fix(trace-viewer): remove speculative 1s isUnderTest startup delay - #42071
Open
Skn0tt wants to merge 2 commits into
Open
fix(trace-viewer): remove speculative 1s isUnderTest startup delay#42071Skn0tt wants to merge 2 commits into
Skn0tt wants to merge 2 commits into
Conversation
The delay was added in 2022 (microsoft#15330 / microsoft#15342) as a speculative flake fix while service-worker registration was being introduced, then copied into UI Mode. It only runs under test, so every Trace Viewer / UI Mode test paid ~1s on first interaction for no clear remaining reason. Local TV + UI mode suites pass without it; opening as draft so CI can soak any flake return. Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com> Copilot-Session: 30f3e9be-1f15-4e5c-9972-5f0253070639
This comment has been minimized.
This comment has been minimized.
This comment has been minimized.
This comment has been minimized.
Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com> Copilot-Session: 30f3e9be-1f15-4e5c-9972-5f0253070639
Member
Author
|
The one "should indicate current test status" flaky test looks related, but actually also flakes on other PRs, so it seems this is safe. I kicked off another CI run just to double-check. |
Contributor
Test results for "tests 1"7 flaky51112 passed, 1188 skipped Merge workflow run. |
Contributor
Test results for "MCP"2 failed 7261 passed, 1173 skipped Merge workflow run. |
Skn0tt
marked this pull request as ready for review
July 31, 2026 15:38
Contributor
🟢 CI is clear — both failures are pre-existing flakesHi, I'm the Playwright bot and I took a look at the failing CI on this PR. The two real failures are both in the MCP suite on the Windows bots, and both are the same tests that flake regularly on unrelated SHAs and PRs. This PR only removes a 1s startup delay in the Trace Viewer / UI Mode web frontends ( DetailsPre-existing flake / infra
Not triaged (flaky, passed on retry)
Triaged by the Playwright bot - agent run |
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
1 participant
Add this suggestion to a batch that can be applied as a single commit.This suggestion is invalid because no changes were made to the code.Suggestions cannot be applied while the pull request is closed.Suggestions cannot be applied while viewing a subset of changes.Only one suggestion per line can be applied in a batch.Add this suggestion to a batch that can be applied as a single commit.Applying suggestions on deleted lines is not supported.You must change the existing code in this line in order to create a valid suggestion.Outdated suggestions cannot be applied.This suggestion has been applied or marked resolved.Suggestions cannot be applied from pending reviews.Suggestions cannot be applied on multi-line comments.Suggestions cannot be applied while the pull request is queued to merge.Suggestion cannot be applied right now. Please check back later.
Removes the 1s
isUnderTestsleep before service-worker registration in Trace Viewer and UI Mode.It was added in 2022 as a speculative flake fix while SW registration was landing (#15330, then #15342), and later copied into UI Mode. It only runs under test, so every TV / UI Mode test was paying ~1s on first interaction. Looking at the history, there isn't a clear remaining reason for it.
Locally, full Trace Viewer and UI Mode suites pass without the delay. Opening as draft so CI can soak whether any of the original flakeiness comes back.