The UMA and use count is recorded in the following code: https://source.chromium.org/chromium/chromium/src/+/main:content/browser/service_worker/service_worker_main_resource_loader_interceptor.cc;l=132;drc=a5bdf0106da2489011a9846f280f29872258a8dd
The usecount is set if the request URL is blob, and the navigation handle has the service worker client and the client has a controller. As you can see, we record UMA just before the usecount, which records the number of the blob URL and non-blob URL cases. Since we can see non negligible IsBlob true cases, I assumed that the usecount is broken. Note that it just says that SharedWorker is created under a page controlled by a ServiceWorker. We are not sure if the change brings a visible difference to the SharedWorker. Considering what I have mentioned before, I should have added the metrics like: - clients.matchAll() or match() look up the SharedWorker where the SharedWorker script is a blob URL. - SharedWorker fetches other resources while the SharedWorker script is a blob URL. They should be the case affected by this change. Is there anything else I missed? 2025年3月11日(火) 4:38 Chris Harrelson <chris...@chromium.org>: > Were you able to manually > verify the SharedWorkerScriptUnderServiceWorkerControlIsBlob use counter > hits with a test page? If so, I suppose it's possible no one is using this > combination of features? Do you know of any site at all that does so? > > On Wed, Mar 5, 2025 at 5:32 PM 'Yoshisato Yanagisawa' via blink-dev < > blink-dev@chromium.org> wrote: > >> Sorry for not working on this for a long time. >> Considering what I am seeing with other statistics, I am assuming the use >> count is wrong. >> Last Dec, I started to do analysis on >> https://chromestatus.com/metrics/feature/timeline/popularity/5, however >> it is really cumbersome to find a SharedWorker script in obfuscated >> JavaScript and the analysis did not go well. >> As far as I understand, SharedWorker behavior change may happen: >> 1. if SharedWorker `fetch()`, and the request is intercepted by the >> ServiceWorker. >> 2. or if the ServiceWorker tries to look up the SharedWorker as its >> client, and postMessage(). >> >> I did not follow the 1 case, but as far as I checked 50 sites from the >> beginning listed with >> https://chromestatus.com/metrics/feature/timeline/popularity/5, I could >> not find the case like 2. >> Therefore, I assume the risk is quite low. >> >> If the risk matters, I can also do the deprecation study. >> >> >> 2025年3月5日(水) 23:14 Daniel Bratell <bratel...@gmail.com>: >> >>> I assume it's this use counter: >>> https://chromestatus.com/metrics/feature/timeline/popularity/5203 >>> (SharedWorkerScriptUnderServiceWorkerControlIsBlob). It doesn't seem to >>> have picked up any usage, which is either good or bad... >>> >>> yyanagisawa, do you know which it is? >>> >>> /Daniel >>> On 2024-11-26 10:00, Domenic Denicola wrote: >>> >>> >>> >>> On Tue, Nov 26, 2024 at 4:20 PM Yoshisato Yanagisawa < >>> yyanagis...@google.com> wrote: >>> >>>> Thanks for the response, >>>> Let me reply inline. >>>> >>>> 2024年11月19日(火) 15:56 Domenic Denicola <dome...@chromium.org>: >>>> >>>>> >>>>> >>>>> On Tue, Nov 19, 2024 at 2:15 PM Yoshisato Yanagisawa < >>>>> yyanagis...@google.com> wrote: >>>>> >>>>>> >>>>>> >>>>>> 2024年11月18日(月) 17:02 Domenic Denicola <dome...@chromium.org>: >>>>>> >>>>>>> >>>>>>> >>>>>>> On Friday, November 15, 2024 at 9:14:09 AM UTC+9 Chromestatus wrote: >>>>>>> >>>>>>> Contact emails yyanagis...@google.com >>>>>>> >>>>>>> Explainer None >>>>>>> >>>>>>> Specification https://w3c.github.io/ServiceWorker/#control-and- >>>>>>> use-worker-client >>>>>>> >>>>>>> Summary >>>>>>> >>>>>>> According to https://w3c.github.io/ServiceWorker/#control-and- >>>>>>> use-worker-client, workers should inherit controllers for the blob >>>>>>> URL. However, existing code allows only dedicated workers to inherit the >>>>>>> controller, and shared workers do not inherit the controller. This is >>>>>>> the >>>>>>> fix to make Chromium behavior adjust to the specification. An enterprise >>>>>>> policy SharedWorkerBlobURLFixEnabled is available to control this >>>>>>> feature. >>>>>>> >>>>>>> >>>>>>> Blink component Blink>Workers >>>>>>> <https://bugs.chromium.org/p/chromium/issues/list?q=component:Blink%3EWorkers> >>>>>>> >>>>>>> TAG review None >>>>>>> >>>>>>> TAG review status Not applicable >>>>>>> >>>>>>> Risks >>>>>>> >>>>>>> >>>>>>> Interoperability