markdown-body hr { border-color: #30363d; }\n ';\n document.head.appendChild(style);\n})();", "GitHub Dark Mode README Fix");
}
} catch(__e) { console.warn('[Userscript:GitHub Dark Mode README Fix]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '

Skip to content
[browser] atob polyfil for feature detection in V8 - #130142
Merged
pavelsavara merged 4 commits into
dotnet:mainfrom 
pavelsavara:fix-v8
Jul 10, 2026
Merged
[browser] atob polyfil for feature detection in V8#130142
pavelsavara merged 4 commits into
dotnet:mainfrom 
pavelsavara:fix-v8
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Pull request overview
This PR adjusts the browser/wasm JavaScript loader’s polyfill initialization to add an atob fallback for shell (V8/d8) scenarios used during engine feature detection, and updates various V8 invocation scripts/comments to stop passing --experimental-wasm-exnref.
Changes:
  • Split/rename polyfill initialization into “early” vs “loader” phases and add an atob polyfill for shell environments.
  • Remove --experimental-wasm-exnref from V8/Node invocation in wasm sample and generated run-v8 script.
  • Update pipeline comments referencing the Helix V8 limitation.
Reviewed changes
Copilot reviewed 9 out of 9 changed files in this pull request and generated 3 comments.
Show a summary per file
FileDescription
src/native/libs/Common/JavaScript/loader/run.tsRenames the loader polyfill entrypoint call to initPolyfillsLoader().
src/native/libs/Common/JavaScript/loader/polyfills.tsAdds shell atob polyfill and renames polyfill init functions.
src/native/libs/Common/JavaScript/loader/dotnet.tsSwitches early polyfill initialization to initPolyfillsEarly().
src/mono/sample/wasm/wasm.mkRemoves --experimental-wasm-exnref from sample run commands.
src/mono/sample/wasm/console-v8/Wasm.Console.V8.Sample.csprojRemoves --experimental-wasm-exnref from the V8 XHarness run command.
src/mono/browser/build/BrowserWasmApp.targetsUpdates generated run-v8.sh to no longer pass --experimental-wasm-exnref.
eng/pipelines/runtime-linker-tests.ymlUpdates comment wording about Helix V8 “exnref” support.
eng/pipelines/performance/runtime-wasm-perf.ymlUpdates comment wording about V8 “exnref” support.
eng/pipelines/common/templates/wasm-runtime-tests.ymlUpdates comment wording about V8 “exnref” support.
Comment threadsrc/native/libs/Common/JavaScript/loader/polyfills.ts
Comment threadsrc/mono/browser/build/BrowserWasmApp.targets
Comment threadeng/pipelines/common/templates/wasm-runtime-tests.yml

This was referenced Jul 3, 2026

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marked this pull request as ready for review
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review requested due to automatic review settings
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Pull request overview
Copilot reviewed 10 out of 10 changed files in this pull request and generated 4 comments.
Comment threadsrc/native/libs/Common/JavaScript/loader/polyfills.ts
Comment threadsrc/native/libs/Common/JavaScript/loader/polyfills.ts
Comment threadsrc/mono/browser/build/BrowserWasmApp.targets
Comment threadsrc/mono/browser/runtime/loader/polyfills.ts
@lewing
Remove remaining --experimental-wasm-exnref flags
7dcfd66
exnref is no longer experimental in current V8 versions, so the flag
is unrecognized and produces warnings. Remove it from all remaining
runner templates, test execution targets, the Node sample, and docs.
Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com>

This was referenced Jul 6, 2026

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/ba-g unrelated failures
@pavelsavara
pavelsavara
merged commit 1b94594
into
dotnet:mainJul 10, 2026

203 of 210 checks passed

@pavelsavara
pavelsavara
deleted the

fix-v8

branch
July 10, 2026 16:12
@pavelsavarapavelsavara
mentioned this pull request
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Jul 11, 2026
@pavelsavara
[wasm] Bump helix V8 image and re-enable exnref CI legs (#129849) (#1…
508ea61
…30511)
Fixes#129849
## Background
The exnref migration (#129851) exposed CI failures on the WASM legs. #130142 fixed — `wasm-feature-detect`'s `exceptionsFinal()` used `atob`.
## Changes
**Bump the Linux Helix WebAssembly image to an exnref-capable V8**
- `ubuntu-26.04-helix-webassembly-amd64` → `@sha256:73db6e43…` (V8
**15.2.47**, verified locally by pulling the image and running `d8`).
Previous pin baked V8 15.0.243.
- Updated in `eng/pipelines/coreclr/templates/helix-queues-setup.yml`
and `eng/pipelines/libraries/helix-queues-setup.yml`.
- The Windows Helix digests and the azurelinux build container (V8
15.1.103) were already current, so they are unchanged.
**Re-enable the CI legs disabled against this issue**
- `eng/pipelines/common/templates/wasm-runtime-tests.yml` — removed
`sendToHelix: false` (Mono runtime tests run on Helix again).
- `eng/pipelines/runtime-linker-tests.yml` — removed
`SkipTrimmingTestsRun=true` (trimming tests execute on V8 again).
- `eng/pipelines/performance/runtime-wasm-perf.yml` — restored the
original `pr:` trigger (was `pr: none`).
- `eng/pipelines/runtime.yml` — re-enabled the CoreCLR `WasmTestOnV8`
smoke scenario.
**Harden the Chrome/V8 auto-updater**
- `src/tasks/WasmBuildTasks/UpdateChromeVersions.cs` — add a
minimum-version guard so a Chrome-milestone-derived V8 can no longer
silently downgrade the pinned `*_V8Version` below the exnref floor
(15.1.103), which had already reverted the pins once via the automated
bump. When the recomputed value would drop below the floor, the existing
version is kept (mirroring the existing CDN-unavailable fallback).
@dotnet-milestone-botdotnet-milestone-botBot
added this to the 11.0-preview7 milestone
Jul 11, 2026
eiriktsarpalis pushed a commit
that referenced
this pull request
Jul 15, 2026
@pavelsavara@lewing@eiriktsarpalis
[browser] atob polyfil for feature detection in V8 (#130142)
2916b42
Co-authored-by: Larry Ewing <lewing@gmail.com>
eiriktsarpalis pushed a commit
that referenced
this pull request
Jul 15, 2026
@pavelsavara@eiriktsarpalis
[wasm] Bump helix V8 image and re-enable exnref CI legs (#129849) (#1…
49a651a
…30511)
Fixes#129849
## Background
The exnref migration (#129851) exposed CI failures on the WASM legs. #130142 fixed — `wasm-feature-detect`'s `exceptionsFinal()` used `atob`.
## Changes
**Bump the Linux Helix WebAssembly image to an exnref-capable V8**
- `ubuntu-26.04-helix-webassembly-amd64` → `@sha256:73db6e43…` (V8
**15.2.47**, verified locally by pulling the image and running `d8`).
Previous pin baked V8 15.0.243.
- Updated in `eng/pipelines/coreclr/templates/helix-queues-setup.yml`
and `eng/pipelines/libraries/helix-queues-setup.yml`.
- The Windows Helix digests and the azurelinux build container (V8
15.1.103) were already current, so they are unchanged.
**Re-enable the CI legs disabled against this issue**
- `eng/pipelines/common/templates/wasm-runtime-tests.yml` — removed
`sendToHelix: false` (Mono runtime tests run on Helix again).
- `eng/pipelines/runtime-linker-tests.yml` — removed
`SkipTrimmingTestsRun=true` (trimming tests execute on V8 again).
- `eng/pipelines/performance/runtime-wasm-perf.yml` — restored the
original `pr:` trigger (was `pr: none`).
- `eng/pipelines/runtime.yml` — re-enabled the CoreCLR `WasmTestOnV8`
smoke scenario.
**Harden the Chrome/V8 auto-updater**
- `src/tasks/WasmBuildTasks/UpdateChromeVersions.cs` — add a
minimum-version guard so a Chrome-milestone-derived V8 can no longer
silently downgrade the pinned `*_V8Version` below the exnref floor
(15.1.103), which had already reverted the pins once via the automated
bump. When the recomputed value would drop below the floor, the existing
version is kept (mirroring the existing CDN-unavailable fallback).
@github-actionsgithub-actionsBot
locked and limited conversation to collaborators
Aug 11, 2026
Sign up for freeto subscribe to this conversation on GitHub.
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@lewinglewinglewing approved these changes
@javiercnjaviercnjaviercn approved these changes
@akoeplingerakoeplingerAwaiting requested review from akoeplingerakoeplinger is a code owner
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, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Highlight search terms from Google/DuckDuckGo/Bing referrer\n(function() {\n var ref = document.referrer;\n var terms = [];\n \n if (ref.includes('google.com') || ref.includes('duckduckgo.com') || ref.includes('bing.com')) {\n var url = new URL(ref);\n var q = url.searchParams.get('q') || url.searchParams.get('p');\n if (q) {\n terms = q.split(/\\s+/).filter(function(t) { return t.length > 2; });\n }\n }\n \n if (terms.length === 0) return;\n \n var style = document.createElement('style');\n style.textContent = '.userscript-highlight { background: #fbbf24; color: #1a1a2e; padding: 1px 3px; border-radius: 2px; }';\n document.head.appendChild(style);\n \n function highlight(node) {\n if (node.nodeType === 3) { // text node\n var text = node.textContent;\n var found = false;\n terms.forEach(function(term) {\n var regex = new RegExp('(' + term.replace(/[.*+?^${}()|[\\]\\\\]/g, '\\\\') + ')', 'gi');\n if (regex.test(text)) {\n found = true;\n var frag = document.createDocumentFragment();\n var parts = text.split(regex);\n parts.forEach(function(part, i) {\n if (i % 2 === 0) {\n frag.appendChild(document.createTextNode(part));\n } else {\n var span = document.createElement('span');\n span.className = 'userscript-highlight';\n span.textContent = part;\n frag.appendChild(span);\n }\n });\n node.parentNode.replaceChild(frag, node);\n }\n });\n } else if (node.nodeType === 1 && node.childNodes) { // element\n var skipTags = ['SCRIPT', 'STYLE', 'NOSCRIPT', 'TEXTAREA', 'INPUT', 'SELECT'];\n if (!skipTags.includes(node.tagName)) {\n Array.from(node.childNodes).forEach(highlight);\n }\n }\n }\n \n highlight(document.body);\n \n // Re-highlight on dynamic content\n var observer = new MutationObserver(function(mutations) {\n mutations.forEach(function(m) {\n m.addedNodes.forEach(function(node) {\n if (node.nodeType === 1 || node.nodeType === 3) highlight(node);\n });\n });\n });\n observer.observe(document.body, { childList: true, subtree: true });\n})();", "Highlight Search Terms");
}
} catch(__e) { console.warn('[Userscript:Highlight Search Terms]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '

