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.
