Bug 213135

Summary: REGRESSION(r261985): Unable to respond to large comments on Bugzilla with always-on scrollbars
Product: WebKit Reporter: Chris Dumez <cdumez>
Component: ScrollingAssignee: Simon Fraser (smfr) <simon.fraser>
Status: RESOLVED FIXED    
Severity: Normal CC: ap, cmarcelo, ews-watchlist, fred.wang, ggaren, jamesr, koivisto, luiz, simon.fraser, thorton, tonikitoo, webkit-bug-importer
Priority: P2 Keywords: InRadar
Version: WebKit Nightly Build   
Hardware: Unspecified   
OS: Unspecified   
Bug Depends on:    
Bug Blocks: 212168    
Attachments:
Description Flags
Patch none

Description Chris Dumez 2020-06-12 10:01:53 PDT 
Unable to respond to large comments on Bugzilla:
1. Go to https://bugs.webkit.org/show_bug.cgi?id=212981
2. Click the "Reply" link next to comment #14
-> Notice that the page hangs
Comment 1 Chris Dumez 2020-06-12 10:02:40 PDT 
This is a recent regression, I am trying to bisect now.
Comment 2 Chris Dumez 2020-06-12 10:04:01 PDT 
Current regression range:
http://trac.webkit.org/log/trunk/?mode=follow_copy&rev=262244&stop_rev=261979
Comment 4 Radar WebKit Bug Importer 2020-06-12 10:18:55 PDT 
<rdar://problem/64302086>
Comment 5 Chris Dumez 2020-06-12 10:19:07 PDT 
Confirmed regression from Simon's http://trac.webkit.org/changeset/261985/webkit.
Comment 6 Simon Fraser (smfr) 2020-06-12 13:49:33 PDT 
We programmatically scroll on the main thread to reveal the text field, and then AsyncScrollingCoordinator::synchronizeStateFromScrollingTree() clobbers that scroll offset with the current state of the scrolling tree.
Comment 7 Simon Fraser (smfr) 2020-06-12 21:07:51 PDT 
Created attachment 401824 [details]
Patch
Comment 8 EWS 2020-06-12 23:13:17 PDT 
Committed r262996: <https://trac.webkit.org/changeset/262996>

All reviewed patches have been landed. Closing bug and clearing flags on attachment 401824 [details].