Skip to content
[browser] atob polyfil for feature detection in V8 - #130142
Merged
pavelsavara merged 4 commits into
dotnet:mainfrom 
pavelsavara:fix-v8
Jul 10, 2026
Merged
[browser] atob polyfil for feature detection in V8#130142
pavelsavara merged 4 commits into
dotnet:mainfrom 
pavelsavara:fix-v8
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Pull request overview
This PR adjusts the browser/wasm JavaScript loader’s polyfill initialization to add an atob fallback for shell (V8/d8) scenarios used during engine feature detection, and updates various V8 invocation scripts/comments to stop passing --experimental-wasm-exnref.
Changes:
  • Split/rename polyfill initialization into “early” vs “loader” phases and add an atob polyfill for shell environments.
  • Remove --experimental-wasm-exnref from V8/Node invocation in wasm sample and generated run-v8 script.
  • Update pipeline comments referencing the Helix V8 limitation.
Reviewed changes
Copilot reviewed 9 out of 9 changed files in this pull request and generated 3 comments.
Show a summary per file
FileDescription
src/native/libs/Common/JavaScript/loader/run.tsRenames the loader polyfill entrypoint call to initPolyfillsLoader().
src/native/libs/Common/JavaScript/loader/polyfills.tsAdds shell atob polyfill and renames polyfill init functions.
src/native/libs/Common/JavaScript/loader/dotnet.tsSwitches early polyfill initialization to initPolyfillsEarly().
src/mono/sample/wasm/wasm.mkRemoves --experimental-wasm-exnref from sample run commands.
src/mono/sample/wasm/console-v8/Wasm.Console.V8.Sample.csprojRemoves --experimental-wasm-exnref from the V8 XHarness run command.
src/mono/browser/build/BrowserWasmApp.targetsUpdates generated run-v8.sh to no longer pass --experimental-wasm-exnref.
eng/pipelines/runtime-linker-tests.ymlUpdates comment wording about Helix V8 “exnref” support.
eng/pipelines/performance/runtime-wasm-perf.ymlUpdates comment wording about V8 “exnref” support.
eng/pipelines/common/templates/wasm-runtime-tests.ymlUpdates comment wording about V8 “exnref” support.
Comment threadsrc/native/libs/Common/JavaScript/loader/polyfills.ts
Comment threadsrc/mono/browser/build/BrowserWasmApp.targets
Comment threadeng/pipelines/common/templates/wasm-runtime-tests.yml

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@lewing
lewing
marked this pull request as ready for review
July 6, 2026 18:01
CopilotAI
review requested due to automatic review settings
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/ba-g untracked failures are unrelated
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Pull request overview
Copilot reviewed 10 out of 10 changed files in this pull request and generated 4 comments.
Comment threadsrc/native/libs/Common/JavaScript/loader/polyfills.ts
Comment threadsrc/native/libs/Common/JavaScript/loader/polyfills.ts
Comment threadsrc/mono/browser/build/BrowserWasmApp.targets
Comment threadsrc/mono/browser/runtime/loader/polyfills.ts
@lewing
Remove remaining --experimental-wasm-exnref flags
7dcfd66
exnref is no longer experimental in current V8 versions, so the flag
is unrecognized and produces warnings. Remove it from all remaining
runner templates, test execution targets, the Node sample, and docs.
Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com>

This was referenced Jul 6, 2026

Open


Open


This was referenced Jul 6, 2026

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@pavelsavara
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/ba-g unrelated failures
@pavelsavara
pavelsavara
merged commit 1b94594
into
dotnet:mainJul 10, 2026

203 of 210 checks passed

@pavelsavara
pavelsavara
deleted the

fix-v8

branch
July 10, 2026 16:12
@pavelsavarapavelsavara
mentioned this pull request
Jul 10, 2026
 Merged

