Bug 308175 – REGRESSION (303091@main): getClientRects() can include rects with no width and height

• Status: RESOLVED
• Resolution: FIXED
• Component: Layout and Rendering

[Brad Andalman]

Created attachment 478401 [details]
HTML that exhibits the bug

We make use of a slightly complicated method to "float" a text box. Sometimes this floating text box can affect a paragraph that splits across two columns in a multi-column view. When that happens, Safari Technology Preview 237 has different behavior than the released version of Safari. 

In order to inspect the position of the lines in each paragraph, we use a <span> element to contain the paragraph text. Then, we can call getClientRects() on that containing span. Prior to STP 237, each returned rect would represent a line in the paragraph (this is very useful, and is also how Chrome and Firefox behave).

With STP 237, getClientRects() can include a rect with a width and height of 0. This seems broken, even though it doesn't seem to affect the text layout in my test.

I'm attaching HTML that illustrates this problem. It contains JS so that, if it finds a rect with a width and height of 0, it will add a background color of "pink" to some text. Otherwise, the background for that text will be green.

[Brad Andalman]

Created attachment 478402 [details]
Screenshot showing the bug in STP 237 (and not in the released version of Safari)

[Radar WebKit Bug Importer]

<rdar://problem/170681795>

[Karl Dubost]

Created attachment 478406 [details]
rendering in safari, firefox, chrome

Thanks for the bug report and the testcase !


Rendering in 

Safari Technology Preview  236          21625.1.1.19.1
Firefox Nightly            149.0a1       14926.2.4
Google Chrome Canary       147.0.7694.0  7694.0

[Karl Dubost]

<span id="lorem-span">…</span> has a unknown size. not even displayed as 0x0 in the Web inspector.

[alan]

(In reply to Karl Dubost from comment #4)
> <span id="lorem-span">…</span> has a unknown size. not even displayed as 0x0
> in the Web inspector.

Such inline boxes do not normally show their size as they are prone to fragmentation e.g <span>first line <br>second line</span>

[alan]

Created attachment 478409 [details]
Patch

[alan]

Created attachment 478410 [details]
[fast-cq]Patch

[EWS]

Committed 307916@main (d02501613445): <https://commits.webkit.org/307916@main>

All reviewed patches have been landed. Closing bug and clearing flags on attachment 478410 [details].

[EWS]

Committed 305413.375@safari-7624-branch (da629230e759): <https://commits.webkit.org/305413.375@safari-7624-branch>

Reviewed commits have been landed. Closing PR #4572 and removing active labels.