1112501 - ColumnSet, transforms, and fixed positions do not interact right

Status: RESOLVED FIXED

(Core :: Layout, defect)

Description

[David Anderson [:dvander] - inactive, e-mail if emergency]

Attachment: frame dump

Test case in URL, and frame dump attached. The <span> does not end up under the columnset, so it ends up with its reference frame being the viewport, whereas it should be the div since it has a transform.

Comment 1

[David Anderson [:dvander] - inactive, e-mail if emergency]

Attachment: bug1112501.patch

Matt Woodrow helped me debug this - what we concluded is this:
 1. ConstructBlock() is asked to construct a blockframe for a columnset.
 2. aPositionedFrameForAbsPosContainer == blockFrame
 3. We construct a new columnSetBlock, and steal the style from blockframe.
 4. blockframe's style gets reset.
 5. When we PushAbsoluteContainingBlock, we still think aPositionedFrame is the old blockFrame (now the parent frame), so it appears untransformed.

This patch fixes up aPositionedFrameForAbsPosContainer, but it wasn't clear whether it's ever *not* == blockFrame, and if so, what the correct behavior is.

Comment 2

[David Baron :dbaron: (⌚️UTC-4, no longer working on Mozilla)]

Comment on attachment 8537698 [details] [diff] [review]
bug1112501.patch

I guess this is ok, although I think this parameter could probably be simplified into either a boolean or (through a series of refactorings) into no parameter at all.

Please add a reftest that fails without the patch and passes with the patch.

r=dbaron with that

Comment 3

[David Anderson [:dvander] - inactive, e-mail if emergency]

remote:   https://hg.mozilla.org/integration/mozilla-inbound/rev/bce8b4207a45

Comment 4

[Carsten Book [:Tomcat]]

https://hg.mozilla.org/mozilla-central/rev/bce8b4207a45