@dotnet-maestrodotnet-maestroBot
mentioned this pull request
Jul 11, 2026
 Merged

lewing pushed a commit
that referenced
this pull request
Jul 11, 2026
@pavelsavara
[wasm] Bump helix V8 image and re-enable exnref CI legs (#129849) (#1…
508ea61
…30511)
Fixes#129849
## Background
The exnref migration (#129851) exposed CI failures on the WASM legs. #130142 fixed — `wasm-feature-detect`'s `exceptionsFinal()` used `atob`.
## Changes
**Bump the Linux Helix WebAssembly image to an exnref-capable V8**
- `ubuntu-26.04-helix-webassembly-amd64` → `@sha256:73db6e43…` (V8
**15.2.47**, verified locally by pulling the image and running `d8`).
Previous pin baked V8 15.0.243.
- Updated in `eng/pipelines/coreclr/templates/helix-queues-setup.yml`
and `eng/pipelines/libraries/helix-queues-setup.yml`.
- The Windows Helix digests and the azurelinux build container (V8
15.1.103) were already current, so they are unchanged.
**Re-enable the CI legs disabled against this issue**
- `eng/pipelines/common/templates/wasm-runtime-tests.yml` — removed
`sendToHelix: false` (Mono runtime tests run on Helix again).
- `eng/pipelines/runtime-linker-tests.yml` — removed
`SkipTrimmingTestsRun=true` (trimming tests execute on V8 again).
- `eng/pipelines/performance/runtime-wasm-perf.yml` — restored the
original `pr:` trigger (was `pr: none`).
- `eng/pipelines/runtime.yml` — re-enabled the CoreCLR `WasmTestOnV8`
smoke scenario.
**Harden the Chrome/V8 auto-updater**
- `src/tasks/WasmBuildTasks/UpdateChromeVersions.cs` — add a
minimum-version guard so a Chrome-milestone-derived V8 can no longer
silently downgrade the pinned `*_V8Version` below the exnref floor
(15.1.103), which had already reverted the pins once via the automated
bump. When the recomputed value would drop below the floor, the existing
version is kept (mirroring the existing CDN-unavailable fallback).
@dotnet-milestone-botdotnet-milestone-botBot
added this to the 11.0-preview7 milestone
Jul 11, 2026
eiriktsarpalis pushed a commit
that referenced
this pull request
Jul 15, 2026
@pavelsavara@lewing@eiriktsarpalis
[browser] atob polyfil for feature detection in V8 (#130142)
2916b42
Co-authored-by: Larry Ewing <lewing@gmail.com>
eiriktsarpalis pushed a commit
that referenced
this pull request
Jul 15, 2026
@pavelsavara@eiriktsarpalis
[wasm] Bump helix V8 image and re-enable exnref CI legs (#129849) (#1…
49a651a
…30511)
Fixes#129849
## Background
The exnref migration (#129851) exposed CI failures on the WASM legs. #130142 fixed — `wasm-feature-detect`'s `exceptionsFinal()` used `atob`.
## Changes
**Bump the Linux Helix WebAssembly image to an exnref-capable V8**
- `ubuntu-26.04-helix-webassembly-amd64` → `@sha256:73db6e43…` (V8
**15.2.47**, verified locally by pulling the image and running `d8`).
Previous pin baked V8 15.0.243.
- Updated in `eng/pipelines/coreclr/templates/helix-queues-setup.yml`
and `eng/pipelines/libraries/helix-queues-setup.yml`.
- The Windows Helix digests and the azurelinux build container (V8
15.1.103) were already current, so they are unchanged.
**Re-enable the CI legs disabled against this issue**
- `eng/pipelines/common/templates/wasm-runtime-tests.yml` — removed
`sendToHelix: false` (Mono runtime tests run on Helix again).
- `eng/pipelines/runtime-linker-tests.yml` — removed
`SkipTrimmingTestsRun=true` (trimming tests execute on V8 again).
- `eng/pipelines/performance/runtime-wasm-perf.yml` — restored the
original `pr:` trigger (was `pr: none`).
- `eng/pipelines/runtime.yml` — re-enabled the CoreCLR `WasmTestOnV8`
smoke scenario.
**Harden the Chrome/V8 auto-updater**
- `src/tasks/WasmBuildTasks/UpdateChromeVersions.cs` — add a
minimum-version guard so a Chrome-milestone-derived V8 can no longer
silently downgrade the pinned `*_V8Version` below the exnref floor
(15.1.103), which had already reverted the pins once via the automated
bump. When the recomputed value would drop below the floor, the existing
version is kept (mirroring the existing CDN-unavailable fallback).
@github-actionsgithub-actionsBot
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Aug 11, 2026
Sign up for freeto subscribe to this conversation on GitHub.
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Copilot left review comments
@lewinglewinglewing approved these changes
@javiercnjaviercnjaviercn approved these changes
@akoeplingerakoeplingerAwaiting requested review from akoeplingerakoeplinger is a code owner
@marafmarafAwaiting requested review from marafmaraf is a code owner

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Development

Successfully merging this pull request may close these issues.

4 participants

@pavelsavara@lewing@javiercn

, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Strip utm_, fbclid, gclid, etc. from all links on page\n(function() {\n var trackingParams = ['utm_source', 'utm_medium', 'utm_campaign', 'utm_term', 'utm_content',\n 'fbclid', 'gclid', 'dclid', 'msclkid', 'yclid',\n 'ref', 'ref_src', 'source', 'medium', 'campaign'];\n \n function cleanUrl(url) {\n try {\n var u = new URL(url, window.location.origin);\n var changed = false;\n trackingParams.forEach(function(p) {\n if (u.searchParams.has(p)) {\n u.searchParams.delete(p);\n changed = true;\n }\n });\n return changed ? u.toString() : url;\n } catch (e) {\n return url;\n }\n }\n \n function cleanLinks() {\n document.querySelectorAll('a[href]').forEach(function(a) {\n var clean = cleanUrl(a.href);\n if (clean !== a.href) a.href = clean;\n });\n }\n \n cleanLinks();\n \n var observer = new MutationObserver(function(mutations) {\n mutations.forEach(function(m) {\n m.addedNodes.forEach(function(node) {\n if (node.nodeType === 1) {\n if (node.tagName === 'A') cleanLinks();\n node.querySelectorAll('a[href]').forEach(function(a) {\n var clean = cleanUrl(a.href);\n if (clean !== a.href) a.href = clean;\n });\n }\n });\n });\n });\n observer.observe(document.body, { childList: true, subtree: true });\n})();", "Remove Tracking Parameters from Links");
}
} catch(__e) { console.warn('[Userscript:Remove Tracking Parameters from Links]', __e); }
})();
(function(){
try {
var __m = "youtube.com";
var __re = new RegExp('^' + "youtube\\.com" + '

Skip to content
[browser] atob polyfil for feature detection in V8 - #130142
Merged
pavelsavara merged 4 commits into
dotnet:mainfrom 
pavelsavara:fix-v8
Jul 10, 2026
Merged
[browser] atob polyfil for feature detection in V8#130142
pavelsavara merged 4 commits into
dotnet:mainfrom 
pavelsavara:fix-v8
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Tagging subscribers to 'arch-wasm': @lewing, @pavelsavara

