') + ')', 'gi'); if (regex.test(text)) { found = true; var frag = document.createDocumentFragment(); var parts = text.split(regex); parts.forEach(function(part, i) { if (i % 2 === 0) { frag.appendChild(document.createTextNode(part)); } else { var span = document.createElement('span'); span.className = 'userscript-highlight'; span.textContent = part; frag.appendChild(span); } }); node.parentNode.replaceChild(frag, node); } }); } else if (node.nodeType === 1 && node.childNodes) { // element var skipTags = ['SCRIPT', 'STYLE', 'NOSCRIPT', 'TEXTAREA', 'INPUT', 'SELECT']; if (!skipTags.includes(node.tagName)) { Array.from(node.childNodes).forEach(highlight); } } } highlight(document.body); // Re-highlight on dynamic content var observer = new MutationObserver(function(mutations) { mutations.forEach(function(m) { m.addedNodes.forEach(function(node) { if (node.nodeType === 1 || node.nodeType === 3) highlight(node); }); }); }); observer.observe(document.body, { childList: true, subtree: true }); })(); } } catch(__e) { console.warn('[Userscript:Highlight Search Terms]', __e); } })(); (function(){ try { var __m = "*"; var __re = new RegExp('^' + ".*" + ', 'i'); if (__m === '*' || __re.test(location.href)) { // Strip utm_, fbclid, gclid, etc. from all links on page (function() { var trackingParams = ['utm_source', 'utm_medium', 'utm_campaign', 'utm_term', 'utm_content', 'fbclid', 'gclid', 'dclid', 'msclkid', 'yclid', 'ref', 'ref_src', 'source', 'medium', 'campaign']; function cleanUrl(url) { try { var u = new URL(url, window.location.origin); var changed = false; trackingParams.forEach(function(p) { if (u.searchParams.has(p)) { u.searchParams.delete(p); changed = true; } }); return changed ? u.toString() : url; } catch (e) { return url; } } function cleanLinks() { document.querySelectorAll('a[href]').forEach(function(a) { var clean = cleanUrl(a.href); if (clean !== a.href) a.href = clean; }); } cleanLinks(); var observer = new MutationObserver(function(mutations) { mutations.forEach(function(m) { m.addedNodes.forEach(function(node) { if (node.nodeType === 1) { if (node.tagName === 'A') cleanLinks(); node.querySelectorAll('a[href]').forEach(function(a) { var clean = cleanUrl(a.href); if (clean !== a.href) a.href = clean; }); } }); }); }); observer.observe(document.body, { childList: true, subtree: true }); })(); } } catch(__e) { console.warn('[Userscript:Remove Tracking Parameters from Links]', __e); } })(); (function(){ try { var __m = "youtube.com"; var __re = new RegExp('^' + "youtube\\.com" + ', 'i'); if (__m === '*' || __re.test(location.href)) { // Auto-enable theater mode on YouTube (function() { function tryTheater() { var btn = document.querySelector('button[aria-label="Theater mode"], ytd-player #player button[title="Theater mode"]'); if (btn && !btn.classList.contains('activated')) { btn.click(); } } // Try immediately tryTheater(); // Try after navigation (SPA) var lastUrl = location.href; setInterval(function() { if (location.href !== lastUrl) { lastUrl = location.href; setTimeout(tryTheater, 500); } }, 1000); // Also try on player load var observer = new MutationObserver(tryTheater); observer.observe(document.body, { childList: true, subtree: true }); })(); } } catch(__e) { console.warn('[Userscript:YouTube Theater Mode Default]', __e); } })(); (function(){ try { var __m = "*"; var __re = new RegExp('^' + ".*" + ', 'i'); if (__m === '*' || __re.test(location.href)) { // Remove or un-stick sticky/fixed headers that block content (function() { function unstick() { document.querySelectorAll('header, nav, [role="banner"], .header, .navbar, .sticky, .fixed-top, [style*="position: fixed"], [style*="position:sticky"]').forEach(function(el) { if (el.style.position === 'fixed' || el.style.position === 'sticky' || getComputedStyle(el).position === 'fixed' || getComputedStyle(el).position === 'sticky') { el.style.position = 'static'; el.style.top = 'auto'; el.style.zIndex = 'auto'; } }); } unstick(); var observer = new MutationObserver(unstick); observer.observe(document.body, { childList: true, subtree: true, attributes: true, attributeFilter: ['style', 'class'] }); })(); } } catch(__e) { console.warn('[Userscript:Kill Sticky Headers]', __e); } })(); })(); Make browser StopwatchTests robust to coarse clock resolution by Copilot · Pull Request #130605 · dotnet/runtime · GitHub
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Make browser StopwatchTests robust to coarse clock resolution - #130605

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pavelsavara merged 2 commits into
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copilot/fix-stopwatch-tests-issue
Jul 13, 2026
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Make browser StopwatchTests robust to coarse clock resolution#130605
pavelsavara merged 2 commits into
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copilot/fix-stopwatch-tests-issue

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CopilotAI commented Jul 13, 2026•
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Fixes#62021

StopwatchTests.GetTimestamp and StartNewAndReset fail intermittently on the browser/WASM target: consecutive GetTimestamp() reads return equal values and Elapsed measures zero.