and Compatibility >>>>>>> >>>>>>> This is a change to make the Chromium behavior aligned with the >>>>>>> specification, there should not be an interoperability issue. However, >>>>>>> there is a compatibility issue from the past Chromium. If a blob URL is >>>>>>> used for a SharedWorker script and a controller for the URL is mattered, >>>>>>> there is a behavior change because this change makes a controller >>>>>>> inherited. An enterprise policy was added to allow enterprise customers >>>>>>> to >>>>>>> preserve the past Chromium behavior. >>>>>>> >>>>>>> Do you have any metrics on how many page loads this change might >>>>>>> impact? An enterprise policy seems like a good idea, but if the number >>>>>>> of >>>>>>> page loads is high, we might want to consider a deprecation trial or >>>>>>> similar mechanism. >>>>>>> >>>>>>> >>>>>> >>>>>> Yes. The I2S was proposed as the web facing change PSA ( >>>>>> https://groups.google.com/a/chromium.org/g/blink-dev/c/hClP93e4MLk/m/SGXfxOZfAQAJ) >>>>>> before, and I gave up to go with the PSA due to the amount of the case >>>>>> that >>>>>> the blob URL is used as a SharedWorker script URL is too large. >>>>>> I revisited the metrics and saw 10-40% SharedWorker script URLs are >>>>>> blob URL depending on platform. >>>>>> Is it better to go with a deprecation trial? >>>>>> >>>>> >>>>> 10-40% is very high, so yes, we need to consider ways to find an upper >>>>> limit on the danger. >>>>> >>>>> My guess is that most pages will not have their behavior changed, >>>>> because, for example, their service worker JavaScript ignores non-https: >>>>> fetches. The fact that these pages probably work fine in Safari is also >>>>> helpful evidence. >>>>> >>>>> I would suggest two strategies: >>>>> >>>>> - Use UKM or HTTP Archive to examine the top-N sites that trigger >>>>> this UseCounter (maybe N = 20 or so is good). Confirm via code >>>>> inspection >>>>> or running with the flag flipped or similar techniques that there is no >>>>> compat impact. Publish this data for the API owners to see. >>>>> >>>>> >>>> Sure. >>>> https://chromium-review.googlesource.com/c/chromium/src/+/6049677 to >>>> add UKM and UseCounter. >>>> Let's see the statistics after it is shipped. >>>> >>> >>> Oh, my suggestion was to get data sooner, by using the existing use >>> counter with HTTP archive analysis >>> <https://www.chromium.org/blink/platform-predictability/compat-tools/>. >>> Then you don't have to wait for any code to roll out to stable. >>> >>>> >>>>> - Also do a deprecation trial to allow opting in to the old >>>>> behavior. The UKM/HTTP archive analysis can increase our confidence >>>>> that >>>>> the breakage is low (like, if 0 or 1 out of 20 pages are broken, then >>>>> the >>>>> breakage is probably <1%). But it cannot give us enough precision to be >>>>> confident, so having the escape hatch of the deprecation trial seems >>>>> important. >>>>> >>>>> Just let me confirm if my understanding is correct. >>>> Does the deprecation trial mean the origin trial to preserve the legacy >>>> behavior? >>>> We enable the flag by default while starting the origin trial. The >>>> site with the origin trial token can preserve the legacy behavior, right? >>>> >>> >>> Yes, that's the idea! See this link >>> <https://www.chromium.org/blink/launching-features/#deprecation-trial>. >>> I guess the wording there is a bit confusing since you aren't "removing" a >>> feature, but instead changing how an existing feature works. I think it >>> should not matter much though. It is still closer to a deprecation trial >>> than an origin trial. For example, you do not need to write a specification >>> for the behavior that the trial enables, like you would with an origin >>> trial. >>> >>> >>>> >>>> >>>>> I'm sorry that this adds so much process for what is basically a bug >>>>> fix. It is possible there would be other ways to avoid it, for example by >>>>> creating a more precise use counter that detects "changed behavior". (But, >>>>> it is hard to imagine how to write the code for such a use counter... >>>>> maybe >>>>> something about comparing response bytes??) However my guess is that the >>>>> time and effort of writing that precise use counter is probably more than >>>>> the effort in setting up a deprecation trial. So my advice is to pursue >>>>> the >>>>> above approach. >>>>> >>>>> >>>>>> >>>>>> >>>>>>> >>>>>>> >>>>>>> *Gecko*: No signal >>>>>>> >>>>>>> >>>>>>> Can