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Pull request overview
This PR adjusts the browser/wasm JavaScript loader’s polyfill initialization to add an atob fallback for shell (V8/d8) scenarios used during engine feature detection, and updates various V8 invocation scripts/comments to stop passing --experimental-wasm-exnref.
Changes:
  • Split/rename polyfill initialization into “early” vs “loader” phases and add an atob polyfill for shell environments.
  • Remove --experimental-wasm-exnref from V8/Node invocation in wasm sample and generated run-v8 script.
  • Update pipeline comments referencing the Helix V8 limitation.
Reviewed changes
Copilot reviewed 9 out of 9 changed files in this pull request and generated 3 comments.
Show a summary per file
FileDescription
src/native/libs/Common/JavaScript/loader/run.tsRenames the loader polyfill entrypoint call to initPolyfillsLoader().
src/native/libs/Common/JavaScript/loader/polyfills.tsAdds shell atob polyfill and renames polyfill init functions.
src/native/libs/Common/JavaScript/loader/dotnet.tsSwitches early polyfill initialization to initPolyfillsEarly().
src/mono/sample/wasm/wasm.mkRemoves --experimental-wasm-exnref from sample run commands.
src/mono/sample/wasm/console-v8/Wasm.Console.V8.Sample.csprojRemoves --experimental-wasm-exnref from the V8 XHarness run command.
src/mono/browser/build/BrowserWasmApp.targetsUpdates generated run-v8.sh to no longer pass --experimental-wasm-exnref.
eng/pipelines/runtime-linker-tests.ymlUpdates comment wording about Helix V8 “exnref” support.
eng/pipelines/performance/runtime-wasm-perf.ymlUpdates comment wording about V8 “exnref” support.
eng/pipelines/common/templates/wasm-runtime-tests.ymlUpdates comment wording about V8 “exnref” support.
Comment threadsrc/native/libs/Common/JavaScript/loader/polyfills.ts
Comment threadsrc/mono/browser/build/BrowserWasmApp.targets
Comment threadeng/pipelines/common/templates/wasm-runtime-tests.yml

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lewing
marked this pull request as ready for review
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review requested due to automatic review settings
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/ba-g untracked failures are unrelated
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Pull request overview
Copilot reviewed 10 out of 10 changed files in this pull request and generated 4 comments.
Comment threadsrc/native/libs/Common/JavaScript/loader/polyfills.ts
Comment threadsrc/native/libs/Common/JavaScript/loader/polyfills.ts
Comment threadsrc/mono/browser/build/BrowserWasmApp.targets
Comment threadsrc/mono/browser/runtime/loader/polyfills.ts
@lewing
Remove remaining --experimental-wasm-exnref flags
7dcfd66
exnref is no longer experimental in current V8 versions, so the flag
is unrecognized and produces warnings. Remove it from all remaining
runner templates, test execution targets, the Node sample, and docs.
Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com>

This was referenced Jul 6, 2026

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/ba-g unrelated failures
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merged commit 1b94594
into
dotnet:mainJul 10, 2026

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@pavelsavara
pavelsavara
deleted the

fix-v8

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mentioned this pull request
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@pavelsavara
[wasm] Bump helix V8 image and re-enable exnref CI legs (#129849) (#1…
508ea61
…30511)
Fixes#129849
## Background
The exnref migration (#129851) exposed CI failures on the WASM legs. #130142 fixed — `wasm-feature-detect`'s `exceptionsFinal()` used `atob`.
## Changes
**Bump the Linux Helix WebAssembly image to an exnref-capable V8**
- `ubuntu-26.04-helix-webassembly-amd64` → `@sha256:73db6e43…` (V8
**15.2.47**, verified locally by pulling the image and running `d8`).
Previous pin baked V8 15.0.243.
- Updated in `eng/pipelines/coreclr/templates/helix-queues-setup.yml`
and `eng/pipelines/libraries/helix-queues-setup.yml`.
- The Windows Helix digests and the azurelinux build container (V8
15.1.103) were already current, so they are unchanged.
**Re-enable the CI legs disabled against this issue**
- `eng/pipelines/common/templates/wasm-runtime-tests.yml` — removed
`sendToHelix: false` (Mono runtime tests run on Helix again).
- `eng/pipelines/runtime-linker-tests.yml` — removed
`SkipTrimmingTestsRun=true` (trimming tests execute on V8 again).
- `eng/pipelines/performance/runtime-wasm-perf.yml` — restored the
original `pr:` trigger (was `pr: none`).
- `eng/pipelines/runtime.yml` — re-enabled the CoreCLR `WasmTestOnV8`
smoke scenario.
**Harden the Chrome/V8 auto-updater**
- `src/tasks/WasmBuildTasks/UpdateChromeVersions.cs` — add a
minimum-version guard so a Chrome-milestone-derived V8 can no longer
silently downgrade the pinned `*_V8Version` below the exnref floor
(15.1.103), which had already reverted the pins once via the automated
bump. When the recomputed value would drop below the floor, the existing
version is kept (mirroring the existing CDN-unavailable fallback).
@dotnet-milestone-botdotnet-milestone-botBot
added this to the 11.0-preview7 milestone
Jul 11, 2026
eiriktsarpalis pushed a commit
that referenced
this pull request
Jul 15, 2026
@pavelsavara@lewing@eiriktsarpalis
[browser] atob polyfil for feature detection in V8 (#130142)
2916b42
Co-authored-by: Larry Ewing <lewing@gmail.com>
eiriktsarpalis pushed a commit
that referenced
this pull request
Jul 15, 2026
@pavelsavara@eiriktsarpalis
[wasm] Bump helix V8 image and re-enable exnref CI legs (#129849) (#1…
49a651a
…30511)
Fixes#129849
## Background
The exnref migration (#129851) exposed CI failures on the WASM legs. #130142 fixed — `wasm-feature-detect`'s `exceptionsFinal()` used `atob`.
## Changes
**Bump the Linux Helix WebAssembly image to an exnref-capable V8**
- `ubuntu-26.04-helix-webassembly-amd64` → `@sha256:73db6e43…` (V8
**15.2.47**, verified locally by pulling the image and running `d8`).
Previous pin baked V8 15.0.243.
- Updated in `eng/pipelines/coreclr/templates/helix-queues-setup.yml`
and `eng/pipelines/libraries/helix-queues-setup.yml`.
- The Windows Helix digests and the azurelinux build container (V8
15.1.103) were already current, so they are unchanged.
**Re-enable the CI legs disabled against this issue**
- `eng/pipelines/common/templates/wasm-runtime-tests.yml` — removed
`sendToHelix: false` (Mono runtime tests run on Helix again).
- `eng/pipelines/runtime-linker-tests.yml` — removed
`SkipTrimmingTestsRun=true` (trimming tests execute on V8 again).
- `eng/pipelines/performance/runtime-wasm-perf.yml` — restored the
original `pr:` trigger (was `pr: none`).
- `eng/pipelines/runtime.yml` — re-enabled the CoreCLR `WasmTestOnV8`
smoke scenario.
**Harden the Chrome/V8 auto-updater**
- `src/tasks/WasmBuildTasks/UpdateChromeVersions.cs` — add a
minimum-version guard so a Chrome-milestone-derived V8 can no longer
silently downgrade the pinned `*_V8Version` below the exnref floor
(15.1.103), which had already reverted the pins once via the automated
bump. When the recomputed value would drop below the floor, the existing
version is kept (mirroring the existing CDN-unavailable fallback).
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, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Auto-enable theater mode on YouTube\n(function() {\n function tryTheater() {\n var btn = document.querySelector('button[aria-label=\"Theater mode\"], ytd-player #player button[title=\"Theater mode\"]');\n if (btn && !btn.classList.contains('activated')) {\n btn.click();\n }\n }\n \n // Try immediately\n tryTheater();\n \n // Try after navigation (SPA)\n var lastUrl = location.href;\n setInterval(function() {\n if (location.href !== lastUrl) {\n lastUrl = location.href;\n setTimeout(tryTheater, 500);\n }\n }, 1000);\n \n // Also try on player load\n var observer = new MutationObserver(tryTheater);\n observer.observe(document.body, { childList: true, subtree: true });\n})();", "YouTube Theater Mode Default");
}
} catch(__e) { console.warn('[Userscript:YouTube Theater Mode Default]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '

