A GitHub project page with embedded SVG takes an extremely long time to load

Bug 262192 - A GitHub project page with embedded SVG takes an extremely long time to load

Website: https://github.com/facebookincubator/below

The website takes a long time to load, the page hangs. Navigating to sub-links is also slow. This is a WebKit specific behavior, the website loads fine on Chrome. I also tried disabling all the extensions but this looks like a bug with WebKit.

Thsnk you for the report! As this is reported against Safari 17, do you happen to know if this was happening with Safari 16.x before?

It's taking time under LegacyRenderSVGRoot::layout -> SVGTextMetricsBuilder::walkTree -> WebCore::Font::applyTransforms.

Thanks for the prompt response. Yes, this was happening in Safari 16.x as well.
I had reported this for Safari 16 using Feedback Assistant but I should have known better.

Lots of time under:
     2404 WebCore::RenderBlockFlow::layoutBlockChildren(bool, WebCore::LayoutUnit&)  (in WebCore) + 4960  [0x61767b2b0]
       2404 WebCore::LegacyRenderSVGRoot::layout()  (in WebCore) + 1094  [0x6178bfe86]
         2404 WebCore::SVGRenderSupport::layoutChildren(WebCore::RenderElement&, bool)  (in WebCore) + 706  [0x6178a03d2]
           2404 WebCore::LegacyRenderSVGContainer::layout()  (in WebCore) + 269  [0x6178b5a6d]
             2404 WebCore::SVGRenderSupport::layoutChildren(WebCore::RenderElement&, bool)  (in WebCore) + 706  [0x6178a03d2]
               2402 WebCore::RenderSVGText::layout()  (in WebCore) + 1309  [0x61558439d]
               ! 2398 WebCore::SVGTextMetricsBuilder::walkTree(WebCore::RenderElement&, WebCore::RenderSVGInlineText*, WebCore::MeasureTextData*)  (in WebCore) + 127  [0x6178b3b4f]
               ! : 2329 WebCore::SVGTextMetricsBuilder::walkTree(WebCore::RenderElement&, WebCore::RenderSVGInlineText*, WebCore::MeasureTextData*)  (in WebCore) + 127  [0x6178b3b4f]
               ! : | 2279 WebCore::SVGTextMetricsBuilder::walkTree(WebCore::RenderElement&, WebCore::RenderSVGInlineText*, WebCore::MeasureTextData*)  (in WebCore) + 92  [0x6178b3b2c]
               ! : | + 1997 WebCore::SVGTextMetricsBuilder::measureTextRenderer(WebCore::RenderSVGInlineText&, WebCore::MeasureTextData*)  (in WebCore) + 1358  [0x6178b31ce]
               ! : | + ! 1404 WebCore::WidthIterator::advance(unsigned int, WebCore::GlyphBuffer&)  (in WebCore) + 188  [0x6174737cc]
               ! : | + ! : 1098 WebCore::WidthIterator::advanceInternal<WebCore::Latin1TextIterator>(WebCore::Latin1TextIterator&, WebCore::GlyphBuffer&)  (in WebCore) + 4011  [0x617474c7b]
               ! : | + ! : | 1054 WebCore::WidthIterator::commitCurrentFontRange(WebCore::AdvanceInternalState&)  (in WebCore) + 963  [0x6174722d3]

<rdar://problem/116188712>

One potential merge: https://src.chromium.org/viewvc/blink?view=revision&revision=168005

> Eliminate recursion in SVGTextMetricsBuilder::walkTree

I think it is fixed on WebKit ToT (270133@main).

Is there a way to verify this, maybe in Safari TP? I am not sure which commit fixed it, so cannot check in release notes.

(In reply to cueball045 from comment #7)
> Is there a way to verify this, maybe in Safari TP? I am not sure which
> commit fixed it, so cannot check in release notes.

I think it might be fixed because of following commit:

https://commits.webkit.org/270110@main

Which is not in Safari Technology Preview. It might be in STP183 or STP184 or even STP185.

That's super helpful. Thanks a lot!

Yeah, this appears to be fixed on trunk.