Bug 15033 – REGRESSION (r25142, Tiger only): Vertical scroll bar not redrawn properly when going back in history

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

[David Kilzer (:ddkilzer)]

* SUMMARY
While navigating the webkit-unassigned mailing list (http://lists.macosforge.org/pipermail/webkit-unassigned/2007-August/date.html), there are times when I click on a message, then use Cmd-Left-Arrow to go back that the vertical scroll bar is not redrawn properly.

* STEPS TO REPRODUCE
1. Launch Safari/WebKit.
2. Go to URL:  http://lists.macosforge.org/pipermail/webkit-unassigned/2007-August/date.html
3. Scroll down the list to link http://lists.macosforge.org/pipermail/webkit-unassigned/2007-August/046941.html ([Webkit-unassigned] [Bug 15017] ASSERTION FAILED: size == 0 || size >= m_encodedSize in WebCore::CachedResource::setEncodedSize).
4. Click on it with the mouse.
5. Hit Cmd-Left-Arrow or browser back button to go back.

* EXPECTED RESULTS
Scroll bar should be redrawn for the longer results.

* ACTUAL RESULTS
Scroll bar is not redrawn, show a short and a long one (see screenshot to be attached).

* REGRESSION
This is a regression from shipping Safari 2.0.4 (419.3) with original WebKit on Mac OS X 10.4.10 (8R218).  Tested with a local debug build of WebKit r25168 with Safari 3 Public Beta v. 3.0.3 (522.12.1) on 10.4.10.

[David Kilzer (:ddkilzer)]

Created attachment 16047 [details]
Screenshot

[David Kilzer (:ddkilzer)]

The autospade script narrowed this down to:

Reproduced bug: r25145
Did NOT reproduce bug: r25140

Reviewing logs, r25142 looks suspicious:
http://trac.webkit.org/projects/webkit/changeset/25142

[David Kilzer (:ddkilzer)]

(In reply to comment #0)
> 3. Scroll down the list to link
> http://lists.macosforge.org/pipermail/webkit-unassigned/2007-August/046941.html
> ([Webkit-unassigned] [Bug 15017] ASSERTION FAILED: size == 0 || size >=
> m_encodedSize in WebCore::CachedResource::setEncodedSize).

The easiest way to find this is to search for "Bug 15013", and find the third occurrence on the page (which has the "Bug 15017" link just above it).

NOTE: If this bug is sensitive to scroll bar position, adding comments to webkit-unassigned make make the above link fail to reproduce the issue.  In that case, just start clicking on consecutive links, then hitting the back button (or Cmd-Left-Arrow) to find a reproducible case.

[David Kilzer (:ddkilzer)]

<rdar://problem/5424816>

[David Kilzer (:ddkilzer)]

(In reply to comment #3)
> (In reply to comment #0)
> > 3. Scroll down the list to link
> > http://lists.macosforge.org/pipermail/webkit-unassigned/2007-August/046941.html
> > ([Webkit-unassigned] [Bug 15017] ASSERTION FAILED: size == 0 || size >=
> > m_encodedSize in WebCore::CachedResource::setEncodedSize).

Just go to the bottom of the list, click on a link to a message, then click Back.  :)

[Adele Peterson]

dupe of <rdar://5441823>

Definitely caused by r25142.

[Richard Secor]

I cannot get this to happen in 5532.15 (Safari 3.0.4).
Tried exact directions given as-well-as randomly poking around and going back.

[David Kilzer (:ddkilzer)]

Yes, this was fixed by r26070.

http://trac.webkit.org/projects/webkit/changeset/26070

[David Kilzer (:ddkilzer)]

(In reply to comment #7)
> I cannot get this to happen in 5532.15 (Safari 3.0.4).
> Tried exact directions given as-well-as randomly poking around and going back.

Thanks for testing!