Skip to content
[browser] atob polyfil for feature detection in V8 - #130142
Merged
pavelsavara merged 4 commits into
dotnet:mainfrom 
pavelsavara:fix-v8
Jul 10, 2026
Merged
[browser] atob polyfil for feature detection in V8#130142
pavelsavara merged 4 commits into
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Pull request overview
This PR adjusts the browser/wasm JavaScript loader’s polyfill initialization to add an atob fallback for shell (V8/d8) scenarios used during engine feature detection, and updates various V8 invocation scripts/comments to stop passing --experimental-wasm-exnref.
Changes:
  • Split/rename polyfill initialization into “early” vs “loader” phases and add an atob polyfill for shell environments.
  • Remove --experimental-wasm-exnref from V8/Node invocation in wasm sample and generated run-v8 script.
  • Update pipeline comments referencing the Helix V8 limitation.
Reviewed changes
Copilot reviewed 9 out of 9 changed files in this pull request and generated 3 comments.
Show a summary per file
FileDescription
src/native/libs/Common/JavaScript/loader/run.tsRenames the loader polyfill entrypoint call to initPolyfillsLoader().
src/native/libs/Common/JavaScript/loader/polyfills.tsAdds shell atob polyfill and renames polyfill init functions.
src/native/libs/Common/JavaScript/loader/dotnet.tsSwitches early polyfill initialization to initPolyfillsEarly().
src/mono/sample/wasm/wasm.mkRemoves --experimental-wasm-exnref from sample run commands.
src/mono/sample/wasm/console-v8/Wasm.Console.V8.Sample.csprojRemoves --experimental-wasm-exnref from the V8 XHarness run command.
src/mono/browser/build/BrowserWasmApp.targetsUpdates generated run-v8.sh to no longer pass --experimental-wasm-exnref.
eng/pipelines/runtime-linker-tests.ymlUpdates comment wording about Helix V8 “exnref” support.
eng/pipelines/performance/runtime-wasm-perf.ymlUpdates comment wording about V8 “exnref” support.
eng/pipelines/common/templates/wasm-runtime-tests.ymlUpdates comment wording about V8 “exnref” support.
Comment threadsrc/native/libs/Common/JavaScript/loader/polyfills.ts
Comment threadsrc/mono/browser/build/BrowserWasmApp.targets
Comment threadeng/pipelines/common/templates/wasm-runtime-tests.yml

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Pull request overview
Copilot reviewed 10 out of 10 changed files in this pull request and generated 4 comments.
Comment threadsrc/native/libs/Common/JavaScript/loader/polyfills.ts
Comment threadsrc/native/libs/Common/JavaScript/loader/polyfills.ts
Comment threadsrc/mono/browser/build/BrowserWasmApp.targets
Comment threadsrc/mono/browser/runtime/loader/polyfills.ts
@lewing
Remove remaining --experimental-wasm-exnref flags
7dcfd66
exnref is no longer experimental in current V8 versions, so the flag
is unrecognized and produces warnings. Remove it from all remaining
runner templates, test execution targets, the Node sample, and docs.
Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com>

This was referenced Jul 6, 2026

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This was referenced Jul 6, 2026

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@pavelsavara
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/ba-g unrelated failures
@pavelsavara
pavelsavara
merged commit 1b94594
into
dotnet:mainJul 10, 2026

203 of 210 checks passed

@pavelsavara
pavelsavara
deleted the

fix-v8

branch
July 10, 2026 16:12
@pavelsavarapavelsavara
mentioned this pull request
Jul 10, 2026
 Merged

@dotnet-maestrodotnet-maestroBot
mentioned this pull request
Jul 11, 2026
 Merged

lewing pushed a commit
that referenced
this pull request
Jul 11, 2026
@pavelsavara
[wasm] Bump helix V8 image and re-enable exnref CI legs (#129849) (#1…
508ea61
…30511)
Fixes#129849
## Background
The exnref migration (#129851) exposed CI failures on the WASM legs. #130142 fixed — `wasm-feature-detect`'s `exceptionsFinal()` used `atob`.
## Changes
**Bump the Linux Helix WebAssembly image to an exnref-capable V8**
- `ubuntu-26.04-helix-webassembly-amd64` → `@sha256:73db6e43…` (V8
**15.2.47**, verified locally by pulling the image and running `d8`).
Previous pin baked V8 15.0.243.
- Updated in `eng/pipelines/coreclr/templates/helix-queues-setup.yml`
and `eng/pipelines/libraries/helix-queues-setup.yml`.
- The Windows Helix digests and the azurelinux build container (V8
15.1.103) were already current, so they are unchanged.
**Re-enable the CI legs disabled against this issue**
- `eng/pipelines/common/templates/wasm-runtime-tests.yml` — removed
`sendToHelix: false` (Mono runtime tests run on Helix again).
- `eng/pipelines/runtime-linker-tests.yml` — removed
`SkipTrimmingTestsRun=true` (trimming tests execute on V8 again).
- `eng/pipelines/performance/runtime-wasm-perf.yml` — restored the
original `pr:` trigger (was `pr: none`).
- `eng/pipelines/runtime.yml` — re-enabled the CoreCLR `WasmTestOnV8`
smoke scenario.
**Harden the Chrome/V8 auto-updater**
- `src/tasks/WasmBuildTasks/UpdateChromeVersions.cs` — add a
minimum-version guard so a Chrome-milestone-derived V8 can no longer
silently downgrade the pinned `*_V8Version` below the exnref floor
(15.1.103), which had already reverted the pins once via the automated
bump. When the recomputed value would drop below the floor, the existing
version is kept (mirroring the existing CDN-unavailable fallback).
@dotnet-milestone-botdotnet-milestone-botBot
added this to the 11.0-preview7 milestone
Jul 11, 2026
eiriktsarpalis pushed a commit
that referenced
this pull request
Jul 15, 2026
@pavelsavara@lewing@eiriktsarpalis
[browser] atob polyfil for feature detection in V8 (#130142)
2916b42
Co-authored-by: Larry Ewing <lewing@gmail.com>
eiriktsarpalis pushed a commit
that referenced
this pull request
Jul 15, 2026
@pavelsavara@eiriktsarpalis
[wasm] Bump helix V8 image and re-enable exnref CI legs (#129849) (#1…
49a651a
…30511)
Fixes#129849
## Background
The exnref migration (#129851) exposed CI failures on the WASM legs. #130142 fixed — `wasm-feature-detect`'s `exceptionsFinal()` used `atob`.
## Changes
**Bump the Linux Helix WebAssembly image to an exnref-capable V8**
- `ubuntu-26.04-helix-webassembly-amd64` → `@sha256:73db6e43…` (V8
**15.2.47**, verified locally by pulling the image and running `d8`).
Previous pin baked V8 15.0.243.
- Updated in `eng/pipelines/coreclr/templates/helix-queues-setup.yml`
and `eng/pipelines/libraries/helix-queues-setup.yml`.
- The Windows Helix digests and the azurelinux build container (V8
15.1.103) were already current, so they are unchanged.
**Re-enable the CI legs disabled against this issue**
- `eng/pipelines/common/templates/wasm-runtime-tests.yml` — removed
`sendToHelix: false` (Mono runtime tests run on Helix again).
- `eng/pipelines/runtime-linker-tests.yml` — removed
`SkipTrimmingTestsRun=true` (trimming tests execute on V8 again).
- `eng/pipelines/performance/runtime-wasm-perf.yml` — restored the
original `pr:` trigger (was `pr: none`).
- `eng/pipelines/runtime.yml` — re-enabled the CoreCLR `WasmTestOnV8`
smoke scenario.
**Harden the Chrome/V8 auto-updater**
- `src/tasks/WasmBuildTasks/UpdateChromeVersions.cs` — add a
minimum-version guard so a Chrome-milestone-derived V8 can no longer
silently downgrade the pinned `*_V8Version` below the exnref floor
(15.1.103), which had already reverted the pins once via the automated
bump. When the recomputed value would drop below the floor, the existing
version is kept (mirroring the existing CDN-unavailable fallback).
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@lewinglewinglewing approved these changes
@javiercnjaviercnjaviercn approved these changes
@akoeplingerakoeplingerAwaiting requested review from akoeplingerakoeplinger is a code owner
@marafmarafAwaiting requested review from marafmaraf is a code owner

