24195 - Infinite reflow after adding content to scrollable frame

Status: VERIFIED FIXED

(Core :: Layout, defect, P3)

Description

[Robert Ginda]

The attached testcase causes an infinite reflow loop when a piece of content is
dynamically appended to a scrollable div.

scrollflow.xul defines an HTML:DIV, named 'scrolldiv', with an explicit width of
50px (any width seems to work) and a style of 'overflow: auto'.  Next to the div
is a box containing an HTML:INPUT control (this box is vertically aligned, h
alignment does not exibhit the failure.)  The onLoad handler inserts a
dynamically created HTML:SPAN tag into 'scrolldiv'.

The scrollflow.html file displays a button used to window.open the
scrollflow.xul chrome.  The failure does not appear to happen for non-chrome
urls.

Steps to reproduce:
1) save the first attachment as scrollflow.html to some directory
2) save the second attachment as scrollflow.xul in the same directory used in
step 1
3) click the 'click to open window' button.

Actual Results:
When the onLoad handler inserts the span, the window is reflowed forever,
causing Mozilla to freeze, and CPU usage to spike.  Each pass through the loop
in
http://lxr.mozilla.org/seamonkey/source/layout/html/base/src/nsPresShell.cpp:1902
adds two reflow commands to the mReflowCommands array.  The reflow commands are
inserted from the line
http://lxr.mozilla.org/seamonkey/source/layout/html/base/src/nsGfxScrollFrame.cpp:1474
.  This function appears to run twice during each reflow, oscillating between
two possible values for scrollAreaSize.height.

Expected Results:
A new window appears, with the text "dynamic span" on the left half, and a text
entry box on the right.


This bug is blocking chatzilla, although I've found that not specifying a width
for the scrolldiv is a temporary workaround.

This occurs on Linux and Windows, havn't tested on Mac.  The bustage is fairly
recent (I'd guess within a week or less.)

Comment 1

[Robert Ginda]

Attachment: scrollflow.html portion of testcase

Comment 2

[Robert Ginda]

Attachment: scrollflow.zul portion of testcase

Comment 3

[troy]

Scrolling problem so re-assigning to Eric

Comment 4

[Eric Vaughan]

targeting

Comment 5

[Peter Trudelle]

putting on beta1 radar

Comment 6

[Eric Vaughan]

The scrollflow.xul file is a LXR html file it is not a XUL file. Please supply 
another test case and reassign this back to me if it still happens.

Comment 7

[Robert Ginda]

No, its a text file.  Both attachments work for me here.
Did you right click on scrollflow.xul and do a "save as..."?

Comment 8

[Eric Vaughan]

targeting

Comment 9

[Eric Vaughan]

fixed

Comment 10

[Chris Petersen]

Fixed in the July 6th build.