Open
Bug 1407401
Opened 7 years ago
Updated 7 months ago
Hard refresh causing severe flash of unstyled content
Categories
(Core :: Layout, defect, P3)
Core
Layout
Tracking
()
NEW
Tracking | Status | |
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firefox57 | --- | wontfix |
People
(Reporter: jhirsch, Unassigned)
References
Details
Attachments
(2 files)
Noticed in recent Nightlies (started 10/6, still affects 10/10) that Github pull request pages cause a really long FOUC when the page is hard refreshed, but not on initial page load. Here's an example page: https://github.com/mozilla-services/screenshots/pull/3614 I also see the FOUC when I first switch to a tab after a restart, which I suspect is just another way to hard refresh a page. The only error I see in the browser toolbox is a CSP error: "Ignoring ‘x-frame-options’ because of ‘frame-ancestors’ directive". Not sure why this would affect refreshes, but not initial loads. I'll attach a screen capture video of loading, then hard refreshing.
Reporter | ||
Comment 1•7 years ago
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On 9/26 and 9/15 nightlies, I see the FOUC on initial load, as well as on refresh. No FOUC on initial load on today's nightly.
Comment 2•7 years ago
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Could you try to get a regression range using mozregression? (See http://mozilla.github.io/mozregression/documentation/ for instruction)
Updated•7 years ago
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Flags: needinfo?(jhirsch)
Reporter | ||
Comment 3•7 years ago
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Yup, mozregression results: 18:41.15 INFO: Last good revision: 8d3fcb61cc736bc8269a926ab3265fa9b0d9b8e5 18:41.15 INFO: First bad revision: c15a167e6e89787a047686d03b32f7d27947936d 18:41.15 INFO: Pushlog: https://hg.mozilla.org/integration/mozilla-inbound/pushloghtml?fromchange=8d3fcb61cc736bc8269a926ab3265fa9b0d9b8e5&tochange=c15a167e6e89787a047686d03b32f7d27947936d
Flags: needinfo?(jhirsch)
Comment 4•7 years ago
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I think this is somewhat an intentional effect of that patch, and I recall seeing something related to that and FOUC, but I'd rather let Ehsan confirm.
Flags: needinfo?(ehsan)
Reporter | ||
Comment 5•7 years ago
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It looks like any issue page or pull request page on github.com triggers this FOUC problem. Looking at the performance in devtools, I can see why the FOUC might be happening. It looks like the page minimum render speed is around 2.8 fps. At those times, I see things like: - a block of order of 100s of style recalculations - followed by order of 10s of re-layouts - followed by order of 100s of promise callbacks - then back to tens/hundreds of style recalculations, etc I saved the performance data, and the JSON file is attached.
Reporter | ||
Comment 6•7 years ago
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I think the mozregression window doesn't tell the whole story. In the older nightlies, I noticed that the FOUC happens on initial page load. In newer nightlies, FOUC doesn't happen on initial load; it only occurs when the page is hard refreshed. I'll do another mozregression to figure out when this changed.
Reporter | ||
Comment 7•7 years ago
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> In newer nightlies, FOUC doesn't happen on initial load; it only occurs when the page is hard refreshed. Ah, nope. In latest nightly, the URL in comment 0 shows a really ugly FOUC when it's first loaded into a new tab, and on refresh also.
Comment 8•7 years ago
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(In reply to Emilio Cobos Álvarez [:emilio] from comment #4) > I think this is somewhat an intentional effect of that patch, and I recall > seeing something related to that and FOUC, but I'd rather let Ehsan confirm. No, it isn't, but comment 6 seems to suggest FOUC is unrelated to that patch.
Comment 9•7 years ago
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Breaking here should tell you why the FOUC is happening: <https://searchfox.org/mozilla-central/rev/31606bbabc50b08895d843b9f5f3da938ccdfbbf/dom/base/nsContentSink.cpp#1260>
Flags: needinfo?(ehsan)
Comment 10•7 years ago
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Err, right. I remember this being investigated on https://groups.google.com/d/msg/mozilla.dev.platform/uN4idW92CCQ/KKnYiOkOAwAJ.
Updated•7 years ago
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status-firefox57:
--- → wontfix
Priority: -- → P3
Comment 11•6 years ago
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Dup of bug 1404468?
Updated•2 years ago
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Severity: normal → S3
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Description
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