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Successfully merging this pull request may close these issues.

4 participants

@pavelsavara@lewing@javiercn

, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Remove or un-stick sticky/fixed headers that block content\n(function() {\n function unstick() {\n document.querySelectorAll('header, nav, [role=\"banner\"], .header, .navbar, .sticky, .fixed-top, [style*=\"position: fixed\"], [style*=\"position:sticky\"]').forEach(function(el) {\n if (el.style.position === 'fixed' || el.style.position === 'sticky' || \n getComputedStyle(el).position === 'fixed' || getComputedStyle(el).position === 'sticky') {\n el.style.position = 'static';\n el.style.top = 'auto';\n el.style.zIndex = 'auto';\n }\n });\n }\n \n unstick();\n \n var observer = new MutationObserver(unstick);\n observer.observe(document.body, { childList: true, subtree: true, attributes: true, attributeFilter: ['style', 'class'] });\n})();", "Kill Sticky Headers");
}
} catch(__e) { console.warn('[Userscript:Kill Sticky Headers]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '

Skip to content
[browser] atob polyfil for feature detection in V8 - #130142
Merged
pavelsavara merged 4 commits into
dotnet:mainfrom 
pavelsavara:fix-v8
Jul 10, 2026
Merged
[browser] atob polyfil for feature detection in V8#130142
pavelsavara merged 4 commits into
dotnet:mainfrom 
pavelsavara:fix-v8
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Pull request overview
This PR adjusts the browser/wasm JavaScript loader’s polyfill initialization to add an atob fallback for shell (V8/d8) scenarios used during engine feature detection, and updates various V8 invocation scripts/comments to stop passing --experimental-wasm-exnref.
Changes:
  • Split/rename polyfill initialization into “early” vs “loader” phases and add an atob polyfill for shell environments.
  • Remove --experimental-wasm-exnref from V8/Node invocation in wasm sample and generated run-v8 script.
  • Update pipeline comments referencing the Helix V8 limitation.
Reviewed changes
Copilot reviewed 9 out of 9 changed files in this pull request and generated 3 comments.
Show a summary per file
FileDescription
src/native/libs/Common/JavaScript/loader/run.tsRenames the loader polyfill entrypoint call to initPolyfillsLoader().
src/native/libs/Common/JavaScript/loader/polyfills.tsAdds shell atob polyfill and renames polyfill init functions.
src/native/libs/Common/JavaScript/loader/dotnet.tsSwitches early polyfill initialization to initPolyfillsEarly().
src/mono/sample/wasm/wasm.mkRemoves --experimental-wasm-exnref from sample run commands.
src/mono/sample/wasm/console-v8/Wasm.Console.V8.Sample.csprojRemoves --experimental-wasm-exnref from the V8 XHarness run command.
src/mono/browser/build/BrowserWasmApp.targetsUpdates generated run-v8.sh to no longer pass --experimental-wasm-exnref.
eng/pipelines/runtime-linker-tests.ymlUpdates comment wording about Helix V8 “exnref” support.
eng/pipelines/performance/runtime-wasm-perf.ymlUpdates comment wording about V8 “exnref” support.
eng/pipelines/common/templates/wasm-runtime-tests.ymlUpdates comment wording about V8 “exnref” support.
Comment threadsrc/native/libs/Common/JavaScript/loader/polyfills.ts
Comment threadsrc/mono/browser/build/BrowserWasmApp.targets
Comment threadeng/pipelines/common/templates/wasm-runtime-tests.yml

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marked this pull request as ready for review
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Pull request overview
Copilot reviewed 10 out of 10 changed files in this pull request and generated 4 comments.
Comment threadsrc/native/libs/Common/JavaScript/loader/polyfills.ts
Comment threadsrc/native/libs/Common/JavaScript/loader/polyfills.ts
Comment threadsrc/mono/browser/build/BrowserWasmApp.targets
Comment threadsrc/mono/browser/runtime/loader/polyfills.ts
@lewing
Remove remaining --experimental-wasm-exnref flags
7dcfd66
exnref is no longer experimental in current V8 versions, so the flag
is unrecognized and produces warnings. Remove it from all remaining
runner templates, test execution targets, the Node sample, and docs.
Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com>

This was referenced Jul 6, 2026

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/ba-g unrelated failures
@pavelsavara
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merged commit 1b94594
into
dotnet:mainJul 10, 2026

203 of 210 checks passed

@pavelsavara
pavelsavara
deleted the

fix-v8

branch
July 10, 2026 16:12
@pavelsavarapavelsavara
mentioned this pull request
Jul 10, 2026
 Merged

