Bug 216160

Summary:	REGRESSION(r266509): [ iOS wk2 ] css2.1/t0905-c5525-fltwidth-00-c-g.html is a constant failure
Product:	WebKit	Reporter:	Hector Lopez <hector_i_lopez>
Component:	New Bugs	Assignee:	Nobody <webkit-unassigned>
Status:	NEW ---
Severity:	Normal	CC:	aakash_jain, ryanhaddad, webkit-bot-watchers-bugzilla, webkit-bug-importer, zalan
Priority:	P2	Keywords:	InRadar
Version:	WebKit Nightly Build
Hardware:	Unspecified
OS:	Unspecified
See Also:	https://bugs.webkit.org/show_bug.cgi?id=215410

Description Hector Lopez 2020-09-03 17:56:31 PDT

css2.1/t0905-c5525-fltwidth-00-c-g.html

Test is a constant failure according to history on iOS wk2. First occurrence of failure is at r(266509).

History:
https://results.webkit.org/?suite=layout-tests&test=css2.1%2Ft0905-c5525-fltwidth-00-c-g.html&platform=ios

Diff:
--- /Volumes/Data/slave/ios-simulator-13-release-tests-wk2/build/layout-test-results/css2.1/t0905-c5525-fltwidth-00-c-g-expected.txt
+++ /Volumes/Data/slave/ios-simulator-13-release-tests-wk2/build/layout-test-results/css2.1/t0905-c5525-fltwidth-00-c-g-actual.txt
@@ -46,7 +46,7 @@
           text run at (238,340) width 155: "ignore this float text"
           text run at (0,360) width 257: "ignore this float text ignore this float"
       RenderBlock {DIV} at (0,153) size 784x520 [color=#C0C0C0]
-        RenderText {#text} at (392,0) size 784x519
+        RenderText {#text} at (392,0) size 785x519
           text run at (392,0) width 392: "this is some dummy text this is some dummy text this is"
           text run at (392,20) width 99: "some dummy "
           text run at (490,20) width 294: "text this is some dummy text this is some"
@@ -79,7 +79,7 @@
           text run at (392,340) width 304: "dummy text this is some dummy text this is "
           text run at (695,340) width 89: "some dummy"
           text run at (392,360) width 354: "text this is some dummy text this is some dummy text "
-          text run at (745,360) width 39: "this is"
+          text run at (745,360) width 40: "this is"
           text run at (0,380) width 412: "some dummy text this is some dummy text this is some dummy "
           text run at (411,380) width 373: "text this is some dummy text this is some dummy text this"
           text run at (0,400) width 54: "is some "

1px off in both size and width. May just need re-baseline.

Comment 1 Radar WebKit Bug Importer 2020-09-03 17:56:51 PDT

<rdar://problem/68313002>

Comment 2 Hector Lopez 2020-09-03 18:03:00 PDT

Test expectation while investigated:

https://trac.webkit.org/changeset/266565/webkit

Comment 3 zalan 2020-09-04 12:11:43 PDT

This is a very unfortunate float arithmetic issue where the run's x position is now 0.000061px off -and the ceil() operation in "dump renderer as text" results in a different integral value ->
rect.x(745.766968) rect.width(38.233074) ceilf 785.000000
rect.x(745.766907) rect.width(38.233074) ceilf 784.000000