you ask Gecko for signals? I am especially curious why they >>>>>>> haven't updated to match the specification. >>>>>>> >>>>>>> >>>>>> >>>>>> Sure. I have filed the mozilla's standard position for it. >>>>>> https://github.com/mozilla/standards-positions/issues/1113 >>>>>> >>>>>> >>>>>>> >>>>>>> >>>>>>> *WebKit*: Shipped/Shipping >>>>>>> >>>>>>> *Web developers*: No signals >>>>>>> >>>>>>> *Other signals*: >>>>>>> >>>>>>> Ergonomics >>>>>>> >>>>>>> n/a >>>>>>> >>>>>>> >>>>>>> Security >>>>>>> >>>>>>> Since this is adjusting Chromium behavior to specification, there >>>>>>> should not be a security risk from a specification perspective. From the >>>>>>> implementation perspective, this change simply inherits existing >>>>>>> controller. There should not be any additional security risks with this >>>>>>> change. >>>>>>> >>>>>>> >>>>>>> WebView application risks >>>>>>> >>>>>>> Does this intent deprecate or change behavior of existing APIs, such >>>>>>> that it has potentially high risk for Android WebView-based >>>>>>> applications? >>>>>>> >>>>>>> Since SharedWorker is not supported on Android yet, there is no risk >>>>>>> on Android WebView. >>>>>>> >>>>>>> >>>>>>> Debuggability >>>>>>> >>>>>>> n/a >>>>>>> >>>>>>> >>>>>>> Will this feature be supported on all six Blink platforms (Windows, >>>>>>> Mac, Linux, ChromeOS, Android, and Android WebView)? No >>>>>>> >>>>>>> Since SharedWorker is not supported in Android yet, the feature also >>>>>>> does not affect to Android. >>>>>>> >>>>>>> >>>>>>> Is this feature fully tested by web-platform-tests >>>>>>> <https://chromium.googlesource.com/chromium/src/+/main/docs/testing/web_platform_tests.md> >>>>>>> ? Yes >>>>>>> >>>>>>> https://wpt.fyi/results/service-workers/service- >>>>>>> worker/local-url-inherit-controller.https.html Same-origin blob URL >>>>>>> sharedworker should inherit service worker controller. Same-origin blob >>>>>>> URL >>>>>>> sharedworker should intercept fetch(). The tests ensure a >>>>>>> ServiceWorkerController is inherited. Due to crbug.com/40364838, >>>>>>> Chromium does not pass the former test. >>>>>>> >>>>>>> >>>>>>> Flag name on about://flags None >>>>>>> >>>>>>> Finch feature name SharedWorkerBlobURLFix >>>>>>> >>>>>>> Requires code in //chrome? False >>>>>>> >>>>>>> Tracking bug https://crbug.com/324939068 >>>>>>> >>>>>>> Estimated milestones Shipping on desktop 133 >>>>>>> >>>>>>> Anticipated spec changes >>>>>>> >>>>>>> Open questions about a feature may be a source of future web compat >>>>>>> or interop issues. Please list open issues (e.g. links to known github >>>>>>> issues in the project for the feature specification) whose resolution >>>>>>> may >>>>>>> introduce web compat/interop risk (e.g., changing to naming or >>>>>>> structure of >>>>>>> the API in a non-backward-compatible way). >>>>>>> None >>>>>>> >>>>>>> Link to entry on the Chrome Platform Status >>>>>>> https://chromestatus.com/feature/5137897664806912?gate= >>>>>>> 5147843735322624 >>>>>>> >>>>>>> This intent message was generated by Chrome Platform Status >>>>>>> <https://chromestatus.com>. >>>>>>> >>>>>>> -- >>> You received this message because you are subscribed to the Google >>> Groups "blink-dev" group. >>> To unsubscribe from this group and stop receiving emails from it, send >>> an email to blink-dev+unsubscr...@chromium.org. >>> To view this discussion visit >>> https://groups.google.com/a/chromium.org/d/msgid/blink-dev/CAM0wra9fn%2B7i8%3DOh72j43C7nVeG4%3D850zaqZShgiaAhhTVBCpA%40mail.gmail.com >>> <https://groups.google.com/a/chromium.org/d/msgid/blink-dev/CAM0wra9fn%2B7i8%3DOh72j43C7nVeG4%3D850zaqZShgiaAhhTVBCpA%40mail.gmail.com?utm_medium=email&utm_source=footer> >>> . >>> >>> -- >> You received this message because you are subscribed to the Google Groups >> "blink-dev" group. >> To unsubscribe from this group and stop receiving emails from it, send an >> email to blink-dev+unsubscr...@chromium.org. >> To view this discussion visit >> https://groups.google.com/a/chromium.org/d/msgid/blink-dev/CAPNB-6XY_%3DTj%3DWyi%3Dhh%3D-wny5beHqNAT7G_ObTR4eof-duXNdQ%40mail.gmail.com >> <https://groups.google.com/a/chromium.org/d/msgid/blink-dev/CAPNB-6XY_%3DTj%3DWyi%3Dhh%3D-wny5beHqNAT7G_ObTR4eof-duXNdQ%40mail.gmail.com?utm_medium=email&utm_source=footer> >> . >> > -- You received this message because you are subscribed to the Google Groups "blink-dev" group. 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