@dotnet-maestrodotnet-maestroBot
mentioned this pull request
Jul 11, 2026
 Merged

lewing pushed a commit
that referenced
this pull request
Jul 11, 2026
@pavelsavara
[wasm] Bump helix V8 image and re-enable exnref CI legs (#129849) (#1…
508ea61
…30511)
Fixes#129849
## Background
The exnref migration (#129851) exposed CI failures on the WASM legs. #130142 fixed — `wasm-feature-detect`'s `exceptionsFinal()` used `atob`.
## Changes
**Bump the Linux Helix WebAssembly image to an exnref-capable V8**
- `ubuntu-26.04-helix-webassembly-amd64` → `@sha256:73db6e43…` (V8
**15.2.47**, verified locally by pulling the image and running `d8`).
Previous pin baked V8 15.0.243.
- Updated in `eng/pipelines/coreclr/templates/helix-queues-setup.yml`
and `eng/pipelines/libraries/helix-queues-setup.yml`.
- The Windows Helix digests and the azurelinux build container (V8
15.1.103) were already current, so they are unchanged.
**Re-enable the CI legs disabled against this issue**
- `eng/pipelines/common/templates/wasm-runtime-tests.yml` — removed
`sendToHelix: false` (Mono runtime tests run on Helix again).
- `eng/pipelines/runtime-linker-tests.yml` — removed
`SkipTrimmingTestsRun=true` (trimming tests execute on V8 again).
- `eng/pipelines/performance/runtime-wasm-perf.yml` — restored the
original `pr:` trigger (was `pr: none`).
- `eng/pipelines/runtime.yml` — re-enabled the CoreCLR `WasmTestOnV8`
smoke scenario.
**Harden the Chrome/V8 auto-updater**
- `src/tasks/WasmBuildTasks/UpdateChromeVersions.cs` — add a
minimum-version guard so a Chrome-milestone-derived V8 can no longer
silently downgrade the pinned `*_V8Version` below the exnref floor
(15.1.103), which had already reverted the pins once via the automated
bump. When the recomputed value would drop below the floor, the existing
version is kept (mirroring the existing CDN-unavailable fallback).
@dotnet-milestone-botdotnet-milestone-botBot
added this to the 11.0-preview7 milestone
Jul 11, 2026
eiriktsarpalis pushed a commit
that referenced
this pull request
Jul 15, 2026
@pavelsavara@lewing@eiriktsarpalis
[browser] atob polyfil for feature detection in V8 (#130142)
2916b42
Co-authored-by: Larry Ewing <lewing@gmail.com>
eiriktsarpalis pushed a commit
that referenced
this pull request
Jul 15, 2026
@pavelsavara@eiriktsarpalis
[wasm] Bump helix V8 image and re-enable exnref CI legs (#129849) (#1…
49a651a
…30511)
Fixes#129849
## Background
The exnref migration (#129851) exposed CI failures on the WASM legs. #130142 fixed — `wasm-feature-detect`'s `exceptionsFinal()` used `atob`.
## Changes
**Bump the Linux Helix WebAssembly image to an exnref-capable V8**
- `ubuntu-26.04-helix-webassembly-amd64` → `@sha256:73db6e43…` (V8
**15.2.47**, verified locally by pulling the image and running `d8`).
Previous pin baked V8 15.0.243.
- Updated in `eng/pipelines/coreclr/templates/helix-queues-setup.yml`
and `eng/pipelines/libraries/helix-queues-setup.yml`.
- The Windows Helix digests and the azurelinux build container (V8
15.1.103) were already current, so they are unchanged.
**Re-enable the CI legs disabled against this issue**
- `eng/pipelines/common/templates/wasm-runtime-tests.yml` — removed
`sendToHelix: false` (Mono runtime tests run on Helix again).
- `eng/pipelines/runtime-linker-tests.yml` — removed
`SkipTrimmingTestsRun=true` (trimming tests execute on V8 again).
- `eng/pipelines/performance/runtime-wasm-perf.yml` — restored the
original `pr:` trigger (was `pr: none`).
- `eng/pipelines/runtime.yml` — re-enabled the CoreCLR `WasmTestOnV8`
smoke scenario.
**Harden the Chrome/V8 auto-updater**
- `src/tasks/WasmBuildTasks/UpdateChromeVersions.cs` — add a
minimum-version guard so a Chrome-milestone-derived V8 can no longer
silently downgrade the pinned `*_V8Version` below the exnref floor
(15.1.103), which had already reverted the pins once via the automated
bump. When the recomputed value would drop below the floor, the existing
version is kept (mirroring the existing CDN-unavailable fallback).
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, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Universal Dark Mode - works on any site\n(function() {\n var enabled = true;\n \n function applyDarkMode() {\n if (!enabled) return;\n \n // Create style element if it doesn't exist\n var style = document.getElementById('universal-dark-mode-style');\n if (!style) {\n style = document.createElement('style');\n style.id = 'universal-dark-mode-style';\n document.head.appendChild(style);\n }\n \n // Dark mode CSS - inverts colors but preserves images/video\n style.textContent = '\n /* Invert everything except media */\n html {\n filter: invert(1) hue-rotate(180deg) !important;\n background: #1a1a2e !important;\n }\n \n /* Restore images, videos, iframes, canvas */\n img, video, iframe, canvas, svg, picture, [style*=\"background-image\"] {\n filter: invert(1) hue-rotate(180deg) !important;\n }\n \n /* Preserve specific elements that should not be inverted */\n .no-dark-mode, .no-dark-mode *,\n [data-theme=\"light\"], [data-theme=\"light\"],\n .ace_editor, .ace_editor *,\n .CodeMirror, .CodeMirror *,\n .monaco-editor, .monaco-editor *,\n .markdown-body pre, .markdown-body pre *,\n .highlight, .highlight *,\n pre code, pre code * {\n filter: none !important;\n }\n \n /* Fix common UI elements */\n .modal, .popup, .dropdown-menu, .tooltip, .popover {\n filter: invert(1) hue-rotate(180deg) !important;\n background: #2d2d44 !important;\n border-color: #444 !important;\n }\n \n /* Scrollbars */\n ::-webkit-scrollbar { background: #1a1a2e !important; }\n ::-webkit-scrollbar-thumb { background: #444 !important; }\n ::-webkit-scrollbar-thumb:hover { background: #555 !important; }\n \n /* Selection */\n ::selection { background: #4ecdc4 !important; color: #1a1a2e !important; }\n ::-moz-selection { background: #4ecdc4 !important; color: #1a1a2e !important; }\n ';\n }\n \n function removeDarkMode() {\n var style = document.getElementById('universal-dark-mode-style');\n if (style) style.remove();\n }\n \n // Toggle with Alt+Shift+D\n document.addEventListener('keydown', function(e) {\n if (e.altKey && e.shiftKey && e.key === 'D') {\n e.preventDefault();\n enabled = !enabled;\n if (enabled) {\n applyDarkMode();\n console.log('[Universal Dark Mode] Enabled');\n } else {\n removeDarkMode();\n console.log('[Universal Dark Mode] Disabled');\n }\n }\n });\n \n // Apply on load\n applyDarkMode();\n \n // Re-apply on dynamic content\n var observer = new MutationObserver(function(mutations) {\n if (enabled && !document.getElementById('universal-dark-mode-style')) {\n applyDarkMode();\n }\n });\n observer.observe(document.head, { childList: true });\n \n console.log('[Universal Dark Mode] Loaded - Press Alt+Shift+D to toggle');\n})();", "Universal Dark Mode");
}
} catch(__e) { console.warn('[Userscript:Universal Dark Mode]', __e); }
})();
})();