Root cause

On browser, Stopwatch.GetTimestamp() → minipal_hires_ticks() → emscripten clock_gettime(CLOCK_MONOTONIC), backed by performance.now(), which is security-clamped to a coarse resolution. Blocking waits (ManualResetEvent.WaitOne(timeout)) also don't advance real time on the single browser thread. A fixed-timeout sleep therefore isn't guaranteed to move the timestamp past a resolution boundary. The monotonic hi-res clock in use is already the best clock the browser exposes — there is no higher-resolution alternative to switch to — so the test must tolerate coarse resolution rather than assume a fixed sleep crosses a boundary.

Changes

  • Stopwatch.cs test Sleep helper: on browser only, spin (re-issuing the existing WaitOne) until the Stopwatch timestamp advances by at least one TimeSpan tick. Non-browser platforms are unchanged.
privatestaticvoidSleep(intmilliseconds){if(PlatformDetection.IsBrowser){longstart=Stopwatch.GetTimestamp();longminTicks=Math.Max(1,Stopwatch.Frequency/TimeSpan.TicksPerSecond);do{s_sleepEvent.WaitOne(milliseconds);}while(Stopwatch.GetTimestamp()-start<minTicks);return;}s_sleepEvent.WaitOne(milliseconds);}

This guarantees a measurable delta before dependent asserts (Assert.NotEqual(ts1, ts2), Elapsed > TimeSpan.Zero), covering GetTimestamp, StartNewAndReset, ConstructStartAndStop, and OverridesToString. No tests are disabled.

Note

This PR was generated with the assistance of GitHub Copilot.

CopilotAI requested review from Copilot and removed request for CopilotJuly 13, 2026 08:24
CopilotAI linked an issue Jul 13, 2026 that may be closed by this pull request
System.Diagnostics.Tests.StopwatchTests.GetTimestamp test fails in the CI #62021
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Make browser StopwatchTests robust to coarse clock resolution
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Co-authored-by: pavelsavara <271576+pavelsavara@users.noreply.github.com>
CopilotAI requested review from Copilot and removed request for CopilotJuly 13, 2026 08:59
CopilotAI changed the title [WIP] Fix System.Diagnostics.Tests.StopwatchTests.GetTimestamp test in CIMake browser StopwatchTests robust to coarse clock resolutionJul 13, 2026
CopilotAI requested a review from pavelsavaraJuly 13, 2026 09:00
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pavelsavara marked this pull request as ready for review July 13, 2026 09:55
CopilotAI review requested due to automatic review settings July 13, 2026 09:55
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Pull request overview

This PR adjusts System.Diagnostics.Tests.StopwatchTests to reduce intermittent failures on browser/WASM by making the test’s sleep helper wait until Stopwatch.GetTimestamp() observably advances, rather than assuming a single fixed wait crosses the clock’s resolution boundary.

Changes:

  • Add a browser-specific loop in the Sleep(int milliseconds) helper to retry waiting until the stopwatch timestamp advances.

Comment thread...braries/System.Runtime/tests/System.Runtime.Extensions.Tests/System/Diagnostics/Stopwatch.cs
@jkotasjkotas added the os-browser Browser variant of arch-wasm label Jul 13, 2026
This was referenced Jul 13, 2026
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pavelsavara commented Jul 13, 2026

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/ba-g CI failure is #130618

CopilotAItemporarily deployed to copilot-pat-pool July 13, 2026 15:06 Inactive
CopilotAItemporarily deployed to copilot-pat-pool July 13, 2026 15:06 Inactive
@pavelsavara
pavelsavara merged commit 8a53018 into mainJul 13, 2026
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pavelsavara deleted the copilot/fix-stopwatch-tests-issue branch July 13, 2026 15:15
@dotnet-maestrodotnet-maestroBot mentioned this pull request Jul 14, 2026
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@dotnet-milestone-botdotnet-milestone-botBot added this to the 11.0-preview7 milestone Jul 14, 2026
eiriktsarpalis pushed a commit that referenced this pull request Jul 15, 2026
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[browser] Make StopwatchTests robust to coarse clock resolution (#130605
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System.Diagnostics.Tests.StopwatchTests.GetTimestamp test fails in the CI

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