388254 - ###!!! ASSERTION: reflow state computed incorrect width: 'reflowState.ComputedWidth() == size.width - reflowState.mComputedBorderPadding.LeftRight()', mozilla/layout/base/nsPresShell.cpp:5978

Status: NEW

(Core :: Layout, defect)

Description

[Alex Vincent [:WeirdAl]]

Attachment: stack trace

Steps to reproduce:

(1) Build trunk XULRunner.
(2) Download http://downloads.mozdev.org/verbosio/snapshots/branch_20070713_tag_003.tar.gz
(3) tar -xzvf branch_20070713_tag_003.tar.gz
(4) ./xulrunner (path_to_verbosio_unzipped)/default/application.ini

Filed as UNCO because (a) Verbosio is not a mozilla.org product, (b) I am so far the only person working on Verbosio, and thus I haven't gotten independent confirmation.

Comment 1

[Alex Vincent [:WeirdAl]]

You should be able to reproduce this using the latest Verbosio snapshot, http://downloads.mozdev.org/verbosio/snapshots/branch_20070713_tag_006.tar.gz .  It probably hasn't hit the mirrors yet, though.

Comment 2

[Boris Zbarsky [:bzbarsky]]

Alex, thanks for helping debug this!

Looks like this is reflow of a collapsed scrollbar:

ScrollbarFrame(scrollbar)(-1)@0xb5d018b0 next=0xb5d02274 {6000,0,0,6000}
  [state=808c1001] [content=0x8d41278] [sc=0xb5d017f0]<

(gdb) p reflowState.ComputedWidth()
$3 = 0
(gdb) p size.width
$4 = 0
(gdb) p reflowState.mComputedBorderPadding.LeftRight()
$5 = 120

We probably shouldn't be reflowing this at all, if possible.  If we must, we'll have to change the assertion, since the rect is zero-width, and the computed width can't be negative.

The former would probably also fix bug 388255....

Not sure how to do that well, esp. if the scrollbar becomes uncollapsed sometime.

Comment 3

[Martin Mokrejs]

Attachment: full gdb stacktrace

I am getting something very similar during startup of seamonkey/browser with cuurent cvs HEAD build on i686 linux. Also see the 2 stacktraces (mis)attached by me to bug #369945.

Comment 4

[Boris Zbarsky [:bzbarsky]]

Please stop posting that on every bug with this assertion.  We know why this bug with scrollbars in particular is happening.  The question is how to fix it.

Comment 5

[Jesse Ruderman]

Bug 514784 has a testcase and might be the same as this bug.