RESOLVED DUPLICATE of bug 299211300096
REGRESSION (Event Timing): Slack workspaces are blank 
https://bugs.webkit.org/show_bug.cgi?id=300096
Summary REGRESSION (Event Timing): Slack workspaces are blank
Jeff Johnson
Reported 2025-10-03 05:02:29 PDT
Created attachment 476949 [details] Screenshot of WebKit Slack workspace in STP 229 Safari Technology Preview 229 on macOS 15.7.1. This bug did not exist in Safari Technology Preview 228. All Slack workspaces are blank in Safari Technology Preview 299. This affects the WebKit Slack https://app.slack.com/client/T06G50708/ for example, as well as my own private Slack. Attached is a screenshot. The settings page https://webkit.slack.com/home still works fine.
Attachments
Screenshot of WebKit Slack workspace in STP 229 (118.07 KB, image/jpeg)
2025-10-03 05:02 PDT, Jeff Johnson 		no flags
Details
View All Add attachment proposed patch, testcase, etc.
Alexey Proskuryakov
Comment 1 2025-10-03 08:17:08 PDT
Thank you for the report! I can reproduce, and disabling Event Timing preview feature works around this. Unhandled Promise Rejection: TypeError: this.eventCounts.entries is not a function. (In 'this.eventCounts.entries()', 'this.eventCounts.entries' is undefined)
Radar WebKit Bug Importer
Comment 2 2025-10-03 08:18:12 PDT
<rdar://problem/161897012>
Jeff Johnson
Comment 3 2025-10-03 08:19:41 PDT
(In reply to Alexey Proskuryakov from comment #1) > Thank you for the report! I can reproduce, and disabling Event Timing > preview feature works around this. Confirmed, this workaround solves the problem, thanks!
Jeff Johnson
Comment 4 2025-10-03 09:53:29 PDT
It appears that the feature flag reenables itself on quit and relaunch of Safari Technology Preview. Is this a bug or expected behavior, and is there any way to permanently disable the flag?
Franco Vieira de Souza
Comment 5 2025-10-03 15:57:04 PDT
The root problem was solved on https://github.com/WebKit/WebKit/pull/51040 (https://bugs.webkit.org/show_bug.cgi?id=299211).
Alexey Proskuryakov
Comment 6 2025-10-04 19:10:31 PDT
So this should be duped to bug 299211 then? > Is this a bug or expected behavior, and is there any way to permanently disable the flag? I'll ask.
Franco Vieira de Souza
Comment 7 2025-10-04 19:19:03 PDT
*** This bug has been marked as a duplicate of bug 299211 ***
Jeff Johnson
Comment 8 2025-10-15 18:01:50 PDT
(In reply to Alexey Proskuryakov from comment #6) > > Is this a bug or expected behavior, and is there any way to permanently disable the flag? > > I'll ask. Any word on this?
Ryan Reno
Comment 9 2025-10-15 19:48:36 PDT
I do not know for sure about permanently disabling or enabling preview flags but the fix for this particular bug shipped today in Safari Technology Preview 230.
Alexey Proskuryakov
Comment 10 2025-10-16 14:33:03 PDT
> Is this a bug or expected behavior, and is there any way to permanently disable the flag? The answer is that "preview" features get re-enabled on each launch by design.
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