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[browser] atob polyfil for feature detection in V8 - #130142
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pavelsavara merged 4 commits into
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pavelsavara:fix-v8
Jul 10, 2026
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[browser] atob polyfil for feature detection in V8#130142
pavelsavara merged 4 commits into
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pavelsavara:fix-v8
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Pull request overview
This PR adjusts the browser/wasm JavaScript loader’s polyfill initialization to add an atob fallback for shell (V8/d8) scenarios used during engine feature detection, and updates various V8 invocation scripts/comments to stop passing --experimental-wasm-exnref.
Changes:
  • Split/rename polyfill initialization into “early” vs “loader” phases and add an atob polyfill for shell environments.
  • Remove --experimental-wasm-exnref from V8/Node invocation in wasm sample and generated run-v8 script.
  • Update pipeline comments referencing the Helix V8 limitation.
Reviewed changes
Copilot reviewed 9 out of 9 changed files in this pull request and generated 3 comments.
Show a summary per file
FileDescription
src/native/libs/Common/JavaScript/loader/run.tsRenames the loader polyfill entrypoint call to initPolyfillsLoader().
src/native/libs/Common/JavaScript/loader/polyfills.tsAdds shell atob polyfill and renames polyfill init functions.
src/native/libs/Common/JavaScript/loader/dotnet.tsSwitches early polyfill initialization to initPolyfillsEarly().
src/mono/sample/wasm/wasm.mkRemoves --experimental-wasm-exnref from sample run commands.
src/mono/sample/wasm/console-v8/Wasm.Console.V8.Sample.csprojRemoves --experimental-wasm-exnref from the V8 XHarness run command.
src/mono/browser/build/BrowserWasmApp.targetsUpdates generated run-v8.sh to no longer pass --experimental-wasm-exnref.
eng/pipelines/runtime-linker-tests.ymlUpdates comment wording about Helix V8 “exnref” support.
eng/pipelines/performance/runtime-wasm-perf.ymlUpdates comment wording about V8 “exnref” support.
eng/pipelines/common/templates/wasm-runtime-tests.ymlUpdates comment wording about V8 “exnref” support.
Comment threadsrc/native/libs/Common/JavaScript/loader/polyfills.ts
Comment threadsrc/mono/browser/build/BrowserWasmApp.targets
Comment threadeng/pipelines/common/templates/wasm-runtime-tests.yml

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/ba-g untracked failures are unrelated
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Pull request overview
Copilot reviewed 10 out of 10 changed files in this pull request and generated 4 comments.
Comment threadsrc/native/libs/Common/JavaScript/loader/polyfills.ts
Comment threadsrc/native/libs/Common/JavaScript/loader/polyfills.ts
Comment threadsrc/mono/browser/build/BrowserWasmApp.targets
Comment threadsrc/mono/browser/runtime/loader/polyfills.ts
@lewing
Remove remaining --experimental-wasm-exnref flags
7dcfd66
exnref is no longer experimental in current V8 versions, so the flag
is unrecognized and produces warnings. Remove it from all remaining
runner templates, test execution targets, the Node sample, and docs.
Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com>

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/ba-g unrelated failures
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merged commit 1b94594
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fix-v8

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lewing pushed a commit
that referenced
this pull request
Jul 11, 2026
@pavelsavara
[wasm] Bump helix V8 image and re-enable exnref CI legs (#129849) (#1…
508ea61
…30511)
Fixes#129849
## Background
The exnref migration (#129851) exposed CI failures on the WASM legs. #130142 fixed — `wasm-feature-detect`'s `exceptionsFinal()` used `atob`.
## Changes
**Bump the Linux Helix WebAssembly image to an exnref-capable V8**
- `ubuntu-26.04-helix-webassembly-amd64` → `@sha256:73db6e43…` (V8
**15.2.47**, verified locally by pulling the image and running `d8`).
Previous pin baked V8 15.0.243.
- Updated in `eng/pipelines/coreclr/templates/helix-queues-setup.yml`
and `eng/pipelines/libraries/helix-queues-setup.yml`.
- The Windows Helix digests and the azurelinux build container (V8
15.1.103) were already current, so they are unchanged.
**Re-enable the CI legs disabled against this issue**
- `eng/pipelines/common/templates/wasm-runtime-tests.yml` — removed
`sendToHelix: false` (Mono runtime tests run on Helix again).
- `eng/pipelines/runtime-linker-tests.yml` — removed
`SkipTrimmingTestsRun=true` (trimming tests execute on V8 again).
- `eng/pipelines/performance/runtime-wasm-perf.yml` — restored the
original `pr:` trigger (was `pr: none`).
- `eng/pipelines/runtime.yml` — re-enabled the CoreCLR `WasmTestOnV8`
smoke scenario.
**Harden the Chrome/V8 auto-updater**
- `src/tasks/WasmBuildTasks/UpdateChromeVersions.cs` — add a
minimum-version guard so a Chrome-milestone-derived V8 can no longer
silently downgrade the pinned `*_V8Version` below the exnref floor
(15.1.103), which had already reverted the pins once via the automated
bump. When the recomputed value would drop below the floor, the existing
version is kept (mirroring the existing CDN-unavailable fallback).
@dotnet-milestone-botdotnet-milestone-botBot
added this to the 11.0-preview7 milestone
Jul 11, 2026
eiriktsarpalis pushed a commit
that referenced
this pull request
Jul 15, 2026
@pavelsavara@lewing@eiriktsarpalis
[browser] atob polyfil for feature detection in V8 (#130142)
2916b42
Co-authored-by: Larry Ewing <lewing@gmail.com>
eiriktsarpalis pushed a commit
that referenced
this pull request
Jul 15, 2026
@pavelsavara@eiriktsarpalis
[wasm] Bump helix V8 image and re-enable exnref CI legs (#129849) (#1…
49a651a
…30511)
Fixes#129849
## Background
The exnref migration (#129851) exposed CI failures on the WASM legs. #130142 fixed — `wasm-feature-detect`'s `exceptionsFinal()` used `atob`.
## Changes
**Bump the Linux Helix WebAssembly image to an exnref-capable V8**
- `ubuntu-26.04-helix-webassembly-amd64` → `@sha256:73db6e43…` (V8
**15.2.47**, verified locally by pulling the image and running `d8`).
Previous pin baked V8 15.0.243.
- Updated in `eng/pipelines/coreclr/templates/helix-queues-setup.yml`
and `eng/pipelines/libraries/helix-queues-setup.yml`.
- The Windows Helix digests and the azurelinux build container (V8
15.1.103) were already current, so they are unchanged.
**Re-enable the CI legs disabled against this issue**
- `eng/pipelines/common/templates/wasm-runtime-tests.yml` — removed
`sendToHelix: false` (Mono runtime tests run on Helix again).
- `eng/pipelines/runtime-linker-tests.yml` — removed
`SkipTrimmingTestsRun=true` (trimming tests execute on V8 again).
- `eng/pipelines/performance/runtime-wasm-perf.yml` — restored the
original `pr:` trigger (was `pr: none`).
- `eng/pipelines/runtime.yml` — re-enabled the CoreCLR `WasmTestOnV8`
smoke scenario.
**Harden the Chrome/V8 auto-updater**
- `src/tasks/WasmBuildTasks/UpdateChromeVersions.cs` — add a
minimum-version guard so a Chrome-milestone-derived V8 can no longer
silently downgrade the pinned `*_V8Version` below the exnref floor
(15.1.103), which had already reverted the pins once via the automated
bump. When the recomputed value would drop below the floor, the existing
version is kept (mirroring the existing CDN-unavailable fallback).
@github-actionsgithub-actionsBot
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Aug 11, 2026
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Copilot left review comments
@lewinglewinglewing approved these changes
@javiercnjaviercnjaviercn approved these changes
@akoeplingerakoeplingerAwaiting requested review from akoeplingerakoeplinger is a code owner
@marafmarafAwaiting requested review from marafmaraf is a code owner

Assignees

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arch-wasmWebAssembly architecturearea-Hostos-browserBrowser variant of arch-wasm

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Milestone

11.0-preview7

Development

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4 participants

@pavelsavara@lewing@javiercn